Java除了用继承Thread类,以及Runnable接口的方式实现多线程,还可以通过Callable,Future创建,详见下面的代码示例
第一种方式 使用Callable、Future
import java.util.concurrent.*;
public class Test {
public static void main(String[] args) {
ExecutorService executorService = Executors.newCachedThreadPool();
Task task = new Task();
Future<Integer> future = executorService.submit(task);
executorService.shutdown();
System.out.println("主线程在执行任务...");
try {
Thread.sleep(2000);
} catch(InterruptedException ex) {
ex.printStackTrace();
}
try {
System.out.println("task运行结果:"+future.get());
} catch (InterruptedException ex) {
ex.printStackTrace();
} catch (ExecutionException ex) {
ex.printStackTrace();
}
System.out.println("所有任务执行完毕");
}
}
class Task implements Callable<Integer>{
@Override
public Integer call() throws Exception {
System.out.println("子线程在执行任务...");
//模拟任务耗时
Thread.sleep(5000);
return 1000;
}
}
执行结果:
子线程在执行任务...
主线程在执行任务...
task运行结果:1000
所有任务执行完毕
第二种方式 使用Callable、FutureTask
import java.util.concurrent.*;
public class Test {
public static void main(String[] args) {
ExecutorService executorService = Executors.newCachedThreadPool();
Task task = new Task();
FutureTask<Integer> futureTask = new FutureTask<Integer>(task);
executorService.submit(futureTask);
executorService.shutdown();
System.out.println("主线程在执行任务...");
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {
ex.printStackTrace();
}
try {
System.out.println("task运行结果:"+futureTask.get());
} catch (InterruptedException ex) {
ex.printStackTrace();
} catch (ExecutionException ex) {
ex.printStackTrace();
}
System.out.println("所有任务执行完毕");
}
}
class Task implements Callable<Integer>{
@Override
public Integer call() throws Exception {
System.out.println("子线程在执行任务...");
//模拟任务耗时
Thread.sleep(5000);
return 1000;
}
}
执行结果:
子线程在执行任务...
主线程在执行任务...
task运行结果:1000
所有任务执行完毕