通过实现callable的call方法可以完成线程的操作,并且返回一个需要的值
package test1;import java.util.ArrayList;import java.util.List;import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;public class TaskWithResult implements Callable{ // 实现call方法,在方法中输出两句话 public String call() throws Exception { //Thread.sleep(time); System.out.println(Thread.currentThread().getName() + "run..."); Thread.sleep(100); System.out.println(Thread.currentThread().getName() + "test..."); // 返回一个字符串 return Thread.currentThread().getName() + " has executed"; } public static void main(String[] args) throws InterruptedException, ExecutionException { // 用Executors来管理线程 ExecutorService exec = Executors.newCachedThreadPool(); // 用Future来接受返回值 List > results = new ArrayList >(); for(int i=0; i<=10; i++){ // 将返回值放入Future 类型的List中去 results.add(exec.submit(new TaskWithResult())); } // 得到返回值 //System.out.println(results.get(0).get()); exec.shutdown(); }}
输出结果
pool-1-thread-1run...pool-1-thread-2run...pool-1-thread-3run...pool-1-thread-4run...pool-1-thread-5run...pool-1-thread-7run...pool-1-thread-8run...pool-1-thread-9run...pool-1-thread-11run...pool-1-thread-6run...pool-1-thread-10run...pool-1-thread-2test...pool-1-thread-1test...pool-1-thread-4test...pool-1-thread-3test...pool-1-thread-9test...pool-1-thread-8test...pool-1-thread-7test...pool-1-thread-5test...pool-1-thread-10test...pool-1-thread-6test...pool-1-thread-11test...
看出来程序不是顺序运行的,而是将每一个线程分时运行。
可以通过Future的get()来得到返回值
pool-1-thread-1test...pool-1-thread-1 has executedpool-1-thread-3test...pool