package MultiThreading_16;

/*

Callable是Runaable的增强版

call()方法有返回值,可以抛出异常

不过不可以直接作为target

*/

import java.util.concurrent.Callable;

import java.util.concurrent.FutureTask;

/*

Future接口 代表Callable接口call方法返回值

FutureTask实现了Future接口和Runnable接口

*/

public class CallableTest {

public static void main(String[] args) {

CallableTest ct = new CallableTest();

//使用FutureTask包装Callable对象

FutureTask<Integer> task = new FutureTask(

() -> {

int i = 0;

for (; i < 100; i++) {

System.out.println(Thread.currentThread().getName() + " " + i);

}

//call方法有返回值

return i;

}

);

for (int i = 0; i < 100; i++) {

System.out.println(Thread.currentThread().getName() + " " + i);

if (i == 20) {

new Thread(task, "有返回值的线程").start();

}

}

try{

//获取线程返回值

System.out.println(task.get());

}catch (Exception e){

e.printStackTrace();

}

}

}