一.继承Thread ,重写run

class MyThread extends Thread{@Overridepublic void run() {//这里的内容就是该线程要完成的工作while(true) {System.out.println("hello thread");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}
}
public class Demo1 {public static void main(String[] args) throws InterruptedException {Thread t = new MyThread();t.start();//执行run方法中的逻辑while(true) {System.out.println("hello main");Thread.sleep(1000);}}
}

运行结果: 

每秒中输出一次可能是main开头,也可能是thread开头,说明多个线程的调度顺序是"无序的",在操作系统内部也称为"抢占执行".

二.实现Runable,重写run,把Runable实例传入Thread中

class MyRunnable implements Runnable {@Overridepublic void run() {System.out.println("hello thread");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}
}
public class Demo2 {public static void main(String[] args) throws InterruptedException {Thread t = new Thread(new MyRunnable());t.start();while (true) {System.out.println("hello main");Thread.sleep(1000);}}
}

三.针对一的变形,使用匿名内部内,继承Thread 并重写run.

public class Demo3 {public static void main(String[] args) {new Thread() {@Overridepublic void run() {while (true) {System.out.println("hello thread");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}}.start();//t.start();while (true) {System.out.println("hello main");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}
}

1.创建一个子类(没有名字).

2.同时也创建了这个子类的实例 .

3.重写run方法.

四.匿名内部类,针对Runnable

public class Demo4 {public static void main(String[] args) {Thread t = new Thread(new Runnable() {//此处匿名内部类,只针对Runnable和Thread没有关系,只是把Runnable作为参数传入到Thread的构造方法中@Overridepublic void run() {while(true) {System.out.println("hello thread");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}});t.start();while (true) {System.out.println("hello main");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}
}

1.创建新的类,实现Runnable,名字是匿名的

2.创建了这个类的实例(一次性的)

3.重写run方法.

五.使用lambda 表达式

public class Demo5 {public static void main(String[] args) {Thread t = new Thread(() -> {while (true) {System.out.println("hello thread");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}});t.start();while (true) {System.out.println("hello main");try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}}}
}