詳解Java多線程中join方法的具體使用 實(shí)例代碼解析

package CSDN;
public class TestJoin {
 
 public static void main(String[] args) throws InterruptedException {
  // TODO Auto-generated method stub
  ThreadTest t1=new ThreadTest("A");
  ThreadTest t2=new ThreadTest("B");
  t1.start();
  t2.start();
 }
 
 
}
class ThreadTest extends Thread {
 private String name;
 public ThreadTest(String name){
  this.name=name;
 }
 public void run(){
  for(int i=1;i<=5;i++){
    System.out.println(name+"-"+i);
  }  
 }
}

package CSDN;
public class TestJoin {
 
 public static void main(String[] args) throws InterruptedException {
  // TODO Auto-generated method stub
  ThreadTest t1=new ThreadTest("A");
  ThreadTest t2=new ThreadTest("B");
  t1.start();
  t1.join();
  t2.start();
 }
}

    /**
     * Waits for this thread to die.
     *
     * <p> An invocation of this method behaves in exactly the same
     * way as the invocation
     *
     * <blockquote>
     * {@linkplain #join(long) join}{@code (0)}
     * </blockquote>
     *
     * @throws  InterruptedException
     *          if any thread has interrupted the current thread. The
     *          <i>interrupted status</i> of the current thread is
     *          cleared when this exception is thrown.
     */
    public final void join() throws InterruptedException {
        join(0);            //join()等同于join(0)
    }
    /**
     * Waits at most {@code millis} milliseconds for this thread to
     * die. A timeout of {@code 0} means to wait forever.
     *
     * <p> This implementation uses a loop of {@code this.wait} calls
     * conditioned on {@code this.isAlive}. As a thread terminates the
     * {@code this.notifyAll} method is invoked. It is recommended that
     * applications not use {@code wait}, {@code notify}, or
     * {@code notifyAll} on {@code Thread} instances.
     *
     * @param  millis
     *         the time to wait in milliseconds
     *
     * @throws  IllegalArgumentException
     *          if the value of {@code millis} is negative
     *
     * @throws  InterruptedException
     *          if any thread has interrupted the current thread. The
     *          <i>interrupted status</i> of the current thread is
     *          cleared when this exception is thrown.
     */
    public final synchronized void join(long millis) throws InterruptedException {
        long base = System.currentTimeMillis();
        long now = 0;
 
        if (millis < 0) {
            throw new IllegalArgumentException("timeout value is negative");
        }
 
        if (millis == 0) {
            while (isAlive()) {
                wait(0);           //join(0)等同于wait(0)，即wait無限時(shí)間直到被notify
            }
        } else {
            while (isAlive()) {
                long delay = millis - now;
                if (delay <= 0) {
                    break;
                }
                wait(delay);
                now = System.currentTimeMillis() - base;
            }
        }
    }

package CSDN;
 
public class TestJoin {
 
 public static void main(String[] args) throws InterruptedException {
  // TODO Auto-generated method stub
  System.out.println(Thread.currentThread().getName()+" start");
  ThreadTest t1=new ThreadTest("A");
  ThreadTest t2=new ThreadTest("B");
  ThreadTest t3=new ThreadTest("C");
  System.out.println("t1start");
  t1.start();
  System.out.println("t2start");
  t2.start();
  System.out.println("t3start");
  t3.start();
  System.out.println(Thread.currentThread().getName()+" end");
 } 
}

package CSDN;
 
public class TestJoin {
 
 public static void main(String[] args) throws InterruptedException {
  // TODO Auto-generated method stub
  System.out.println(Thread.currentThread().getName()+" start");
  ThreadTest t1=new ThreadTest("A");
  ThreadTest t2=new ThreadTest("B");
  ThreadTest t3=new ThreadTest("C");
  System.out.println("t1start");
  t1.start();
  System.out.println("t1end");
  System.out.println("t2start");
  t2.start();
  System.out.println("t2end");
  t1.join();
  System.out.println("t3start");
  t3.start();
  System.out.println("t3end");
  System.out.println(Thread.currentThread().getName()+" end");
 } 
}