今天看了看Java并发程序，写一写入门程序，并设置了线程的优先级。

class Elem implements Runnable{ public static int id = 0; private int cutDown = 5; private int priority; public void setPriority(int priority){ this.priority = priority; } public int getPriority(){ return this.priority; } public void run(){ Thread.currentThread().setPriority(priority); int threadId = id++; while(cutDown-- > 0){ double d = 1.2; while(d < 10000) d = d + (Math.E + Math.PI)/d; System.out.println("#" + threadId + "(" + cutDown + ")"); } }}public class Basic { public static void main(String args[]){ for(int i = 0; i < 10; i++){ Elem e = new Elem(); if(i == 0 ) e.setPriority(Thread.MAX_PRIORITY); else e.setPriority(Thread.MIN_PRIORITY); Thread t = new Thread(e); t.start(); } }}

由于机器很强悍，所以先开始并没看到并发的效果，感觉是按顺序执行的，所以在中间加了浮点数的运算来延迟时间。

当然，main函数里面可以用Executors来管理线程。

import java.util.concurrent.*;class Elem implements Runnable{ public static int id = 0; private int cutDown = 5; private int priority; public void setPriority(int priority){ this.priority = priority; } public int getPriority(){ return this.priority; } public void run(){ Thread.currentThread().setPriority(priority); int threadId = id++; while(cutDown-- > 0){ double d = 1.2; while(d < 10000) d = d + (Math.E + Math.PI)/d; System.out.println("#" + threadId + "(" + cutDown + ")"); } }}public class Basic { public static void main(String args[]){// for(int i = 0; i < 10; i++){// Elem e = new Elem();// if(i == 0 )// e.setPriority(Thread.MAX_PRIORITY);// else// e.setPriority(Thread.MIN_PRIORITY);// Thread t = new Thread(e);// t.start();// } ExecutorService exec = Executors.newCachedThreadPool(); for(int i = 0; i < 10; i++){ Elem e = new Elem(); if(i == 0 ) e.setPriority(Thread.MAX_PRIORITY); else e.setPriority(Thread.MIN_PRIORITY); exec.execute(e); } exec.shutdown(); }}