1.是什么?

• 多線程，是一個(gè)進(jìn)程同一時(shí)間段，執(zhí)行多個(gè)代碼段
• 為了盡可能的利用系統(tǒng)資源。
• 線程執(zhí)行過(guò)程：
  創(chuàng)建 new Thread();
  就緒 new Thread().start();
  阻塞 new Thread().sleep(400);
  運(yùn)行 繼承Thread方法時(shí)extends Thread;需重寫(xiě)的代碼run()方法
  死亡 new Thread().stop();

2.怎么做?

繼承thread類(lèi)

class ThreadExtends extends Thread {
    private String name;
    
    public ThreadExtends(String name){
        this.name = name;
    }
    
    public void run(){ //運(yùn)行
        for(int i=0; i<10; i++){
            System.out.println(this.name+" : "+i);
        }
    }
}

public class testDemo{
    public static void main(String arg[]){
        ThreadExtends thread1 = new ThreadExtends("thread1");//創(chuàng)建
        ThreadExtends thread2 = new ThreadExtends("thread2");
        thread1.start();//就緒
        thread2.start();
    }
}

extends Thread運(yùn)行結(jié)果：

thread1 : 0
thread1 : 1
thread1 : 2
thread1 : 3
thread2 : 0
thread2 : 1
thread2 : 2
thread2 : 3
thread2 : 4
thread2 : 5
thread2 : 6
thread2 : 7
thread2 : 8
thread2 : 9
thread1 : 4
thread1 : 5
thread1 : 6
thread1 : 7
thread1 : 8
thread1 : 9

實(shí)現(xiàn)Runnable接口

class ThreadImplements implements Runnable {
    private String name;
    
    public ThreadImplements(String name){
        this.name = name;
    }
    
    public void run(){
        for(int i=0; i<10; i++){
            System.out.println(this.name+" : "+i);
        }
    }
}

public class testDemo{
    public static void main(String arg[]){
        ThreadImplements threadImp1 = new ThreadImplements("thread1");
        ThreadImplements threadImp2 = new ThreadImplements("thread2");
        Thread thread1 = new Thread(threadImp1);
        Thread thread2 = new Thread(threadImp2);
        thread1.start();
        thread2.start();
    }
}

implements Runnable運(yùn)行結(jié)果：

thread2 : 0
thread2 : 1
thread2 : 2
thread2 : 3
thread2 : 4
thread2 : 5
thread2 : 6
thread2 : 7
thread2 : 8
thread2 : 9
thread1 : 0
thread1 : 1
thread1 : 2
thread1 : 3
thread1 : 4
thread1 : 5
thread1 : 6
thread1 : 7
thread1 : 8
thread1 : 9