线程Basic

本文参考Think in java,好久没接触线程了，温习一下。

基本的线程可以继承Runnable,这是一个倒计时的小线程，倒数10，9….3,2,1

import java.text.SimpleDateFormat;
import java.util.Date;

import Entry.Main;

public class LiftOff implements Runnable{
    public LiftOff() {
        super();
    }

    //计数值
    private int countDown=10;
    //ID生成
    private static int taskCount=0;
    //线程ID
    private final int ThreadID=taskCount++;


    @Override
    public void run() {
        while(countDown>0) {
            Main.logIndex++;
            System.out.println(Main.logIndex+" "+"[Info]["+System.currentTimeMillis()+"]"+"----"+this.status());
            countDown--;
            Thread.yield();
        }

    }

    //返回线程状态,即countDown的值
     private String status() {
        String status="#"+"Thread["+ThreadID+"]:";
        if(countDown>0) {
            status=status+""+countDown;
        }
        else {
            status="Launch";
        }
        return status;
     }



}

你可以通过以下几个方式来发动线程，我封装在Main方法中，以注释的表达目的：

 package Entry;
import java.util.Date;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import ThreadStash.LiftOff;

public class Main {
    //线程不安全共享变量
    public static long logIndex=0;



    public static void main(String[] args) {
           cacheThreadPool();
    }

    public static void basicTheaad() {
        // TODO Auto-generated method stub
        LiftOff emit=new LiftOff();
        emit.run();
    }
    private static void postToThread() {
        //最后一行语句在任何一个地方都可能打印出来
        Thread t=new Thread(new LiftOff());
        t.start();
        System.out.println("[Info]["+new Date()+"]:"+"PrintedMaybeAnywhere");
    }

    private static void multiThreadExecute(int num) throws NoSuchMethodException, SecurityException {
        for(int i=0;i<num;i++) {
            new Thread(new LiftOff()).start();
        }
        System.out.println("[Info]["+new Date()+"]:"+Main.class.getMethod("multiThreadExecute",Integer.TYPE).getName()+"PrintedMaybeAnywhere");
    }

    private static void cacheThreadPool() {
        //线程池的容量，即能够容纳线程的个数是可变的
        ExecutorService service=Executors.newCachedThreadPool();
        for(int i=0;i<5;i++) {
            service.execute(new LiftOff());
        }
        //shutdown方法放置新的线程加入线程池CachedThreadPool
        service.shutdown();


    }


}

通过调用不同的静态函数，你可以看到一些多线程运行的效果，文中打印方式时间精度为毫秒($10^{-3}$)

  1 [Info][1526142033820]----#Thread[0]:10
2 [Info][1526142033821]----#Thread[1]:10
3 [Info][1526142033821]----#Thread[2]:10
4 [Info][1526142033821]----#Thread[3]:10
5 [Info][1526142033822]----#Thread[4]:10
6 [Info][1526142033822]----#Thread[0]:9
7 [Info][1526142033822]----#Thread[1]:9
8 [Info][1526142033822]----#Thread[2]:9
9 [Info][1526142033823]----#Thread[3]:9
13 [Info][1526142033823]----#Thread[2]:8
12 [Info][1526142033823]----#Thread[1]:8
11 [Info][1526142033823]----#Thread[4]:9
10 [Info][1526142033823]----#Thread[0]:8
17 [Info][1526142033823]----#Thread[4]:8
16 [Info][1526142033823]----#Thread[1]:7
15 [Info][1526142033823]----#Thread[2]:7
14 [Info][1526142033823]----#Thread[3]:8
18 [Info][1526142033823]----#Thread[0]:7
21 [Info][1526142033824]----#Thread[2]:6
19 [Info][1526142033823]----#Thread[4]:7
20 [Info][1526142033823]----#Thread[1]:6
22 [Info][1526142033824]----#Thread[3]:7
23 [Info][1526142033824]----#Thread[2]:5
24 [Info][1526142033824]----#Thread[4]:6
25 [Info][1526142033824]----#Thread[0]:6
26 [Info][1526142033824]----#Thread[1]:5
27 [Info][1526142033824]----#Thread[3]:6
28 [Info][1526142033824]----#Thread[2]:4
29 [Info][1526142033824]----#Thread[0]:5
30 [Info][1526142033824]----#Thread[4]:5
31 [Info][1526142033824]----#Thread[1]:4
32 [Info][1526142033824]----#Thread[3]:5
33 [Info][1526142033824]----#Thread[2]:3
34 [Info][1526142033825]----#Thread[0]:4
36 [Info][1526142033825]----#Thread[1]:3
35 [Info][1526142033825]----#Thread[4]:4
37 [Info][1526142033825]----#Thread[2]:2
38 [Info][1526142033825]----#Thread[3]:4
41 [Info][1526142033825]----#Thread[0]:3
39 [Info][1526142033825]----#Thread[1]:2
44 [Info][1526142033825]----#Thread[0]:2
43 [Info][1526142033825]----#Thread[3]:3
42 [Info][1526142033825]----#Thread[2]:1
40 [Info][1526142033825]----#Thread[4]:3
45 [Info][1526142033825]----#Thread[0]:1
47 [Info][1526142033825]----#Thread[3]:2
46 [Info][1526142033825]----#Thread[1]:1
48 [Info][1526142033825]----#Thread[4]:2
49 [Info][1526142033825]----#Thread[3]:1
50 [Info][1526142033826]----#Thread[4]:1