java.lang.ThreadLocal<T>

线程容器，给线程绑定一个Object内容，只要线程不变，内容就存在

public class TestThreadLocal {
	public static void main(String[] args) {
		ThreadLocal<Integer> threadLocal = new ThreadLocal<>();
		threadLocal.set(1);
		System.out.println(threadLocal.get());
	}
}

结果

1

public class TestThreadLocal {
	public static void main(String[] args) {
		ThreadLocal<Integer> threadLocal = new ThreadLocal<>();
		threadLocal.set(1);
		new Thread() {
			@Override
			public void run() {
				System.out.println("run: "+ threadLocal.get());
			}
		}.start();
		System.out.println("main: " + threadLocal.get());
	}
}

结果

main: 1
run: null