Java学习者

作者：微信小助手

<section style="width: 100%;margin-top: 10px;margin-right: auto;margin-left: auto;padding: 10px;display: flex;box-sizing: border-box;" data-width="100%"> <section style="width: 20px;border-top: 1px solid rgb(72, 83, 75);box-sizing: border-box;"> </section> <section style="width: 100%;border-top: 1px solid rgb(72, 83, 75);margin-left: 5px;box-sizing: border-box;" data-width="100%"></section> <section style="width: 40px;background: rgb(255, 255, 255) none repeat scroll 0% 0%;padding-right: 6px;padding-left: 6px;margin-top: -16px;box-sizing: border-box;"> <section style="width: 30px;"> <img class="" data-ratio="0.6551724137931034" src="/upload/edb1bb9a513def00fb8449722299462a.png" data-type="png" data-w="58" data-width="100%" style="width: 100% !important;height: auto !important;visibility: visible !important;" width="100%"> </section> </section> <section style="width: 100%;border-top: 1px solid rgb(72, 83, 75);margin-right: 5px;box-sizing: border-box;" data-width="100%"></section> <section style="width: 20px;border-top: 1px solid rgb(72, 83, 75);box-sizing: border-box;"> </section> </section> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;white-space: normal;background-color: rgb(255, 255, 255);">为什么需要 Stream  Stream 作为 Java 8 的一大亮点，它与 java.io 包里的 InputStream 和 OutputStream 是完全不同的概念。它也不同于 StAX 对 XML 解析的 Stream，也不是 Amazon Kinesis 对大数据实时处理的 Stream。Java 8 中的 Stream 是对集合（Collection）对象功能的增强，它专注于对集合对象进行各种非常便利、高效的聚合操作（aggregate operation），或者大批量数据操作 (bulk data operation)。Stream API 借助于同样新出现的 Lambda 表达式，极大的提高编程效率和程序可读性。同时它提供串行和并行两种模式进行汇聚操作，并发模式能够充分利用多核处理器的优势，使用 fork/join 并行方式来拆分任务和加速处理过程。通常编写并行代码很难而且容易出错, 但使用 Stream API 无需编写一行多线程的代码，就可以很方便地写出高性能的并发程序。所以说，Java 8 中首次出现的 java.util.stream 是一个函数式语言+多核时代综合影响的产物。 <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;white-space: normal;background-color: rgb(255, 255, 255);"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;font-size: 16px;text-align: justify;background-color: rgb(255, 255, 255);">1. Java 7 的排序、取值实现 <img class="" data-backh="330" data-backw="558" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3Sia4bM2DCKCia1W5GYW39PvRDAoAKZGHo3JcIib63o3VOVr7JWcB0l9P9A/0?wx_fmt=png" data-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_jpg/48MFTQpxichntAkr4Wmc26VYKChciaEF3Szap4FamSwsVcwIdrM3S1tAbFc4N1SvPtTGKqricicbPcCzrHwet0Mg8g/0?wx_fmt=jpeg" data-ratio="0.5925925925925926" data-s="300,640" src="/upload/317a0803e1cb0df22bbe80846a14eaba.jpg" data-type="jpeg" data-w="567" style="width: 100%;height: auto;"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;font-size: 16px;text-align: justify;background-color: rgb(255, 255, 255);"> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;white-space: normal;background-color: rgb(255, 255, 255);">而在 Java 8 使用 Stream，代码更加简洁易读；而且使用并发模式，程序执行速度更快。 <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;white-space: normal;background-color: rgb(255, 255, 255);">2. Java 8 的排序、取值实现 <img class="" data-backh="123" data-backw="500" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3Sjw6PJNPrVy62RS9RxjKkvNEFxZjv5Ld8IVhvNKElRRgYm6krnObmicA/0?wx_fmt=png" data-ratio="0.24649298597194388" data-s="300,640" src="/upload/1c57dc9c8419b24a3167a94e778ccaf3.png" data-type="png" data-w="499" style="width: 100%;height: auto;"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;font-size: 16px;text-align: justify;background-color: rgb(255, 255, 255);"> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;white-space: normal;background-color: rgb(255, 255, 255);"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;font-size: 16px;text-align: justify;background-color: rgb(255, 255, 255);"><span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif, SimHei, SimSun;font-size: 16px;text-align: justify;background-color: rgb(255, 255, 255);">3. 一个流操作的示例 <img class="" data-backh="106" data-backw="478" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3Se4TTnd0bSct7LU8PydCvhEVRf4WDMVGGCspvrYWibZhwCEoGsk9nFicA/0?wx_fmt=png" data-ratio="0.22012578616352202" data-s="300,640" src="/upload/7ea8d6dc4c6d425af32fd3ae791a48d2.png" data-type="png" data-w="477" style="width: 100%;height: auto;"> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">stream() 获取当前小物件的 source，filter 和 mapToInt 为 intermediate 操作，进行数据筛选和转换，最后一个 sum() 为 terminal 操作，对符合条件的全部小物件作重量求和。 <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);"> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">下面提供最常见的几种构造 Stream 的样例。 <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">4. 构造流的几种常见方法 <img class="" data-backh="214" data-backw="507" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3ShoKmiaq2UoH3ibBZmxbuQ4nIPfib4Fhxp35pqRbAxtbB8yz66DG0jia3Bw/0?wx_fmt=png" data-ratio="0.42292490118577075" data-s="300,640" src="/upload/9414c7c7e487de9455919a8a2aebf1da.png" data-type="png" data-w="506" style="width: 100%;height: auto;"> <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">需要注意的是，对于基本数值型，目前有三种对应的包装类型 Stream： <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">IntStream、LongStream、DoubleStream。当然我们也可以用 Stream、Stream >、Stream，但是 boxing 和 unboxing 会很耗时，所以特别为这三种基本数值型提供了对应的 Stream。 <p style="box-sizing: border-box;outline: 0px;margin-bottom: 16px;font-size: 16px;color: rgb(79, 79, 79);line-height: 26px;text-align: justify;word-break: break-all;font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-variant-ligatures: common-ligatures;white-space: normal;background-color: rgb(255, 255, 255);">Java 8 中还没有提供其它数值型 Stream，因为这将导致扩增的内容较多。而常规的数值型聚合运算可以通过上面三种 Stream 进行。 <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">5. 数值流的构造 <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <img class="" data-backh="76" data-backw="556" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SQ4knWj21ibzSYvr0uadUZ8s0ibYKxojCADXLC1ic37jOXs8RFEBGsxBZA/0?wx_fmt=png" data-ratio="0.13513513513513514" data-s="300,640" src="/upload/57be3214e02c450e925e93ff13f2c5cc.png" data-type="png" data-w="555" style="width: 100%;height: auto;"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">6. 转换大写<span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <span class="hljs-built_in" style="box-sizing: border-box;outline: 0px;color: rgb(79, 79, 79);font-size: 14px;word-break: break-all;font-family: Consolas, Inconsolata, Courier, monospace;font-variant-ligatures: common-ligatures;white-space: pre;"> <img class="" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SkiaHwwfEgw8SdYHW37vX5o2gxnRW9qBDXUQAYRdC7XAmIkUic9L1Teeg/0?wx_fmt=png" data-ratio="0.21508379888268156" data-s="300,640" src="/upload/13572e901e47985d59040b82fc61ff13.png" data-type="png" data-w="358" style="width: 358px;height: auto;"> <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">这段代码能把所有的单词转换为大写。 <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">8. 平方数 <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span class="hljs-built_in" style="box-sizing: border-box;outline: 0px;color: rgb(79, 79, 79);font-size: 14px;word-break: break-all;font-family: Consolas, Inconsolata, Courier, monospace;font-variant-ligatures: common-ligatures;white-space: pre;"> <img class="" data-ratio="0.19769673704414586" data-s="300,640" src="/upload/1ff11dce2d8ad495e2cf4aaaae343164.png" data-type="png" data-w="521" style=""> <span style="color: rgb(79, 79, 79);font-variant-ligatures: common-ligatures;font-weight: 700;text-align: justify;font-family: Consolas, Inconsolata, Courier, monospace;font-size: 14px;white-space: pre;background-color: rgb(246, 248, 250);"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">9 一对多 <img class="" data-ratio="0.2526997840172786" data-s="300,640" src="/upload/f85e13d8ba5c4e64747a3cafa4235cdb.png" data-type="png" data-w="463" style=""> Stream流里面还可以将多个集合转换至一个stream流中 <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;font-weight: 700;text-align: justify;white-space: pre;background-color: rgb(255, 255, 255);">10 使用foreach打印 <img class="" data-backh="231" data-backw="452" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3Sw52pvQMFdCWwCsDa30BGzPRBwPFCUCWX5mbmPBK7iaL6oiaNiajKaEWDQ/0?wx_fmt=png" data-ratio="0.5110619469026548" data-s="300,640" src="/upload/2019a22922c1bc4f98c4f2231731a165.png" data-type="png" data-w="452" style="width: 100%;height: auto;"> <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">对一个人员集合遍历，找出男性并打印姓名。可以看出来，forEach 是为 Lambda 而设计的，保持了最紧凑的风格。而且 Lambda 表达式本身是可以重用的，非常方便。当需要为多核系统优化时，可以 parallelStream().forEach()，只是此时原有元素的次序没法保证，并行的情况下将改变串行时操作的行为，此时 forEach 本身的实现不需要调整，而 Java8 以前的 for 循环 code 可能需要加入额外的多线程逻辑。 <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;font-weight: 700;text-align: justify;white-space: pre;background-color: rgb(255, 255, 255);">11 reduce 的使用用例 <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"> <img class="" data-ratio="0.4161616161616162" data-s="300,640" src="/upload/486e8a190d423561c1ce2a9994f36fbd.png" data-type="png" data-w="495" style=""> <span style="color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);"><span style="box-sizing: border-box;outline: 0px;font-weight: 700;word-break: break-all;color: rgb(79, 79, 79);font-family: -apple-system, "SF UI Text", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;font-size: 16px;font-variant-ligatures: common-ligatures;text-align: justify;background-color: rgb(255, 255, 255);">jdk8里面的reduce提供了相应的求和函数和最大值，最小值功能。 利用reduce和map的搭配，我们可以做一些数值流的转换功能，例如说： <img class="" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SYyTLKibtZPOFDdEFraMd36qnibnBtZQFeAygSYAL4zHricetKnHRunE8A/0?wx_fmt=png" data-ratio="0.4567307692307692" data-s="300,640" src="/upload/50110c27d1c93bf699eff860340d6442.png" data-type="png" data-w="416" style="width: 416px;height: auto;"> 12 filter去重筛选 java8里面的filter是最常用来去重的操作了，下面这个案例主要是演示如何使用filter来筛选数字。 <img class="" data-backh="246" data-backw="558" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SiaLcLCpicVzvxsLYQSIjYiaibGIOawL4CWH7FaWJ2TjVTzFV50RYicoAWkA/0?wx_fmt=png" data-ratio="0.43963254593175854" data-s="300,640" src="/upload/52868dca939937724a8a0b8abedf031b.png" data-type="png" data-w="762" style="width: 100%;height: auto;"> 13.Map和flatMap映射 <img class="" data-backh="337" data-backw="558" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SgqXoyKjr4y8icnhFF3kAxKmyOLfkmVgGIf70KZB5GStHOYcO8rjeJLw/0?wx_fmt=png" data-ratio="0.6042003231017771" data-s="300,640" src="/upload/160812bddeaf534a3757090c6a4bf356.png" data-type="png" data-w="619" style="width: 100%;height: auto;"> 使用map和flatmap的映射可以减少冗余代码的产生，更加地使得我们的代码精简化。 同时map也可以对于数组类型进行映射： <img class="" data-backh="321" data-backw="471" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3ScDrK3lCkf3aVlS7EcDUiabMhB4oRa8tz0E44ibeWdfIWAFMe7l3fkMIw/0?wx_fmt=png" data-ratio="0.6800847457627118" data-s="300,640" src="/upload/50ff56a1180f643a770b778f4b80f865.png" data-type="png" data-w="472" style="width: 100%;height: auto;"> 14.查找和匹配 jdk8里面提供了多种stream的函数，例如anyMatch，allMatch，noneMatch等 <img class="" data-backh="479" data-backw="558" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SWnAwwaCMyibMUaSWdIx2miat0LPwbefO9ic6oLMgjvHKDA3y4fQicfuBGA/0?wx_fmt=png" data-ratio="0.8586206896551725" data-s="300,640" src="/upload/c914e38c9931ea518794b2b7c0ceed96.png" data-type="png" data-w="580" style="width: 100%;height: auto;"> 15.skip操作 <img class="" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/48MFTQpxichntAkr4Wmc26VYKChciaEF3SFkswpZNRODicE67qY8Z9pxeqj89ib9416mBmmRx5YZUHbicRMqM0R4EFg/0?wx_fmt=png" data-ratio="0.4147982062780269" data-s="300,640" src="/upload/30f1114001f602f452e84e6afbc981e1.png" data-type="png" data-w="446" style="width: 447px;height: auto;"> jdk8里面的skip操作可以直接跳过相应的元素，它的作用正好和limit功能互补。 16.分组操作 之前在公司的项目里面就有用到过分组操作，这种操作主要可以用于优化类似于Map<String,List<Object>>的数据结构，案例如下： <img class="" data-ratio="0.25375170532060026" data-s="300,640" src="/upload/ea1e528b3f63acf1b4d63e9fd9b52827.png" data-type="png" data-w="733" style=""> 使用groupby操作，直接可以将list中的每个元素，按照一定的规则来进行分类，这是一种特别高效率的手段 <section style="margin: 30px auto;max-width: 100%;text-align: center;box-sizing: border-box !important;word-wrap: break-word !important;"> <section style="margin-right: auto;margin-left: auto;max-width: 100%;box-sizing: border-box;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 120px;height: 120px;transform: rotate(30deg);word-wrap: break-word !important;"> <section class="" style="max-width: 100%;box-sizing: border-box;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 120px;height: 120px;transform: rotate(-15deg);word-wrap: break-word !important;"> <img class="KolImg" data-backh="109.02272" data-backw="109.02272" data-ratio="1" src="/upload/6dc5b486d325bd279b6bf85ff89fd231.jpg" data-type="jpeg" data-w="258" style="box-sizing: border-box;height: auto;z-index: -1;cursor: pointer;width: 100%;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);float: left;transform: rotate(-15deg);word-wrap: break-word !important;"> </section> </section> </section> <section style="max-width: 100%;box-sizing: border-box !important;word-wrap: break-word !important;"> 长按二维码 就可以关注我们啦~ </section>

25个常用的Linux iptables规则

作者：微信小助手

<section class="xmteditor" style="display:none;" data-tools="新媒体管家" data-label="powered by xmt.cn"></section> <section class="xmteditor" style="display:none;" data-tools="新媒体管家" data-label="powered by xmt.cn"></section> <section class="xmteditor" style="display:none;" data-tools="新媒体管家" data-label="powered by xmt.cn"></section> <img class="" data-copyright="0" data-ratio="0.4166666666666667" src="/upload/f6a61a047bb8f91d1d106b25e45f1c24.gif" data-type="gif" data-w="600" style="color: rgb(51, 51, 51);font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif;font-size: 17px;letter-spacing: 1px;text-align: justify;white-space: normal;border-radius: 4px;box-shadow: none;"> <section class="" data-tools="135编辑器" data-id="91525"> <section style="margin: 8px;padding: 10px;max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;line-height: 25.6px;border-radius: 10px;height: auto;box-shadow: rgb(221, 221, 221) 2px 2px 8px;display: -webkit-flex;"> <section style="max-width: 100%;flex: 0 0 2cm;height: 78px;width: 75px;box-sizing: border-box !important;word-wrap: break-word !important;"> <a href="https://mp.weixin.qq.com/s?__biz=MzU2MzcxNzgwMg==&mid=2247483650&idx=3&sn=7d8d32410010e2f58a8b0e9b15fa23ec&scene=21#wechat_redirect" target="_blank" data-linktype="1"><img class="" data-copyright="0" data-cropselx1="0" data-cropselx2="76" data-cropsely1="0" data-cropsely2="74" data-ratio="1" src="/upload/c978be494b76a0bf054d19dfd16ca72d.jpg" data-type="jpeg" data-w="456" style="letter-spacing: 0.544px;text-align: justify;color: rgb(62, 62, 62);border-radius: 37px;width: 76px;height: 76px;margin: 0px;box-sizing: border-box !important;word-wrap: break-word !important;visibility: visible !important;box-shadow: rgb(170, 170, 170) 0px 0px 14px 0px;"></a> </section> <section style="padding-right: 10px;padding-left: 10px;max-width: 100%;box-sizing: border-box;flex: 1 1 auto;height: 55px;word-wrap: break-word !important;"> <section style="max-width: 100%;line-height: 35px;white-space: nowrap;box-sizing: border-box !important;word-wrap: break-word !important;"> <a href="https://mp.weixin.qq.com/s?__biz=MzU2MzcxNzgwMg==&mid=2247483650&idx=3&sn=7d8d32410010e2f58a8b0e9b15fa23ec&scene=21#wechat_redirect" target="_blank" data-linktype="2">Linux编程</a> </section> <section style="max-width: 100%;font-size: 13px;line-height: 20px;color: rgb(127, 127, 127);box-sizing: border-box !important;word-wrap: break-word !important;"> <a href="https://mp.weixin.qq.com/s?__biz=MzU2MzcxNzgwMg==&mid=2247483650&idx=3&sn=7d8d32410010e2f58a8b0e9b15fa23ec&scene=21#wechat_redirect" target="_blank" data-linktype="2">点击右侧关注，免费入门到精通！</a> </section> </section> <section style="max-width: 100%;flex: 0 0 1.5cm;font-size: 15px;color: rgb(86, 187, 55);letter-spacing: 0px;text-align: center;line-height: 6;box-sizing: border-box !important;word-wrap: break-word !important;"> <section style="margin-top: 25px;max-width: 100px;vertical-align: middle;overflow: hidden;box-sizing: border-box !important;word-wrap: break-word !important;"> <section style="max-width: 100%;width: 55px;height: 30px;box-sizing: border-box !important;word-wrap: break-word !important;background-image: url(https://mmbiz.qpic.cn/mmbiz_gif/S7SAuLQzeTVj0YaoibbZqxicYkQrLnR3WtTQlHpHouqUmibjUCY9F5wpG0DmyMetZy9pjDdiabWo4XXdtCib3VcnI7w/640?wx_fmt=gif);background-size: 100% 100%;background-repeat: no-repeat;"> <section style="max-width: 100%;opacity: 0;box-sizing: border-box !important;word-wrap: break-word !important;"> <a href="https://mp.weixin.qq.com/s?__biz=MzU2MzcxNzgwMg==&mid=2247483650&idx=3&sn=7d8d32410010e2f58a8b0e9b15fa23ec&scene=21#wechat_redirect" target="_blank" data-linktype="1"><img class="" data-copyright="0" data-cropselx1="0" data-cropselx2="56" data-cropsely1="0" data-cropsely2="56" data-ratio="1" src="/upload/f92c6b5f891800a8e8a41e6dad1950e4.jpg" data-type="jpeg" data-w="258" style="margin: 0px;top: auto;left: auto;right: auto;bottom: auto;width: 56px;height: 56px;box-sizing: border-box !important;word-wrap: break-word !important;visibility: visible !important;" title="1081255447.jpg"></a> </section> </section> </section> </section> </section> </section> 作者丨数据库开发 http://os.51cto.com/art/201709/551245.htm 一些常用的 Linux iptables 规则，请根据自己的具体需要再修改。 <img border="0" class="" data-ratio="0.5867895545314901" src="/upload/e8d9527389bc666377fc64daf980c19b.jpg" data-type="jpeg" data-w="651" style="border: none;box-shadow: none;border-radius: 24px;box-sizing: border-box !important;word-wrap: break-word !important;width: 651px !important;visibility: visible !important;" title=""> # 1. 删除所有现有规则 <img class="" data-ratio="0.10434782608695652" data-s="300,640" src="/upload/655bc7a9d5987e7177dcabd3cc15e786.png" data-type="png" data-w="345" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 345px !important;visibility: visible !important;"> # 2. 设置默认的 chain 策略 <img class="" data-ratio="0.3353846153846154" data-s="300,640" src="/upload/7ac76b88430ae7e0819a205618b32b33.png" data-type="png" data-w="325" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 325px !important;visibility: visible !important;">  # 3. 阻止某个特定的 IP 地址 <img class="" data-ratio="0.1745635910224439" data-s="300,640" src="/upload/e02e9019ab5115479d18e03455ae30e4.png" data-type="png" data-w="401" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 401px !important;visibility: visible !important;"> # 4. 允许全部进来的(incoming)SSH <img class="" data-ratio="0.10792580101180438" data-s="300,640" src="/upload/7f9b1763ea5babdec3b798f5193b951b.png" data-type="png" data-w="593" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 593px !important;visibility: visible !important;"> # 5. 只允许某个特定网络进来的 SSH <img class="" data-ratio="0.09396914446002805" data-s="300,640" src="/upload/cd018dd3cfd9e933bf9001536fd42a32.png" data-type="png" data-w="713" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 6. 允许进来的(incoming)HTTP <img class="" data-ratio="0.11513157894736842" data-s="300,640" src="/upload/3ab054042dd2a8a3ca999f249530f7dc.png" data-type="png" data-w="608" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 608px !important;visibility: visible !important;"> # 7. 多端口(允许进来的 SSH、HTTP 和 HTTPS) <img class="" data-ratio="0.09537166900420757" data-s="300,640" src="/upload/1b82d26e1e44211015a368ffd9c4f6bf.png" data-type="png" data-w="713" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 8. 允许出去的(outgoing)SSH <img class="" data-ratio="0.11093247588424437" data-s="300,640" src="/upload/b632eda6b39dc7f08cfc1b4879f4286b.png" data-type="png" data-w="622" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 622px !important;visibility: visible !important;"> # 9. 允许外出的(outgoing)SSH，但仅访问某个特定的网络 <img class="" data-ratio="0.09192200557103064" data-s="300,640" src="/upload/17502dcd364ff1b29bb32e80874f58d3.png" data-type="png" data-w="718" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 10. 允许外出的(outgoing) HTTPS <img class="" data-ratio="0.11594202898550725" data-s="300,640" src="/upload/363ba4fd1e131d484316cc8b052a3022.png" data-type="png" data-w="621" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 621px !important;visibility: visible !important;"> # 11. 对进来的 HTTPS 流量做负载均衡 <img class="" data-ratio="0.24489795918367346" data-s="300,640" src="/upload/9526a5cf37c2ac104190e4d328bb8f68.png" data-type="png" data-w="686" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 12. 从内部向外部 Ping <img class="" data-ratio="0.1183206106870229" data-s="300,640" src="/upload/6b53927ded838d32456885cdf911964b.png" data-type="png" data-w="524" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 524px !important;visibility: visible !important;"> # 13. 从外部向内部 Ping <img class="" data-ratio="0.13821138211382114" data-s="300,640" src="/upload/854e8a74fc11346b16ad0f506c91195a.png" data-type="png" data-w="492" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 492px !important;visibility: visible !important;"> # 14. 允许环回(loopback)访问 <img class="" data-ratio="0.2098360655737705" data-s="300,640" src="/upload/b4d98e61d24ccc996d1578d1bac5c734.png" data-type="png" data-w="305" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 305px !important;visibility: visible !important;"> # 15. 允许 packets 从内网访问外网 <img class="" data-ratio="0.22453222453222454" data-s="300,640" src="/upload/41423f62a46942d1e67c8f17e8fa7e24.png" data-type="png" data-w="481" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 481px !important;visibility: visible !important;"> # 16. 允许外出的 DNS <img class="" data-ratio="0.15536105032822758" data-s="300,640" src="/upload/81c3eab103b5d8dc7a5c062d8b62b284.png" data-type="png" data-w="457" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 457px !important;visibility: visible !important;"> # 17. 允许 NIS 连接 <img class="" data-ratio="0.5261044176706827" data-s="300,640" src="/upload/ead293126cdd9954d8ad9eb936511009.png" data-type="png" data-w="498" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 498px !important;visibility: visible !important;"> # 18. 允许某个特定网络 rsync 进入本机 <img class="" data-ratio="0.1348973607038123" data-s="300,640" src="/upload/af758a64591f77eb9cb95524cc44de2d.png" data-type="png" data-w="682" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 19. 仅允许来自某个特定网络的 MySQL 的链接 <img class="" data-ratio="0.11884057971014493" data-s="300,640" src="/upload/de06b9f389f30b5587cb6b2035b1d695.png" data-type="png" data-w="690" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> # 20. 允许 Sendmail 或 Postfix <img class="" data-ratio="0.11410459587955626" data-s="300,640" src="/upload/b80d427cab3c3bcaa6a9df6920908f9b.png" data-type="png" data-w="631" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 631px !important;visibility: visible !important;"> # 21. 允许 IMAP 和 IMAPS <img class="" data-ratio="0.25283630470016205" data-s="300,640" src="/upload/301f1358d7122342964e77f46813ff61.png" data-type="png" data-w="617" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 617px !important;visibility: visible !important;"> # 22. 允许 POP3 和 POP3S <img class="" data-ratio="0.23410852713178296" data-s="300,640" src="/upload/bf8fe5505f592e47274a0fc35f149702.png" data-type="png" data-w="645" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 645px !important;visibility: visible !important;"> # 23. 防止 DoS 攻击 <img class="" data-ratio="0.0589171974522293" data-s="300,640" src="/upload/9809409e22220d65af0e0d04f869cb3f.png" data-type="png" data-w="628" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 628px !important;visibility: visible !important;"> # 24. 设置 422 端口转发到 22 端口 <img class="" data-ratio="0.1746987951807229" data-s="300,640" src="/upload/694803eff9261cc1b6b47b4a1dbd34da.png" data-type="png" data-w="664" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 664px !important;visibility: visible !important;"> # 25. 为丢弃的包做日志(Log) <img class="" data-ratio="0.21813031161473087" data-s="300,640" src="/upload/2c719df80a6ec1d07562e68b8e699418.png" data-type="png" data-w="706" style="box-shadow: none;box-sizing: border-box !important;word-wrap: break-word !important;width: 677px !important;visibility: visible !important;"> <section class="xmteditor" style="display:none;" data-tools="新媒体管家" data-label="powered by xmt.cn"></section> <section class="xmteditor" style="display:none;" data-tools="新媒体管家" data-label="powered by xmt.cn"></section>  推荐↓↓↓  <section style="box-sizing: border-box;"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin: 80px 0% 10px;text-align: center;box-sizing: border-box;"> <section style="display: inline-block;vertical-align: top;width: 100%;padding-right: 10px;padding-bottom: 10px;padding-left: 10px;border-radius: 12px;border-width: 0px;border-style: none;border-color: rgb(62, 62, 62);box-sizing: border-box;background-color: rgba(205, 234, 242, 0.96);"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: -70px;margin-right: 0%;margin-left: 0%;box-sizing: border-box;"> <section style="max-width: 100%;vertical-align: middle;display: inline-block;width: 60%;border-width: 5px;border-style: solid;border-color: rgba(100, 217, 251, 0.96);border-radius: 0px;box-sizing: border-box;"> <img class="" data-copyright="0" data-cropselx1="0" data-cropselx2="313" data-cropsely1="0" data-cropsely2="313" data-ratio="1" src="/upload/a04f15a62950ae7679e06356298b7b41.png" data-type="png" data-w="258" style="vertical-align: middle;width: 313px;box-sizing: border-box;height: 313px;"> </section> </section> </section> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="box-sizing: border-box;"> <section style="display: inline-block;vertical-align: top;width: 16%;box-sizing: border-box;"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: 10px;margin-right: 0%;margin-left: 0%;font-size: 10px;box-sizing: border-box;"> <section style="padding: 4px;display: inline-block;border-radius: 100%;box-sizing: border-box;background-color: rgba(0, 0, 0, 0);"> <section style="border-radius: 100%;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 2em;height: 2em;font-size: 13px;line-height: 1.8em;box-sizing: border-box;"> 长 </section> </section> </section> </section> </section> <section style="display: inline-block;vertical-align: top;width: 16%;box-sizing: border-box;"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: 10px;margin-right: 0%;margin-left: 0%;font-size: 10px;box-sizing: border-box;"> <section style="padding: 4px;display: inline-block;border-radius: 100%;box-sizing: border-box;background-color: rgba(0, 0, 0, 0);"> <section style="border-radius: 100%;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 2em;height: 2em;font-size: 13px;line-height: 1.8em;box-sizing: border-box;"> 按 </section> </section> </section> </section> </section> <section style="display: inline-block;vertical-align: top;width: 16%;box-sizing: border-box;"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: 10px;margin-right: 0%;margin-left: 0%;font-size: 10px;box-sizing: border-box;"> <section style="padding: 4px;display: inline-block;border-radius: 100%;box-sizing: border-box;background-color: rgba(0, 0, 0, 0);"> <section style="border-radius: 100%;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 2em;height: 2em;font-size: 13px;line-height: 1.8em;box-sizing: border-box;"> 关 </section> </section> </section> </section> </section> <section style="display: inline-block;vertical-align: top;width: 16%;box-sizing: border-box;"> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: 10px;margin-right: 0%;margin-left: 0%;font-size: 10px;box-sizing: border-box;"> <section style="padding: 4px;display: inline-block;border-radius: 100%;box-sizing: border-box;background-color: rgba(0, 0, 0, 0);"> <section style="border-radius: 100%;border-width: 2px;border-style: solid;border-color: rgb(0, 0, 0);width: 2em;height: 2em;font-size: 13px;line-height: 1.8em;box-sizing: border-box;"> 注 </section> </section> </section> </section> </section> </section> </section> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin-top: 10px;margin-right: 0%;margin-left: 0%;box-sizing: border-box;"> <section style="font-size: 14px;color: rgb(68, 68, 68);padding-right: 15px;padding-left: 15px;box-sizing: border-box;"> 👉【<a href="https://mp.weixin.qq.com/s?__biz=MzUzMDc0NzU4Nw==&mid=2247483768&idx=1&sn=4ef4f1510616baa395c507e32bb439d7&scene=21#wechat_redirect" target="_blank" style="text-decoration: underline;color: rgb(255, 79, 121);font-size: 17px;" data-linktype="2">16个技术公众号</a>】都在这里！ </section> </section> </section> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="margin: 8px 0% 15px;box-sizing: border-box;"> <section style="height: 1px;box-sizing: border-box;background-color: rgb(0, 0, 0);"></section> </section> </section> <section class="V5" style="box-sizing: border-box;" powered-by="xiumi.us"> <section style="box-sizing: border-box;"> <section style="text-align: left;box-sizing: border-box;"> 涵盖：程序员大咖、源码共读、程序员共读、数据结构与算法、黑客技术和网络安全、大数据科技、编程前端、Java、Python、Web编程开发、Android、iOS开发、Linux、数据库研发、幽默程序员等。 </section> </section> </section> </section> </section> </section> </section> <section data-role="outer" label="Powered by 135editor.com" style="max-width: 100%;font-size: 16px;font-family: 微软雅黑;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" data-tools="135编辑器" data-id="94250" style="max-width: 100%;box-sizing: border-box;border-width: 0px;border-style: none;border-color: initial;word-wrap: break-word !important;"> <section class="" data-tools="135编辑器" data-id="91842" style="max-width: 100%;box-sizing: border-box;border-width: 0px;border-style: none;border-color: initial;word-wrap: break-word !important;"> <section style="max-width: 100%;text-align: right;width: auto;box-sizing: border-box !important;word-wrap: break-word !important;"> <section style="max-width: 100%;display: inline-block;clear: both;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" data-brushtype="text" style="padding: 18px 15px 20px 10px;max-width: 100%;box-sizing: border-box;color: rgb(86, 146, 214);background-image: url("https://mmbiz.qpic.cn/mmbiz_png/ol72Wnba7fLkfGhCjKwHfZOmHMkVTIomF2Oicxr71sYib6EI8Hyhwtntt683HCer9AfzlYzWQ12A8LiaTuUutwvtg/640?wx_fmt=png");background-repeat: no-repeat;text-align: center;background-size: 100% 100%;letter-spacing: 1.5px;word-wrap: break-word !important;"> <section style="max-width: 100%;display: flex;justify-content: center;align-items: center;box-sizing: border-box !important;word-wrap: break-word !important;"> <section style="margin-left: 2px;max-width: 100%;width: 20px;box-sizing: border-box !important;word-wrap: break-word !important;"> <img class="" data-ratio="0.8936170212765957" src="/upload/737696b8734b6f688ae95660c4411917.png" data-type="png" data-w="47" style="margin-bottom: -6px;box-sizing: border-box !important;word-wrap: break-word !important;width: 20px !important;visibility: visible !important;"> </section> <section class="" data-brushtype="text" style="max-width: 100%;font-size: 14px;color: rgb(51, 51, 51);box-sizing: border-box !important;word-wrap: break-word !important;"> 万水千山总是情，点个 “ 好看” 行不行 </section> </section> </section> </section> </section> </section> </section> </section>

【分布式事务】基于RocketMQ搭建生产级消息集群？

作者：微信小助手

<img class="" data-backh="293" data-backw="556" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_jpg/l89kosVutonDlJQHqx8ib2qgeicbx1Nwq3nR3YibRia1eLYibfYoIY5uJqDHUSKHSL7XSW2gPLZQ8lpme9TI8aExFtQ/0?wx_fmt=jpeg" data-croporisrc="/upload/5915af3c8f57b51acd908e1658cf3a4c.jpg" data-cropx1="0" data-cropx2="1080" data-cropy1="0" data-cropy2="569.1366906474819" data-ratio="0.5268518518518519" data-s="300,640" src="https://mmbiz.qpic.cn/mmbiz_jpg/l89kosVutonDlJQHqx8ib2qgeicbx1Nwq3nR3YibRia1eLYibfYoIY5uJqDHUSKHSL7XSW2gPLZQ8lpme9TI8aExFtQ/640?wx_fmt=jpeg" data-type="jpeg" data-w="1080" style="width: 100%;height: auto;"> 导读 目前很多互联网公司的系统都在朝着微服务化、分布式化系统的方向在演进，这带来了很多好处，也带来了一些棘手的问题，其中最棘手的莫过于数据一致性问题了。早期我们的软件功能都在一个进程中，数据的一致性可以通过数据库本地事务来加以控制。而在分布式架构下，原本比较完整的本地功能可能被拆分成了多个独立的服务进程。与之前相比，同样一笔业务订单此时可能会经历很多服务模块的处理，调用链路会变得很长，例如某电商平台，一笔购物订单可能会经过：商品中心、订单、支付、物流等多个服务的调用，而这可能还只是比较粗粒度的划分，某些比较大型的服务，如支付系统，可能本身又会按照分布式的架构拆分成多个微服务，所以整个业务的调用链路会变得更加冗长。 而这不可避免的就会产生数据不一致的问题，为了实现业务上的最终一致性，功能比较独立的系统，如订单系统与支付系统就会通过额外的业务逻辑设计来确保彼此之间的最终一致性，如订单系统会通过订单的支付状态来保持与支付系统的数据一致，而支付系统则会提供支付状态查询接口，或者实现最大可能的主动回调功能，来确保二者数据状态的最终一致。此外可能还会通过日终的订单对账来发现不一致的数据，并进行数据校正。 但是这些都只是业务逻辑上的手段，对于某些内部服务之间的调用，如果可以通过分布式事务解决方案来加以保证的话，其实是可以大大减少一些不必要的复杂业务逻辑的。实际上，目前市面上能够提供分布式事务解决方案、又比较成熟的开源技术框架比较少，而RocketMQ在4.3.0之后的版本提供了事务消息的功能，因为RocketMQ本身拥有比较多的生产实践的关系，所以这一功能备受关注，作者所在的公司也有一些实践。 以此为契机，为了给大家关于分布式事务一个比较清晰的认识，这里我打算以RocketMQ的事务消息功能为示例，来相对全面的总结下分布式事务的内容。本篇文章的主要内容，是先介绍如何搭建一套生产级的RocketMQ消息集群，以此准备下试验环境。在下一篇《【分布式事务】基于RocketMQ的分布式事务实现》会整体介绍下分布式事务的概念和原理，并做一些代码级的试验。 什么是RocketMQ RocketMQ是阿里开源的并贡献给Apache基金会的一款分布式消息平台，它具有低延迟、高性能和可靠性、万亿级容量和灵活的可伸缩性的特点，单机也可以支持亿级的消息堆积能力、单机写入TPS单实例约7万条/秒，单机部署3个Broker，可以跑到最高12万条/秒。 基于以上强大的性能，以及阿里的技术影响力，RocketMQ目前在国内互联网公司中被使用得比较广泛。那么，我们先大概来了解一下RocketMQ的整体结构吧！ 整个RocketMQ消息系统主要由如下4个部分组成： 从中间件服务角度来看整个RocketMQ消息系统（服务端）主要分为：NameSrv和Broker两个部分。 NameSrv：在RocketMQ分布式消息系统中，NameSrv主要提供两个功能： <section class="" style="max-width: 100%;font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif;text-align: justify;white-space: normal;background-color: rgb(255, 255, 255);font-size: 16px;letter-spacing: 0px;color: rgb(62, 62, 62);line-height: 1.6;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <blockquote style="max-width: 100%;color: rgb(51, 51, 51);font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif;font-size: 17px;letter-spacing: 0.544px;text-align: justify;white-space: normal;box-sizing: border-box !important;word-wrap: break-word !important;"> 提供服务发现和注册，这里主要是管理Broker，NameSrv接受来自Broker的注册，并通过心跳机制来检测Broker服务的健康性； 提供路由功能，集群(这里是指以集群方式部署的NameSrv)中的每个NameSrv都保存了Broker集群(这里是指以集群方式部署的Broker)中整个的路由信息和队列信息。这里需要注意，在NameSrv集群中，每个NameSrv都是相互独立的，所以每个Broker需要连接所有的NameSrv，每创建一个新的topic都要同步到所有的NameSrv上。 </blockquote> </section> </section> </section> </section> </section> </section> Broker：主要是负责消息的存储、传递、查询以及高可用(HA)保证等。其由如下几个子模块（源码总体上也是这么拆分的）构成： <section class="" style="max-width: 100%;font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif;text-align: justify;white-space: normal;background-color: rgb(255, 255, 255);font-size: 16px;letter-spacing: 0px;color: rgb(62, 62, 62);line-height: 1.6;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <section class="" style="max-width: 100%;line-height: 1.6;letter-spacing: 0px;box-sizing: border-box !important;word-wrap: break-word !important;"> <blockquote style="max-width: 100%;color: rgb(51, 51, 51);font-family: -apple-system-font, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", Arial, sans-serif;font-size: 17px;letter-spacing: 0.544px;text-align: justify;white-space: normal;box-sizing: border-box !important;word-wrap: break-word !important;"> remoting，是Broker的服务入口，负责客户端的接入（Producer和Consumer）和请求处理。 client，管理客户端和维护消费者对于Topic的订阅。 store，提供针对存储和消息查询的简单的API（数据存储在物理磁盘）。 HA，提供数据在主从节点间同步的功能特性。 Index，通过特定的key构建消息索引，并提供快速的索引查询服务。 </blockquote> </section> </section> </section> </section> </section> </section> 而从客户端的角度看主要有：Producer、Consumer两个部分。 Producer：消息的生产者，由用户进行分布式部署，消息由Producer通过多种负载均衡模式发送到Broker集群，发送低延时，支持快速失败。 Consumer：消息的消费者，也由用户部署，支持PUSH和PULL两种消费模式，支持集群消费和广播消息，提供实时的消息订阅机制，满足大多数消费场景。 来总结下，整个RocketMQ消息集群就是由NameSrv/Broker、Producer/Consumer组成的。为了让大家更清晰的理解它们之间的关系，我们以一条完整的信息流转为例，来看看RocketMQ消息系统是如何运转的，如下图所示： <img class="" data-croporisrc="/upload/1089cefb06fcf7b7759df7bbcdef30ab.png" data-cropx1="30.51438848920863" data-cropx2="998" data-cropy1="17.949640287769782" data-cropy2="874.1474820143885" data-ratio="0.8853305785123967" data-s="300,640" src="https://mmbiz.qpic.cn/mmbiz_jpg/l89kosVutolicSibQZk2KBYJFDq9uCfiaPZsTuNMaYIss9by1eePkLLZucW3ibtibKrnOYgiaSRokmSu4Dh1UgSfNTsQ/640?wx_fmt=jpeg" data-type="jpeg" data-w="968" style="width: 100%;height: auto;" data-backw="539" data-backh="477" data-before-oversubscription-url="https://mmbiz.qpic.cn/mmbiz_jpg/l89kosVutolicSibQZk2KBYJFDq9uCfiaPZsTuNMaYIss9by1eePkLLZucW3ibtibKrnOYgiaSRokmSu4Dh1UgSfNTsQ/640?wx_fmt=jpeg"> 看到这里相信大家应该对RocketMQ有一个大致的了解了，那么下面我们就具体看看，如何搭建一套生产级的RocketMQ消息集群系统吧！ RocketMQ集群模式 RocketMQ集群部署有多种模式，对于NameSrv来说可以同时部署多个节点，并且这些节点间也不需要有任何的信息同步，这里因为每个NameSrv节点都会存储全量路由信息，在NameSrv集群模式下，每个Broker都需要同时向集群中的每个NameSrv节点发送注册信息，所以这里对于NameSrv的集群部署来说并不需要做什么额外的设置。 而对于Broker集群来说就有多种模式了，这里我先给大家介绍下这几种模式，然后我们再来看看生产级的部署方式是什么： 1）、单个Master模式 一个Broker作为主服务，不设置任何Slave，很显然这种方式风险比较大，存在单节点故障会导致整个基于消息的服务挂掉，所以生产环境不可能采用这种模式。 2）、多Master模式 这种模式的Broker集群，全是Master，没有Slave节点。这种方式的优缺点如下： 优点：配置会比较简单一些，如果单个Master挂掉或重启维护的话对应用是没有什么影响的。如果磁盘配置为RAID10（服务器的磁盘阵列模式，遗忘的同学可以自己查下资料）的话，即使在机器宕机不可恢复的情况下，由于RAID10磁盘本身的可靠性，消息也不会丢失（异步刷盘丢失少量消息，同步刷盘一条不丢），这种Broker的集群模式性能相对来说是最高的。 缺点：就是在单台机器宕机期间，这台机器上未被消费的消息在机器恢复之前是不可以进行消息订阅的，这对消息的实时性会有一些影响。 3）、多Master多Slave模式（异步复制） 在这种模式下Broker集群存在多个Master节点，并且每个Master节点都会对应一个Slave节点，有多对Master-Slave，HA(高可用)之间采用异步复制的方式进行信息同步，在这种方式下主从之间会有短暂的毫秒级的消息延迟。 优点：在这种模式下即便磁盘损坏了，消息丢失的情况也非常少，因为主从之间有信息备份；并且，在这种模式下消息的实时性也不会受影响，因为Master宕机后Slave可以自动切换为Master模式，这样Consumer仍然可以通过Slave进行消息消费，而这个过程对应用来说则是完全透明的，并不需要人工干预；另外，这种模式的性能与多Master模式几乎差不多。 缺点：如果Master宕机，并且在磁盘损坏的情况下，会丢失少量的消息。 4）、多Master多Slave模式（同步复制） 这种模式与3）差不多，只是HA采用的是同步双写的方式，即主备都写成功后，才会向应用返回成功。 优点：在这种模式下数据与服务都不存在单点的情况，在Master宕机的情况下，消息也没有延迟，服务的可用性以及数据的可用性都非常高。 缺点：性能相比于异步复制来说略低一些（大约10%）；另外一个缺点就是相比于异步复制，目前Slave备机还暂时不能实现自动切换为Master，可能后续的版本会支持Master-Slave的自动切换功能。 生产级RocketMQ集群 综合考虑以上集群模式的优缺点，在实际生产环境中目前基于RocketMQ消息集群的部署方式基本都是采用多Master多Slave（异步复制）这种模式，作者目前所在公司的生产环境的Rocket消息系统也是采用这种模式进行部署的。 以下为目前作者所在公司的实际部署结构： <img class="" data-backh="265" data-backw="556" data-before-oversubscription-url="https://mmbiz.qpic.cn/mmbiz_png/l89kosVutonU4QwBmwAvs5jDqhNicDibCRFBsibJjdDiaCjujIecCERg4zO6b7Kmz5pIM6BgGDbCxibV3D1SW2A8mibA/0?wx_fmt=png" data-copyright="0" data-ratio="0.476221928665786" data-s="300,640" src="/upload/b2bce4ec87470de3bdbd69f25c3316c9.png" data-type="png" data-w="1514" style="width: 100%;height: auto;"> 在以上实践中，部署了3个NameSrv节点，Broker采用2主2从的异步复制模式进行集群部署。 为了更好地理解RocketMQ的集群运行原理，接下来我们以4台虚拟机来模拟上述集群的搭建过程，假设这4台机器的IP分别为： <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <blockquote style="line-height: inherit;display: block;padding: 15px 15px 15px 1rem;font-size: 0.9em;margin: 1em 0px;color: rgb(129, 145, 152);border-left: 6px solid rgb(220, 230, 240);background: rgb(242, 247, 251) none repeat scroll 0% 0%;overflow: auto;overflow-wrap: normal;word-break: normal;"> 10.211.55.4 10.211.55.5 10.211.55.6 10.211.55.7 </blockquote> </section> 首先确保几台虚拟机上安装了JDK1.8+: <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="shell language-shell hljs" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" https://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.tar.gz JAVA_HOME=/opt/java/jdk1.8.0_191 CLASSPATH=$JAVA_HOME/lib/ PATH=$PATH:$JAVA_HOME/bin export PATH JAVA_HOME CLASSPATH </code></pre> </section> 其次我们打算通过RocketMQ的源码进行编译，因为源码是基于Maven开发的Java工程，所以我们需要安装下Maven环境: <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="shell language-shell hljs" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">wget https://archive.apache.org/dist/maven/binaries/apache-maven-3.2.1-bin.tar.gz export MAVEN_HOME=/opt/apache-maven-3.2.1 export PATH=${PATH}:${MAVEN_HOME}/bin #配置阿里云镜像 <mirror>        <id>nexus-aliyun</id>        <mirrorOf>central</mirrorOf>        <name>Nexus aliyun</name>        <url>http://maven.aliyun.com/nexus/content/groups/public</url> </mirror> </code></pre> </section> 如果多台机器，没有必要依次下载，可以通过远程复制命令完成机器间的拷贝: <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="shell language-shell hljs" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">scp -r /opt/apache-maven-3.2.1/ root@10.211.55.6:/opt/ </code></pre> </section> 完成后，我们就可以在主机的指定目录下载RocketMQ的源码发布包（这里为4.3.2版本）进行编译了： <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="shell language-shell hljs" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">#download-4.3.2源码准备编译 wget http://mirror.bit.edu.cn/apache/rocketmq/4.3.2/rocketmq-all-4.3.2-source-release.zip  mvn -Prelease-all -DskipTests clean install -U cd /opt/rocketmq-all-4.3.2/distribution/target/apache-rocketmq </code></pre> </section> 以上动作需要在各个机器节点也同步操作！编译完成后，我们来规划下如何利用这4台虚拟机来实现“3个NameSrv节点、2组Master-Slave Broker集群”的效果。 <img class="" data-backh="130" data-backw="556" data-before-oversubscription-url="http://mmbiz.qpic.cn/mmbiz_png/l89kosVutommu1rlC8NOp20mQG7xq7jRqOPOUxZPDt9Y65Xv4a9f81iaPJYSBlWeTlpoMn7IgKVyHIQ8NV58g1Q/0?wx_fmt=png" data-ratio="0.23444283646888567" data-s="300,640" src="/upload/a5c60b981379b450b3d9131c2401720c.png" data-type="png" data-w="1382" style="width: 100%;height: auto;"> 因为本地机器资源原因，我们通过虚拟机混部的方式来实现上述集群的效果，4台机器的3台会分别作为NameSrv节点，而对于Broker集群则两两组合，如上表所示！ 按照上述规划，接下来我们就来看下具体的配置方式： 1）Master-Broker-a的配置 #创建数据存储目录 <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="hljs perl" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">[root@bogon local]# mkdir -p /usr/local/rocketmq/data/store [root@bogon local]# mkdir -p /usr/local/rocketmq/data/store/commitlog [root@bogon local]# mkdir -p /usr/local/rocketmq/data/store/consumequeue [root@bogon local]# mkdir -p /usr/local/rocketmq/data/store/index [root@bogon local]# mkdir -p /usr/local/rocketmq/data/store/checkpoint [root@bogon local]# mkdir -p /usr/local/rocketmq/data/store/abort </code></pre> </section> #切换服务器目录为对应的配置文件目录 <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="hljs bash" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">cd /opt/rocketmq-all-4.3.2/distribution/target/apache-rocketmq/conf cd 2m-2s-async //这里因为我们采用的是异步复制模式，所以需要编辑2m-2s-async中的配置文件 </code></pre> </section> <span style="max-width: 100%;font-family: Avenir, -apple-system-font, 微软雅黑, sans-serif;letter-spacing: 0.544px;color: rgb(137, 135, 145);font-size: 16px;box-sizing: border-box !important;word-wrap: break-word !important;overflow-wrap: break-word !important;"> #编辑Broker集群配置文件 [root@bogon 2m-2s-async]# vim broker-a.properties <section class="output_wrapper" style="font-size: 16px;color: rgb(62, 62, 62);line-height: 1.6;word-spacing: 0px;letter-spacing: 0px;font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;background-image: linear-gradient(90deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%), linear-gradient(360deg, rgba(50, 0, 0, 0.05) 3%, rgba(0, 0, 0, 0) 3%);background-size: 20px 20px;background-position: center center;"> <pre style="font-size: inherit;color: inherit;line-height: inherit;margin: 0px;padding: 0px;"><code class="hljs ini" style="overflow-wrap: break-word;margin: 0px 2px;line-height: 18px;font-size: 14px;font-weight: normal;word-spacing: 0px;letter-spacing: 0px;font-family: Consolas, Inconsolata, Courier, monospace;border-radius: 0px;color: rgb(169, 183, 198);background: rgb(40, 43, 46) none repeat scroll 0% 0%;overflow-x: auto;padding: 0.5em;display: block !important;white-space: pre !important;word-wrap: normal !important;word-break: normal !important;overflow: auto !important;">#broker所属哪个集群，默认【DefaultCluster】 brokerClusterName=DefaultCluster #broker 实列名称，主从关系的需要保持名称一致 brokerName=broker-a #brokerId，必须是大等于0的整数，0表示Master，>0表示Slave brokerId=0 #删除文件的时间点，默认为凌晨4点 deleteWhen=04 #文件保留时间，默认为48小时 fileReservedTime=48 #-ASYNC_MASTER 异步复制Master #-SYNC_MASTER  同步双写Master #-SLAVE <span class="hljs-attr" style="font-size: inherit;line-height: inherit;margin: 0px;padding: 0px;color: r

文章列表