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/**
* @Author https://www.javastudy.cloud
* @CreateTime 2019/11/01
**/
public class ThreadStudy extends Thread{
/**
* 继承Thread类并且重写run方法,
* 这个方法并不常用,因为一个java类只能继承一个类
*/
@Override
public void run() {
System.out.println("run in sub Thread , Thread name is "+ Thread.currentThread().getName());
}
public static void main(String[] args) {
System.out.println("run in main Thead , Thread name is "+ Thread.currentThread().getName());
ThreadStudy study = new ThreadStudy();
//注意启动线程要用 start()方法
study.start();
try {
//让主线程休眠两秒,让子线程有足够的时间运行
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
运行结果:
这种让一个类直接实现Runnable接口显得有些笨重 实际开发中,经常会用下面匿名类的方式创建线程
/**
* @Author https://www.javastudy.cloud
* @CreateTime 2019/11/01
**/
public class ThreadStudy implements Runnable{
/**
* 实现Runnable接口,
* 这个是常用的方法,因为一个java类可以实现多个接口
*/
@Override
public void run() {
System.out.println("run in sub Thread , Thread name is "+ Thread.currentThread().getName());
}
public static void main(String[] args) {
System.out.println("run in main Thead , Thread name is "+ Thread.currentThread().getName());
//要先new 一个Thread
// 然后把实现Runnable接口的类传入到Thread的构造函数中
ThreadStudy study = new ThreadStudy();
Thread thread = new Thread(study);
//注意启动线程要用 start()方法
thread.start();
try {
//让主线程休眠两秒,让子线程有足够的时间运行
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
使用匿名类来创建线程,这里使用了lambda的写法,也是实际开发中常用的写法
/**
* @Author https://www.javastudy.cloud
* @CreateTime 2019/11/01
**/
public class ThreadStudy {
public static void main(String[] args) {
System.out.println("run in main Thread , Thread name is "+ Thread.currentThread().getName());
// 不用类实现Runnable接口了, 直接这样定义,方便,省事
Runnable runnable = ()-> System.out.println("run in sub Thread, Thread name is "+Thread.currentThread().getName());
// 启动这个线程还是要用Thread来包装下,然后调用Thread.start()方法
Thread thread = new Thread(runnable);
thread.start();
try {
//让主线程休眠两秒,让子线程有足够的时间运行
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
/**
* @Author https://www.javastudy.cloud
* @CreateTime 2019/11/01
**/
public class ThreadStudy {
public static void main(String[] args) {
System.out.println("Run in main Thread, Thread name is "+ Thread.currentThread().getName());
//一句话就可以创建一个线程池下面这种写法线程没有上限,实际开发中不太推荐
// 开发中一般是用下行注释的方法,或者自定义线程池参数
// 常用的还有 Executors.newFixedThreadPool(10);去创建固定10个线程的池子,这个也有弊端,就是等待的队列没有上界
//
ExecutorService service = Executors.newCachedThreadPool();
// 没有返回值的处理
service.submit(()-> System.out.println("Run in sub Thread, Thread name is "+Thread.currentThread().getName()));
// 有返回值的处理,用一个Future 去接收
Future<String> submit = service.submit(() -> "Run in sub Thread with return , Thread name is " + Thread.currentThread().getName());
//输出future里面的值
try {
System.out.println(submit.get());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
运行结果: