import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

 * ClassName: Sort

 * @Description: list集合按元素的某一属性排序

 * @author ljw

 * @date 2018年5月24日

 */

public class Sort {

    public static void main(String[] args) {

        List> list = new ArrayList<>();

        for (int i = 0; i < 10; i++) {

            Map map = new HashMap<>();

            Integer random = (int)(Math.random() * 100);

            map.put("random", random);

            list.add(map);

        }

        //排序前

        System.out.println("排序前：" + list);

        Collections.sort(list, new Comparator>() {

            public int compare(Map m1, Map m2) {

                //降序

                //return m2.get("random").compareTo(m1.get("random"));

                //升序

                return m1.get("random").compareTo(m2.get("random"));               

            }

        });

        //排序后

        System.out.println("排序后：" + list);

    }

}