java 多线程（ThreadPoolExecutor）

ThreadPoolExecutor是常用的java线程池实现，之前的项目中也一直有用到，本文记录两个基本的例子和参数设置。

例子1：

public class Thread1 {
    public void ThreadOperation(){
        BlockingQueue queue = new LinkedBlockingQueue();
        ThreadPoolExecutor executer 
            = new ThreadPoolExecutor(3,6,1,TimeUnit.DAYS,queue);
        
        for(int i = 0; i < 10; i++){
            executer.execute(new Runnable(){

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    System.out.println("execute:");
                }
            });
           
        executer.shutdown();
    }
}

例子2：

public class Thread2 {
    
    class MyFactory implements ThreadFactory{

        @Override
        public Thread newThread(Runnable r) {
            // TODO Auto-generated method stub
            System.out.println("newThread");
            Thread t = new Thread(r);
            t.setName("Fredric");
            return t;
        }    
    }
    
    public void ThreadOperation(){
        BlockingQueue queue = new LinkedBlockingQueue(4);//特地限制了缓存队列的大小
        ThreadPoolExecutor executor 
            = new ThreadPoolExecutor(3,//初始线程数
                    6,//当缓存满时创建的最大线程数
                    100,//多余线程等待任务的时间
                    TimeUnit.MILLISECONDS,//时间的单位
                    queue,
                    new MyFactory());
        
        for(int i = 0; i < 10; i++){
            executor.execute(new Runnable(){

                @Override
                public void run() {
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println("executer"+
                            Thread.currentThread().getName());
                }    
            });
        }
        
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        }
        
        for(int i = 0; i < 5; i++){
            executor.execute(new Runnable(){

                @Override
                public void run() {
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println("executer "+" next "+
                            Thread.currentThread().getName());
                }    
            });
        }        
        executor.shutdown();        
    }
}

第二个例子证明参数的使用，其打印如下：

newThread
newThread
newThread //系统启动时的核心线程 3个
newThread
newThread
newThread //当缓存队列满时，增加线程至 10个
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric
executerFredric 
newThread
newThread
newThread //超时后，新增的3个线程被销毁，因此被重新创建
executer next Fredric
executer next Fredric
executer next Fredric
executer next Fredric
executer next Fredric