10个班级，每个班级20名学生，在指定的时间内查询每个班级学生的集合。 

               package cn.com.ld.study.thread;                    import java.util.ArrayList;          import java.util.Collection;          import java.util.HashMap;          import java.util.List;          import java.util.Map;          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;          import java.util.concurrent.TimeUnit;                    public class FutureTest {              //缓存操作数据集              private static final Map<Integer, List<Student>> sutdenMap = new HashMap<Integer, List<Student>>();              //初始化操作数据              static {                  List<Student> stuList = null;                  Student stu;                  for (int i = 0; i < 10; i++) {                      stuList = new ArrayList<Student>();                      for (int j = 0; j < 2; j++) {                          stu = new Student(j, "zld_" + i + "." + j, i);                          stuList.add(stu);                      }                      sutdenMap.put(i, stuList);                  }              }                        public static class Student {                  private int id;                  private String name;                  private int classID;                            public Student(int id, String name, int classID) {                      this.id = id;                      this.name = name;                      this.classID = classID;                  }                            public String toString() {                      return Student.class.getName() + "(id:" + this.id + ",name:"                              + this.name + ")";                  }                        }                            /**                 * @filename: SearchTask                 * @description: 查询任务                * @author lida                * @date 2013-4-1 下午3:02:29                    */              public static class SearchTask implements Callable<List<Student>> {                            public final int classID;                  public long sleepTime;                            /**                     * <p>Title: </p>                     * <p>Description: </p>                     * @param classID  班级编号                  * @param sleepTime  模拟操作所用的时间数（毫秒）                  */                  SearchTask(int classID, long sleepTime) {                      this.classID = classID;                      this.sleepTime = sleepTime;                  }                            @Override                  public List<Student> call() throws Exception {                      //模拟操作所用的时间数（毫秒）                      Thread.sleep(sleepTime);                      List<Student> stuList = sutdenMap.get(classID);                      return stuList;                  }                        }                        public static void main(String[] args) {                  FutureTest ft = new FutureTest();                  ExecutorService exec = Executors.newCachedThreadPool();                  List<SearchTask> searchTasks = new ArrayList<SearchTask>();                  SearchTask st;                  for (int i = 0; i < 10; i++) {                      st = new SearchTask(i, 2001);//指定2001 毫米为最大执行时间                      searchTasks.add(st);                  }                            try {                      //要求认为在2000毫秒内返回结果，否则取消执行。                      List<Future<List<Student>>> futures = exec.invokeAll(searchTasks,                              2000, TimeUnit.MILLISECONDS);//invokeAll 第一个参数是任务列表；第二个参数是过期时间；第三个是过期时间单位                      for (Future<List<Student>> future : futures) {                          List<Student> students = future.get();                          for (Student student : students) {                              System.out.println(student.toString());                          }                      }                      exec.shutdown();                  } catch (InterruptedException e) {                      e.printStackTrace();                      Thread.interrupted();                  } catch (ExecutionException e) {                      e.printStackTrace();                  }              }          }          http://zld406504302.iteye.com/blog/1840091
package cn.com.ld.study.thread;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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;
import java.util.concurrent.TimeUnit;

public class FutureTest {
    //缓存操作数据集
    private static final Map<Integer, List<Student>> sutdenMap = new HashMap<Integer, List<Student>>();
    //初始化操作数据
    static {
        List<Student> stuList = null;
        Student stu;
        for (int i = 0; i < 10; i++) {
            stuList = new ArrayList<Student>();
            for (int j = 0; j < 2; j++) {
                stu = new Student(j, "zld_" + i + "." + j, i);
                stuList.add(stu);
            }
            sutdenMap.put(i, stuList);
        }
    }

    public static class Student {
        private int id;
        private String name;
        private int classID;

        public Student(int id, String name, int classID) {
            this.id = id;
            this.name = name;
            this.classID = classID;
        }

        public String toString() {
            return Student.class.getName() + "(id:" + this.id + ",name:"
                    + this.name + ")";
        }

    }

    /**
     * @filename: SearchTask
     * @description: 查询任务
     * @author lida
     * @date 2013-4-1 下午3:02:29
     */
    public static class SearchTask implements Callable<List<Student>> {

        public final int classID;
        public long sleepTime;

        /**
         * <p>Title: </p>
         * <p>Description: </p>
         * @param classID  班级编号
         * @param sleepTime  模拟操作所用的时间数（毫秒）
         */
        SearchTask(int classID, long sleepTime) {
            this.classID = classID;
            this.sleepTime = sleepTime;
        }

        @Override
        public List<Student> call() throws Exception {
            //模拟操作所用的时间数（毫秒）
            Thread.sleep(sleepTime);
            List<Student> stuList = sutdenMap.get(classID);
            return stuList;
        }

    }

    public static void main(String[] args) {
        FutureTest ft = new FutureTest();
        ExecutorService exec = Executors.newCachedThreadPool();
        List<SearchTask> searchTasks = new ArrayList<SearchTask>();
        SearchTask st;
        for (int i = 0; i < 10; i++) {
            st = new SearchTask(i, 2001);//指定2001 毫米为最大执行时间
            searchTasks.add(st);
        }

        try {
            //要求认为在2000毫秒内返回结果，否则取消执行。
            List<Future<List<Student>>> futures = exec.invokeAll(searchTasks,
                    2000, TimeUnit.MILLISECONDS);//invokeAll 第一个参数是任务列表；第二个参数是过期时间；第三个是过期时间单位
            for (Future<List<Student>> future : futures) {
                List<Student> students = future.get();
                for (Student student : students) {
                    System.out.println(student.toString());
                }
            }
            exec.shutdown();
        } catch (InterruptedException e) {
            e.printStackTrace();
            Thread.interrupted();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
}
http://zld406504302.iteye.com/blog/1840091