用runnable接口创建新线程

public class thread1 {
 public static void main(String args[]){
  new NewThread();             //creat a new thread
  try{
   for(int i=5;i>0;i--)
   {
    System.out.println("main Thread:"+i);
    Thread.sleep(1000);
   }
  }
  catch(InterruptedException e){
   System.out.print("main threa interrupted.");
  }
  System.out.print("main threa exiting.");
 }
}
class NewThread implements Runnable{
 Thread t;
 NewThread(){
  t=new Thread(this,"Demo Thread:"+t);
  System.out.println("chind thread:"+t);
  t.start();       //start the thread
 }
 //@Override
 public void run() {
  // TODO Auto-generated method stub
  try{
   for(int i=5;i>0;i--){
    System.out.println("child thread:"+i);
    Thread.sleep(500);
   }
  }
  catch(InterruptedException e)
  {
   System.out.println("child interrupted.");
  }
  System.out.println("Exiting child interrupted.");
 }
}

 

其中，语句this表明在this对象中要用新的线程调用run（）方法，然后再调用start（）方法。接着run（）方法开始执行线程，这时子线程的for循环开始执行，调用start（）方法后，NewThread的构造函数返回到main（）方法。当主线程被恢复时，它到达for循环。两个线程会继续运行，并共享CPU，直到它们的循环结束。

运行结果如下：

chind thread:Thread[Demo Thread:null,5,main]
child thread:5
main Thread:5
child thread:4
main Thread:4
child thread:3
child thread:2
main Thread:3
child thread:1
Exiting child interrupted.
main Thread:2
main Thread:1
main threa exiting.