前言
之前我们使用多线程要么是继承Thread类，要么是实现Runnable接口，然后重写一下run()方法即可。
但是只有的话如果有死锁、对共享资源的访问和随时监控线程状态就不行了，于是在Java5之后就有了Callable接口。
简单的实现有返回值的线程
代码如下：CallableFuture类
java多线程（二）有返回值的多线程
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package top.crosssoverjie.study.Thread;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class CallableFuture {
public static void main(String[] args) {
//创建一个线程池
ExecutorService pool = Executors.newFixedThreadPool(3) ;
//创建三个有返回值的任务
CallableTest2 c1 = new CallableTest2("线程1") ;
CallableTest2 c2 = new CallableTest2("线程2") ;
CallableTest2 c3 = new CallableTest2("线程3") ;
Future f1 = pool.submit(c1) ;
Future f2 = pool.submit(c2) ;
Future f3 = pool.submit(c3) ;
try {
System.out.println(f1.get().toString());
System.out.println(f2.get().toString());
System.out.println(f3.get().toString());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}finally{
pool.shutdown();
}
}
}