两个ThreadLocal变量在每个线程中都独自存在,互不干扰。而static变量是两个线程共享的
结果:
public class ThreadLocalSample {
public static void main(String[] args) {
ThreadTest test1 = new ThreadTest(10);
ThreadTest test2 = new ThreadTest(20);
test1.start();
test2.start();
}
}
/**
* 此线程有两个ThreadLocal变量,但是由于ThreadLocal是延迟初始的,
* 所以在debug时可以看到线程名为“线程20”的线程的ThreadLocalMap中没有thLcal2这个entry
* @author mxdba
*
*/
class ThreadTest extends Thread {
public static ThreadLocal<Integer> thLocal = new ThreadLocal<Integer>();
public static ThreadLocal<String> thLocal2 = new ThreadLocal<String>();
public static String ss;
public Integer num;
public ThreadTest(Integer num) {
super("线程" + num);
this.num = num;
}
@Override
public void run() {
Integer n = thLocal.get();
String s=thLocal2.get();
// if(num != 20) {
// String s = thLocal2.get();
// System.out.println("2----"+s);
// }
// System.out.println("thread name="+Thread.currentThread().getName());
if(n == null&&Thread.currentThread().getName().equals("线程10")) {
thLocal.set(num);
// try {
// sleep(10000);
// } catch (InterruptedException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
}
if (s==null){
thLocal2.set(num+"");
}
if (ss==null){
ss=num+"";
}
System.out.println(""+Thread.currentThread()+"------"+"ss------"+ss);
System.out.println(""+Thread.currentThread()+"------"+"1------"+thLocal.get());
System.out.println(""+Thread.currentThread()+"------"+"2------"+thLocal2.get());
}
}
结果:
Thread[线程20,5,main]------ss------20
Thread[线程20,5,main]------1------null
Thread[线程20,5,main]------2------20
Thread[线程10,5,main]------ss------20
Thread[线程10,5,main]------1------10
Thread[线程10,5,main]------2------10
或者:
Thread[线程10,5,main]------ss------10
Thread[线程20,5,main]------ss------10
Thread[线程10,5,main]------1------10
Thread[线程20,5,main]------1------null
Thread[线程10,5,main]------2------10
Thread[线程20,5,main]------2------20