父子线程值传递

1.问题描述
父子线程或线程池缓存线程复用时值未传递问题
2.解决方法
引入依赖

<dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>transmittable-thread-local</artifactId>
      <version>2.11.0</version>
</dependency>

2.代码

public class CustomThreadLocal {
    static ThreadLocal<String> threadLocal = new TransmittableThreadLocal<>();
    static ExecutorService pool = TtlExecutors.getTtlExecutorService(Executors.newFixedThreadPool(2));

    public static void main(String[] args) {
        for (int i = 0; i < 2; i++) {
            int j = i;
            pool.execute(new Thread(()->{
                CustomThreadLocal.threadLocal.set("xionger"+j);
                new Service().call();
            }));
        }
    }

    static class Service{
         void call(){
            CustomThreadLocal.pool.execute(()->{
                System.out.println(Thread.currentThread().getName()+"-service-"+CustomThreadLocal.threadLocal.get());
                new Dao().call();});
        }
    }
    static class Dao{
        void call(){
            System.out.println(Thread.currentThread().getName()+"-dao-"+CustomThreadLocal.threadLocal.get());
        }
    }
}

控制台：

pool-1-thread-1-service-xionger0
pool-1-thread-2-service-xionger1
pool-1-thread-2-dao-xionger1
pool-1-thread-1-dao-xionger0

由此可见，从Service的call方法成功将自定义线程的值传递到了Dao类