一图理解ThreadLocal、ThreadLocalMap和Thread的关系

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 ​编辑

ThreadLocalMap拥有静态内部类Entry，可以实例化多个；

每个Entry的key就是当前线程使用的ThreadLocal引用，值是你使用ThreadLocal  set的值

附上测试代码

public static void main(String[] args) {
        final ThreadLocal local = new ThreadLocal();
        Random random = new Random();

        for (int i = 0; i < 5; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    Thread thread = Thread.currentThread();

                    int x = random.nextInt();
                    System.out.println(thread.getName()+ " : " + x);
                    local.set(x);
                    System.out.println(thread.getName() + " : " + local.get());

                    try {
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }

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