详解在Java中如何创建多线程程序

public class threadex extends Thread{
    public void run(){
        for (int i = 0; i < 20; i++) {
            System.out.println("run"+i);
        }
    }
 
}

public class thread {
    public static void main(String[] args) {
        threadex mt=new threadex();
        mt.start();
        for (int i = 0 ; i < 20; i++) {
            System.out.println("main"+i);
        }
    }
 
}

public class threadex2 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            System.out.println(Thread.currentThread().getName()+i);
        }
    }
}

public class thread {
    public static void main(String[] args) {
        //第二种
        threadex2 mt1=new threadex2();
        Thread t=new Thread(mt1);
        t.start();
        for (int i = 0; i < 20; i++) {
            System.out.println(Thread.currentThread().getName()+i);
        }
    }
 
}

public static void main(String[] args) {
        new Thread(){
            public void run(){
                for (int i = 0; i < 20; i++) {
                    System.out.println(Thread.currentThread().getName()+"cs"+i);
                }
            }
        }.start();//Thread-0
 
        //线程的接口Runnable
        //Runnable r=new RunnableImpl();//多态
        Runnable r=new Runnable(){
            //重写run方法，设置线程任务
            public void run(){
                for (int i = 0; i < 20; i++) {
                    System.out.println(Thread.currentThread().getName()+"ff"+i);
                }
            }
        };
        new Thread(r).start();
 
        //简化
        new Thread(new Runnable(){
            //重写run方法，设置线程任务
            public void run(){
                for (int i = 0; i < 20; i++) {
                    System.out.println(Thread.currentThread().getName()+"hj"+i);
                }
            }
        }).start();
    }

//方法一
public class threadfun extends Thread{
    public void run(){
        String name = getName();
        System.out.println(name);
    }
}

public class threadfunmain {
    public static void main(String[] args) {
        threadfun mt = new threadfun();
        mt.start();//Thread-0
        new threadfun().start();//Thread-1
        new threadfun().start();//Thread-2
    }
}

public class threadfun extends Thread{
    public void run(){
        //方法二
        Thread th = Thread.currentThread();
        System.out.println(th);
        String name = getName();
        System.out.println(name);
        //System.out.println(Thread.currentThread().getName());
    }
}

public class threadfunmain {
    public static void main(String[] args) {
        threadfun mt = new threadfun();
        mt.start();//Thread[Thread-0,5,main] Thread-0
        new threadfun().start();//Thread[Thread-1,5,main] Thread-1
        new threadfun().start();//Thread[Thread-2,5,main] Thread-2
        System.out.println(Thread.currentThread().getName());//main
        //主线程中只能用第二种方法获取，因为测试类没有继承Thread类，没有getname方法
    }
}

public class threadfun extends Thread{
    public void run(){
        //设置线程的名称方法一
        System.out.println(Thread.currentThread().getName());
    }
    //设置线程的名称方法二
    threadfun(){}
    threadfun(String name){
        super(name);
    }
}

public class threadfunmain {
    public static void main(String[] args) {
        threadfun mt = new threadfun(); 
        //设置线程的名称方法一
        mt.setName("ess");
        mt.start();
 
        //设置线程的名称方法二
        new threadfun("ff").start();
 
    }
}

//sleep
        for (int i = 0; i < 20; i++) {
            System.out.println(i);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }