java - run() 方法未使用 start() 执行

Question

我只想使用 join() 和 isAlive 函数。我创建了 4 个线程并在构造函数中初始化它们。我使用 start 方法启动线程。它应该调用 run() 但 run 方法没有执行。难道我做错了什么。请告诉我。预先感谢您。

  class MultiThreads implements Runnable {

    String name;
    Thread t;

    MultiThreads(String tname) {
        name=tname;
        t=new Thread(this.name);
        System.out.println("Thread name: " + t);
        t.start();              //executing run()
    }

    public void run(){

       try{
         for(int i=1;i<11;i++){
            System.out.println("Thread-"+name+ ": " + i);
            t.sleep(500);           
            }
       }catch(Exception ie){
           System.out.println("An error has occurred");
        }
    }
 }

public class JoinAlive {

    public static void main(String args[]) {

        //Creating New Threads by calling constructor.

        MultiThreads t1=new MultiThreads("One");``
        MultiThreads t2=new MultiThreads("Two");
        MultiThreads t3=new MultiThreads("Three");
        MultiThreads t4=new MultiThreads("Four");

        System.out.println();

        System.out.println("Thread-One active: " + t1.t.isAlive());
        System.out.println("Thread-Two active: " + t2.t.isAlive());
        System.out.println("Thread-Three active: " + t3.t.isAlive());
        System.out.println("Thread-Four active: " + t4.t.isAlive());

       try{
           System.out.println();
           System.out.println(" Waiting for One");
           t1.t.join();
           System.out.println(" Waiting for Two");
           t2.t.join();
         }catch(InterruptedException ie){
             System.out.println("An error occurred");
          }

          System.out.println();

          System.out.println("Thread-One active: " + t1.t.isAlive());
          System.out.println("Thread-Two active: " + t2.t.isAlive());
          System.out.println("Thread-Three active: " + t3.t.isAlive());
          System.out.println("Thread-Four active: " + t4.t.isAlive());
     }
 }

Answer 1

t=new Thread(this.name); 就是问题所在。
您为线程指定了名称，但没有提供关联的目标 Runnable 实例。

只需使用这个构造函数:

public Thread(Runnable target, String name) 

这样:

t=new Thread(this,this.name);