Runnable与Callable区别

Posted hkplus

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了Runnable与Callable区别相关的知识,希望对你有一定的参考价值。

相同点:

  1. 两者都是接口;(废话)
  2. 两者都可用来编写多线程程序;
  3. 两者都需要调用Thread.start()启动线程;

 

不同点:

  1. 两者最大的不同点是:实现Callable接口的任务线程能返回执行结果;而实现Runnable接口的任务线程不能返回结果;
  2. Callable接口的call()方法允许抛出异常;而Runnable接口的run()方法的异常只能在内部消化,不能继续上抛;

 

注意点:

  • Callable接口支持返回执行结果,此时需要调用FutureTask.get()方法实现,此方法会阻塞主线程直到获取‘将来’结果;当不调用此方法时,主线程不会阻塞!

 

Callable工作的Demo:

package com.callable.runnable;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

/**
 * Created on 2016/5/18.
 */
public class CallableImpl implements Callable<String> {

    public CallableImpl(String acceptStr) {
        this.acceptStr = acceptStr;
    }

    private String acceptStr;

    @Override
    public String call() throws Exception {
        // 任务阻塞 1 秒
        Thread.sleep(1000);
        return this.acceptStr + " append some chars and return it!";
    }


    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Callable<String> callable = new CallableImpl("my callable test!");
        FutureTask<String> task = new FutureTask<>(callable);
        long beginTime = System.currentTimeMillis();
        // 创建线程
        new Thread(task).start();
        // 调用get()阻塞主线程,反之,线程不会阻塞
        String result = task.get();
        long endTime = System.currentTimeMillis();
        System.out.println("hello : " + result);
        System.out.println("cast : " + (endTime - beginTime) / 1000 + " second!");
    }
}

 

Runnable的Demo

package com.callable.runnable;

/**
 * Created on 2016/5/18.
 */
public class RunnableImpl implements Runnable {

    public RunnableImpl(String acceptStr) {
        this.acceptStr = acceptStr;
    }

    private String acceptStr;

    @Override
    public void run() {
        try {
            // 线程阻塞 1 秒,此时有异常产生,只能在方法内部消化,无法上抛
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        // 最终处理结果无法返回
        System.out.println("hello : " + this.acceptStr);
    }


    public static void main(String[] args) {
        Runnable runnable = new RunnableImpl("my runable test!");
        long beginTime = System.currentTimeMillis();
        new Thread(runnable).start();
        long endTime = System.currentTimeMillis();
        System.out.println("cast : " + (endTime - beginTime) / 1000 + " second!");
    }
}

 

转自


以上是关于Runnable与Callable区别的主要内容,如果未能解决你的问题,请参考以下文章

Runnable与Callable区别

多线程编程之Runnable与Callable区别

Java多线程Runnable与Callable区别与拓展

Callable与Runnable的区别及其在JDK源码中的应用

java中runnable和callable的区别

Callable接口