JAVA多线程之方法 JOIN详解及实例代码

  join
  public final void join(long millis)throws InterruptedException
  Waits at most millis milliseconds for this thread to die. A timeout of 0 means to wait forever.

package concurrentstudy;
/**
 *
 * @author vma
 */
public class JoinTest {
  public static void main(String[] args) {
    Thread t = new Thread(new RunnableImpl());
    t.start();
    try {
      t.join(1000);
      System.out.println("joinFinish");
    } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
   
    }
  }
}
class RunnableImpl implements Runnable {

  @Override
  public void run() {
    try {
      System.out.println("Begin sleep");
      Thread.sleep(1000);
      System.out.println("End sleep");
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

  }
}

Begin sleep
End sleep
joinFinish

 public void run() {
    try {
      System.out.println("Begin sleep");
      // Thread.sleep(1000);
      Thread.sleep(2000);
      System.out.println("End sleep");
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

  }

Begin sleep
joinFinish
End sleep

public final void join() throws InterruptedException {
  join(0);
  }

 /**
   * Waits at most <code>millis</code> milliseconds for this thread to 
   * die. A timeout of <code>0</code> means to wait forever. 
   *
   * @param   millis  the time to wait in milliseconds.
   * @exception 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);
    }
  } else {
    while (isAlive()) {
    long delay = millis - now;
    if (delay <= 0) {
      break;
    }
    wait(delay);
    now = System.currentTimeMillis() - base;
    }
  }
  }

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package concurrentstudy;
/**
 *
 * @author vma
 */
public class JoinTest {
  public static void main(String[] args) {
    Thread t = new Thread(new RunnableImpl());
    new ThreadTest(t).start();
    t.start();
    try {
      t.join();
      System.out.println("joinFinish");
    } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
   
    }
  }
}
class ThreadTest extends Thread {

  Thread thread;

  public ThreadTest(Thread thread) {
    this.thread = thread;
  }

  @Override
  public void run() {
    holdThreadLock();
  }

  public void holdThreadLock() {
    synchronized (thread) {
      System.out.println("getObjectLock");
      try {
        Thread.sleep(9000);

      } catch (InterruptedException ex) {
       ex.printStackTrace();
      }
      System.out.println("ReleaseObjectLock");
    }

  }
}

class RunnableImpl implements Runnable {

  @Override
  public void run() {
    try {
      System.out.println("Begin sleep");
      Thread.sleep(2000);
      System.out.println("End sleep");
    } catch (InterruptedException e) {
      e.printStackTrace();
    }


  }
}

getObjectLock
Begin sleep
End sleep
ReleaseObjectLock
joinFinish