线程池

线程池在系统启动时即创建大量空闲的线程，程序将一个Runnable对象传给线程池，线程池就会启动一天线程来执行该对象的run方法 ，放run方法执行结束后，该线程并不会死亡，而是返回线程池中成为空闲状态，等待执行下一个Runnable对象的run方法

还可以控制系统中并发的线程数量

package com.thread;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ThreadPoolTest {
    public static void main(String[] args) {
        ExecutorService poolExecutorService=Executors.newFixedThreadPool(6);
        poolExecutorService.submit(new TestThread());
        poolExecutorService.submit(new TestThread());
        poolExecutorService.shutdown();
    }
}

class TestThread implements Runnable {
    public void run() {
        for (int i = 0; i < 10; i++) {
            System.out.println(Thread.currentThread().getName() + i);
        }
    }
}