package threadtest;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

public class T1 {

    public static void main(String[] args) throws Exception {

        //定义返回值集合

        List<Future<Map<String, Object>>> resultList = new ArrayList();

        //创建一个线程池

        ExecutorService taskExecutor = Executors.newFixedThreadPool(3);

        //执行多线程

        for (int i = 0; i < 4; i++) {//【实际使用中，这里可以是批量数据的循环】

            //定义要传入线程中的参数

            HashMap<String, Object> param = new HashMap<String, Object>();

            param.put("index", i);

            //创建线程执行类对象

            MyCallable c = new MyCallable(param);

            //执行线程并获取执行结果

            Future<Map<String, Object>> f = taskExecutor.submit(c);

            //将执行结果存入集合

            resultList.add(f);

        }

        //关闭线程池

        taskExecutor.shutdown();

        //批量处理线程执行结果

        for (Future<Map<String,Object>> future : resultList) {

            if (future != null);

            //这个get方法会阻塞直到获取到线程的执行结果

            Map<String, Object> map = future.get();

            System.out.println(map);

        }

    }

}

//自定义线程处理类

class MyCallable implements Callable<Map<String,Object>> {

    private HashMap<String, Object> paramMap;

    public MyCallable(HashMap<String, Object> paramMap) {

        super();

        this.paramMap = paramMap;

    }

    //call方法的返回值可以是任意类型，和Callable<Map<String,Object>>一致即可

    @Override

    public Map<String, Object> call() throws Exception {

        //定义返回map

        HashMap<String, Object> rtnMap = new HashMap<String, Object>();

        //获取参数中的内容

        Integer index = (Integer) paramMap.get("index");

        //处理业务逻辑

        int sum = 0;

        for (int i = 0; i <= index; i++) {

            System.out.println("index:"+index +"--- "+i);

            sum += i;

        }

        //返回业务逻辑结果

        rtnMap.put("index", index);

        rtnMap.put("sum", sum);

        return rtnMap;

    }

}