FutureTask 测试用例

package currentTest.BlockingQueue;

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

/**
 * 测试FutureTask的用法，如果不想分支线程阻塞主线程，又想取得分支线程的执行结果，就用FutureTask
 * 
 * @author zhailzh
 * 
 */
public class FutureTaskTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        CountNum cn = new CountNum(0);
        // FutureTask<Integer> 这里的表示返回的是Integer
        FutureTask<Integer> ft = new FutureTask<Integer>(cn);
        Thread td = new Thread(ft);
        System.out.println("futureTask执行计算:" + System.currentTimeMillis());
        td.start();
        System.out.println("main 主线程可以做些其他事情" + System.currentTimeMillis());
        try {
            // futureTask的get方法会阻塞，知道可以取得结果为止
            Integer result = ft.get();
            System.out.println("计算的结果是:" + result);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        System.out.println("取得分支线程执行的结果后，主线程可以继续处理其他事项");
    }

}

class CountNum implements Callable {
    private Integer sum;

    public CountNum(Integer sum) {
        this.sum = sum;
    }

    public Object call() throws Exception {
        for (int i = 0; i < 100; i++) {
            sum = sum + i;
        }
        // 休眠5秒钟，观察主线程行为，预期的结果是主线程会继续执行，到要取得FutureTask的结果是等待直至完成
        Thread.sleep(3000);
        System.out.println("futureTask 执行完成" + System.currentTimeMillis());
        return sum;
    }

}