方法描述：

1、Callable最重要的兩個優點：可以獲取返回值、丟擲異常

2、執行緒實現

2.1、定義執行緒實現Callable方法，並設定返回的資料型別，如：Callable<List<Map<String, Object>>>

2.2、可實現多個構造方法，提供其他方法呼叫，如：

public MyThread2(CountDownLatch countDownLatch){...    }
public MyThread2(String type, String username) {....    }
public MyThread2(CountDownLatch countDownLatch,
 
 String type, String username) {...   }

2.3、重寫call方法，可以再該方法中直接返回資料，可丟擲異常.

 public List<Map<String, Object>> call() throws Exception { 
		//doing something
	return list;
   }

2.3、呼叫執行緒

2.3.1、例項化ExecutorService物件、定義future物件接受結果

2.3.2、ExecutorService物件呼叫執行緒

2.3.3、future物件阻塞等待資料

// 這個執行緒池可以根據需要例項化不同的執行緒池
 

ExecutorService exec = Executors.newCachedThreadPool();
  
List<Future<List<Map<String, Object>>>> results = new ArrayList<>();//Future 相當於是用來存放Executor執行的結果的一種容器


String[] threadNames = new String[]{"other", "tgbms_dy", "sxxm", "htsq", "newOa", "ECN", "common", "BhtXtpt"
 
, "JdgcjXtp", "WddXtpt", "XjbXtp"};
for (String item : threadNames) {
            System.out.println("執行執行緒：" + item);
            results.add(exec.submit(new MyThread2(item, username)));
}


for (Future<List<Map<String, Object>>> fs : results) {
            //阻塞阻塞等待
            List<Map<String, Object>> list = fs.get();
            
            if (list.size() > 0) {
                for (int i = 0; i < list.size(); i++) {
                    HashMap<String, Object> map = new HashMap<>();
                    map.put("system", list.get(i).get("system"));
                    map.put("todoTaskCount", list.get(i).get("todoTaskCount"));
                    map.put("systemName", list.get(i).get("systemName"));

                    data.add(map);
                }
            }
        }
        exec.shutdown();

具體實現方式：

呼叫主方法類

/**
*多執行緒獲取待辦資料
*
* @param username
* @return
*/
public static void main(String[] args) throws Exception {
   String username = "li_xibang";
   List<Map<String, Object>> data = new ArrayList<>();

   long time = System.currentTimeMillis();

   // 這個執行緒池可以根據需要例項化不同的執行緒池
   ExecutorService exec = Executors.newCachedThreadPool();

   List<Future<List<Map<String, Object>>>> results = new ArrayList<>();//Future 相當於是用來存放Executor執行的結果的一種容器

   String[] threadNames = new String[]{"other", "tgbms_dy", "sxxm", "htsq", "newOa", "ECN", "common", "BhtXtpt", "JdgcjXtp", "WddXtpt", "XjbXtp"};
   //通過標記迴圈調多執行緒
   for (String item : threadNames) {
       System.out.println("執行執行緒：" + item);
       results.add(exec.submit(new MyThread2(item, username)));
   }

   for (Future<List<Map<String, Object>>> fs : results) {
       //阻塞阻塞等待（再次回一致等待資料的返回）
       List<Map<String, Object>> list = fs.get();
       HashMap<String, Object> map = new HashMap<>();

       map.put("system", list.get(0).get("system"));
       map.put("todoTaskCount", list.get(0).get("todoTaskCount"));
       map.put("systemName", list.get(0).get("systemName"));

       data.add(map);

       System.out.println("還未完成");
   }
   exec.shutdown();

   long time2 = System.currentTimeMillis();
   System.out.println("所花費時間:" + (time2 - time));

   System.out.println(Thread.currentThread().getName() + "結束");

}

執行緒實現類

package com.sanxia.gaoke.thread;

import com.sanxia.gaoke.service.impl.TodoServiceImpl;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;

/**
 * Created by Administrator on 2018/6/5.
 */
public class MyThread2 implements Callable<List<Map<String, Object>>> {

    private String taskType;
    private String username;
    private CountDownLatch countDownLatch;

    public MyThread2(CountDownLatch countDownLatch){
        this.countDownLatch = countDownLatch;
    }

    public MyThread2(String type, String username) {
        this.taskType = type;
        this.username = username;
    }

    public MyThread2(CountDownLatch countDownLatch, String type, String username) {
        this.countDownLatch = countDownLatch;
        this.taskType = type;
        this.username = username;
    }

    @Override
    public List<Map<String, Object>> call() throws Exception {
        List<Map<String, Object>> list = new ArrayList<>();
        try {
            if (taskType.equals("other")) {
                //其它待辦數
                list = new TodoServiceImpl().getOtherNum(list, username);
            } else if (taskType.equals("tgbms_dy")) {
                //xx待辦數
                list = new TodoServiceImpl().getTgbmsNum(list, username);
            } else if (taskType.equals("sxxm")) {
                //xx系統待辦數
                list = new TodoServiceImpl().getSxxmNum(list, username);
            } else if (taskType.equals("htsq")) {
                //xx系統待辦數獲取
                list = new TodoServiceImpl().getQdpNum(list, username);
            } else if (taskType.equals("newOa")) {
                //新OA系統待辦數
                list = new TodoServiceImpl().getNewOaNum(list, username);
            } else if (taskType.equals("ECN")) {
                //ECN待辦數
                list = new TodoServiceImpl().getEcnNum(list, username);
            } else if (taskType.equals("common")) {
                //xx系統待辦數
                list = new TodoServiceImpl().getOaWithNum(list, username);
            } else {
                System.out.println("引數taskType為空，請確認...");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return list;
    }
}