多线程的帮助类（CountDownLatch,Excutor,Executors)

JDK1.5有几个很重要的线程帮助类,对处理线程序很有帮助,他们分别是

CountDownLatch ,Executor ,Executors,下面是他们的简单用法

package com.tang.test;

import java.util.concurrent.CountDownLatch;

public class Job implements Runnable {
	private final CountDownLatch doneSignal;
	private final String name;

	Job(CountDownLatch doneSignal, String name) {
		this.doneSignal = doneSignal;
		this.name = name;
	}

	public void run() {
		try {
			System.out.println(name + " begin to do his work ");
			Thread.sleep(2000);//等待2秒钟,可以理解为工作的时间
			System.out.println(name + " have done his work ");
		} catch (InterruptedException e) {
			e.printStackTrace();
		} finally {
			doneSignal.countDown();//记数器-1
		}
	}
}

 

package com.tang.test;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

public class DoWork {

 private static final int N = 5;

 public static void main(String[] args) {
  CountDownLatch doneSignal = new CountDownLatch(5);//记数器值为5
  Executor e = Executors.newFixedThreadPool(2);//执行者数值为1

  for (int i = 0; i < N; ++i)
   e.execute(new Job(doneSignal, " worker: "+i));//开始执行任务

  try {
   doneSignal.await();//等待计数器中所有任务完成
   System.out.println("all work have done!");
  } catch (InterruptedException e1) {
   e1.printStackTrace();
  }finally{
       System.exit(0);//关闭程序
  }
 }
}

 

 输出结果

 worker: 0 begin to do his work 
 worker: 1 begin to do his work 
 worker: 0 have done his work 
 worker: 1 have done his work 
 worker: 2 begin to do his work 
 worker: 3 begin to do his work 
 worker: 3 have done his work 
 worker: 4 begin to do his work 
 worker: 2 have done his work 
 worker: 4 have done his work 
all work have done!

 修改执行者数目为5, 输出结果为:

 worker: 0 begin to do his work 
 worker: 3 begin to do his work 
 worker: 1 begin to do his work 
 worker: 2 begin to do his work 
 worker: 4 begin to do his work 
 worker: 4 have done his work 
 worker: 3 have done his work 
 worker: 1 have done his work 
 worker: 2 have done his work 
 worker: 0 have done his work 
all work have done!

 

修改执行者数为8,输出结果为:

 worker: 0 begin to do his work 
 worker: 2 begin to do his work 
 worker: 4 begin to do his work 
 worker: 1 begin to do his work 
 worker: 3 begin to do his work 
 worker: 2 have done his work 
 worker: 4 have done his work 
 worker: 3 have done his work 
 worker: 0 have done his work 
 worker: 1 have done his work 
all work have done!