Java实现多线程的四种方式

一、继承Thread类，重写run方法

public class newThread extends Thread {public void run(){System.out.println(Thread.currentThread().getName());}public static void main(String[] args) {newThread T = new newThread();//自定义线程TThread t1 = new Thread(T,"线程t1");T.setName("线程T");T.start();try {T.join();//保证线程T在T1前执行} catch (InterruptedException e) {}t1.start();}}

二、实现Runnable接口，重写run方法，通过new Thread启动start方法

public class newRunnable implements Runnable{public void run() {System.out.println(Thread.currentThread().getName());}public static void main(String[] args) throws InterruptedException{newRunnable T = new newRunnable();Thread t1 = new Thread(T,"线程t1");Thread t2 = new Thread(T,"线程t2");t1.start();t2.start();}}

三、通过Callable和FutureTask创建线程

步骤：

一、创建实现Callable接口的实现类，并实现call方法

二、创建实现Callable接口的实现类的对象A、创建FutureTask的对象B，B封装了A中call方法的返回值

三、将B作为Thread对象的target，启动线程

四、调用B的get方法来获取子线程执行结束的返回值

import java.util.concurrent.Callable;import java.util.concurrent.FutureTask;public class CallableFutureTask {public static void main(String[] args){Callable<Object> ca = new callable<Object>();FutureTask<Object> fu = new FutureTask<Object>(ca);Thread t1 = new Thread(fu,"线程t1");t1.start();//fu.get(timeout, unit);}}class callable<Object> implements Callable<Object>{public Object call() throws Exception {System.out.println(Thread.currentThread().getName());return null;}}

四、通过线程池创建线程

import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class newThreadpool {private static int poolnum = 2;public static void main(String[] args){ExecutorService pool = Executors.newFixedThreadPool(poolnum);runnable T = new runnable();Thread t1 = new Thread(T,"线程t1");Thread t2 = new Thread(T,"线程t2");Thread t3 = new Thread(T,"线程t3");pool.execute(t1);pool.execute(t2);pool.execute(t3);//超过线程池数量则不会运行、线程的运行不受加入顺序的影响pool.shutdown();}}class runnable implements Runnable{public void run(){System.out.println(Thread.currentThread().getName());}}