Java底层知识点、源码解读，技术栈相关原理知识点、工具解读最佳实践、功能点实战，问题排查，开发技巧等.zip

j360-tools Java知识点持续更新 [](https://www.apache.org/licenses/LICENSE-2.0.html) [](https://travis-ci.org/xuminwlt/j360-tools) **Java体系微服务架构和运维优化, 学而思, 思而学, 分享一下工作中使用的技术点, 会持续更新** ## 书单篇 <a href="https://github.com/xuminwlt/j360-book-list">我的书单: 2019夏至篇</a> ## 基础篇 1. <a href="#1.1">在String中使用KMP算法计算部分操作</a> 2. <a href="#1.1">JMH验证</a> 3. <a href="#1.3">线程池如何用好/shutdown pool时的规则, shutdown() && shutdownnow(), kill和钩子引用</a> 4. <a href="#1.4">二叉堆实现有序队列</a> 5. <a href="#1.5">解读ThreadLocal</a> 6. <a href="#1.6">Java中的排序场景,Collections.sort, TreeMap</a> 7. <a href="#1.7">线程生命周期各状态在jstack中的解读</a> 8. <a href="#1.8">String.intern, Long, Integer等对象池在jvm中使用</a> 9. <a href="#1.9">finalize,phantomReference使用</a> 10. <a href="#1.10">验证hash、一致性hash的分布(murmurhash)</a> 11. <a href="#1.11">算法:sort/search/rate limit/sliding window</a> 12. <a href="#1.12">索引,B-tree、invert index</a> 13. <a href="#1.13">对象头、指针、锁、类</a> 14. <a href="#1.14">SecureRandom seed相关</a> 15. <a href="#1.15">异常</a> 16. <a href="#1.16">异步 & Future, 并发异步读提升接口性能</a> 17. <a href="#1.17">ForkJoin工作原理</a> 18. <a href="#1.18">nio对照阻塞io写法,Selector工作原理</a> ## 提高篇 1. 事务,分布式事务,Innodb实现 - <a href="./docs/Transaction.md">事务,分布式事务,Innodb实现,分布式事务案例分析</a> - <a href="./docs/Transaction-Fescar.md">分布式事务Alibaba Fescar实现</a> 2. 一致性hash分片、扩容与缩服 3. CAP 4. redis & cluster 5. JVM <a href="VmFlagsFinal.md">VMFlags</a>, Hotspot/JPDA/JVMTI相关 参考: - https://www.ibm.com/developerworks/cn/java/j-lo-jpda3/index.html - http://calvin1978.blogcn.com/articles/jvmoption-7.html 6. Netty/Selector在工程中的高效使用 <a href="./docs/netty.md">Netty案例</a> 7. <a href="./docs/log4j2.md">Log4j2的高效使用</a> 8. <a href="./docs/HikariCP.md">HikariCP 解读、译文</a> 9. Web服务会话管理实现 ## 运维篇 1. coredump segmentfault https://www.cnblogs.com/lidabo/p/5014710.html 2. 句柄、TCP/内核相关调整 ulimit -n 3. netstat 状态解读 4. crontab 简单搞定定时器,备份日志、mysql、任务执行调度 5. Mysql连接池 6. Java服务化shell 7. 日志利器sed、awk 8. <a href="docs/nginx.md">Nginx常用配置及优化手段</a> 9. <a href="docs/redis.md">redis: master/slave,cluster</a> ## 常用中间件工具篇 1. elasticsearch 2. canal 3. flume/fluentd 4. <a href="./docs/TRACING.md">zipkin/brave/Skywalking</a> 5. Azkaban 6. Apollo 7. Zabbix/Kibana/Grafana 8. ActiveMQ 9. <a href="./docs/rocketmq.md">RocketMQ v4.3.0</a> 10. Dubbo 11. Sharding-Sphere 12. Saga <a href="https://github.com/apache/servicecomb-pack">servicecomb-pack</a> 13. Kafka 14. <a href="./docs/seata.md">Seata</a> ## 容器篇 1. docker/docker compose 2. k8s 3. istio ## 书单 https://github.com/xuminwlt/j360-book-list ## 业务篇 1. Timeline 2. 消息、推送系统 3. 用户 4. 支付 5. 计数器 ## 问题排查篇 1. 慢接口 2. GC 3. Mysql死锁 ## 开发小技巧篇 1. 分布式锁 2. Master-Slave 3. 限流 4. 热点数据 ------------------------------------------------------------------------------- 基础篇 ------------------------------------------------------------------------------- ### <a name="1.1">1. KMP算法+JMH验证</a> ``` # Measurement: 2 iterations, 1 s each # Timeout: 10 min per iteration # Threads: 1 thread, will synchronize iterations # Benchmark mode: Throughput, ops/time # Benchmark: me.j360.tools.ToolsBenchmark.indexOfKMPLongText ... Result "me.j360.tools.ToolsBenchmark.indexOfStringLongText": 1171034.703 ops/ms # Run complete. Total time: 00:00:18 Benchmark Mode Cnt Score Error Units ToolsBenchmark.indexOfKMP thrpt 2 22165.252 ops/ms ToolsBenchmark.indexOfKMPLongText thrpt 2 1343.742 ops/ms ToolsBenchmark.indexOfString thrpt 2 2957587.750 ops/ms ToolsBenchmark.indexOfStringLongText thrpt 2 1171034.703 ops/ms ``` ### <a name="1.3">3. 理解线程池,用好线程池</a> 从使用到深入了解自定义线程池ThreadPoolExecutor,先了解最完整的构造方法参数,一共7个参数 ``` /** * Creates a new {@code ThreadPoolExecutor} with the given initial * parameters. * * @param corePoolSize the number of threads to keep in the pool, even * if they are idle, unless {@code allowCoreThreadTimeOut} is set * @param maximumPoolSize the maximum number of threads to allow in the * pool * @param keepAliveTime when the number of threads is greater than * the core, this is the maximum time that excess idle threads * will wait for new tasks before terminating. * @param unit the time unit for the {@code keepAliveTime} argument * @param workQueue the queue to use for holding tasks before they are * executed. This queue will hold only the {@code Runnable} * tasks submitted by the {@code execute} method. * @param threadFactory the factory to use when the executor * creates a new thread * @param handler the handler to use when execution is blocked * because the thread bounds and queue capacities are reached * @throws IllegalArgumentException if one of the following holds:<br> * {@code corePoolSize < 0}<br> * {@code keepAliveTime < 0}<br> * {@code maximumPoolSize <= 0}<br> * {@code maximumPoolSize < corePoolSize} * @throws NullPointerException if {@code workQueue} * or {@code threadFactory} or {@code handler} is null */ public ThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) { if (corePoolSize < 0 || maximumPoolSize <= 0 || maximumPoolSize < corePoolSize || keepAliveTime < 0) throw new IllegalArgumentException(); if (workQueue == null || threadFactory == null || handler == null) throw new NullPointerException(); this.corePoolSize = corePoolSize; this.maximumPoolSize = maximumPoolSize; this.workQueue = workQueue; this.keepAliveTime = unit.toNanos(keepAliveTime); this.threadFactory = threadFactory; this.handler = handler; } ``` - 参数列表 核心线程数:默认参照cpu的数量 最大线程数:线程池所能容纳的最大线程数 空闲存活时间:非核心线程的空闲存活时间 时间单位 队列实例:任务队列,其中常用的有三种队列，SynchronousQueue,LinkedBlockingDeque,ArrayBlockingQueue 线程工厂:尽量自定义线程工厂,默认DefaultThreadFactory 拒绝策略:默认丢弃,选择jdk自带的四选一策略。 - 内部属性 ctl:记录每个线程的状态字段,使用29+3位的Integer类型记录,当数量更大时,未来会考虑使用AtomicLong类型 - 参数大小特别说明 1. ** 当线程池小于corePoolSize时，新提交任务将创建一个新线程执行任务，即使此时线程池中存在空闲线程。 ** 2. 当线程池达到corePoolSize时，新提交任务将被放入workQueue中，等待线程池中�