Java多线程的在开发中用到的很多,简单总结一下几种写法,分别是继承Thread方法,实现Runnable接口,实现Callable接口;
1.继承Thread方法

class TestThread extends Thread{
    String name;
    public TestThread(String name){
        this.name=name;
    }
    @Override
    public void run() {
        for (int i = 0; i < 6; i++) {
            System.out.println(this.name+":"+i);
        }
    }
}

main方法调用:
Thread启动有两个方法,一个是start()方法,一个是run()方法,但是直接调用run方法时线程不会交替运行,而是顺序执行,只有用start方法时才会交替执行

TestThread tt1 = new TestThread("A");
        TestThread tt2 = new TestThread("B");
        tt1.start();
        tt2.start();

运行结果:
Java多线程的几种写法
2.实现Runnable接口,有多种写法
2.1外部类

class TestRunnable implements Runnable{
    String name;
    public TestRunnable(String name){
        this.name=name;
    }
    @Override
    public void run() {
        for (int i = 0; i < 6; i++) {
            System.out.println(this.name+":"+i);
        }
    }
}

调用:

   TestRunnable tr1 = new TestRunnable("C");
        TestRunnable tr2 = new TestRunnable("D");
        new Thread(tr1).start();
        new Thread(tr2).start();

2.2匿名内部类方式

new Thread(new Runnable() {

            @Override
            public void run() {
                // TODO Auto-generated method stub

            }
        }).start();

2.3 Lamda表达式,jdk1.8,只要是函数式接口,都可以使用Lamda表达式或者方法引用

new Thread(()->{
        for (int i = 0; i < 6; i++) {
            System.out.println(i);
        }
    }).start();

2.4ExecutorService创建线程池的方式

class TestExecutorService implements Runnable{
String name;
public TestExecutorService(String name){
    this.name=name;
}
    @Override
    public void run() {
        for (int i = 0; i < 6; i++) {
            System.out.println(this.name+":"+i);
        }
    }
}

调用:可以创建固定个数的线程池

   ExecutorService pool = Executors.newFixedThreadPool(2);
        TestExecutorService tes1 = new TestExecutorService("E");
        TestExecutorService tes2 = new TestExecutorService("F");
        pool.execute(tes1);
        pool.execute(tes2);
        pool.shutdown();
    运行结果跟2.1差不多

Java多线程的几种写法

3.实现Callable接口,可以返回结果

//Callable<V>提供返回数据,根据需要返回不同类型
class TestCallable implements Callable<String>{
    private int ticket = 5;
    @Override
    public String call() throws Exception {
        for (int i = 0; i < 5; i++) {
            if(this.ticket>0)
                System.out.println("买票,ticket="+this.ticket--);
        }
        return "票卖完了";
    }
}

调用:

Callable<String> tc = new TestCallable();
        FutureTask<String> task = new FutureTask<String>(tc);
        new Thread(task).start();
        try {
            System.out.println(task.get());//获取返回值
        } catch (InterruptedException | ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    运行结果:

Java多线程的几种写法