JAVA中對list map根據map某個key值進行排序

標籤：array   排序   compareto   stat   一個   tostring   span   log   string   

 

 

package test; import java.util.ArrayList; import java.util.Collections;import java.util.Comparator;import java.util.HashMap;import java.util.List;import java.util.Map; public class java_ListMapSort {    public static void main(String[] args) {        // TODO Auto-generated method stub         List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();        Map<String, Object> map1 = new HashMap<String, Object>();        map1.put("name", "p");        map1.put("age", "5");        Map<String, Object> map2 = new HashMap<String, Object>();        map2.put("name", "h");        map2.put("age", "12");        Map<String, Object> map3 = new HashMap<String, Object>();        map3.put("name", "f");        map3.put("age", "31");        list.add(map1);        list.add(map3);        list.add(map2);        //排序前         for (Map<String, Object> map : list) {            System.out.println(map.get("age"));        }        Collections.sort(list, new Comparator<Map<String, Object>>() {            public int compare(Map<String, Object> o1, Map<String, Object> o2) {                Integer age1= Integer.valueOf(o1.get("age").toString()) ;//age1是從你list裡面拿出來的第一個 age                Integer age2= Integer.valueOf(o2.get("age").toString()) ; //age1是從你list裡面拿出來的第二個age                return age1.compareTo(age2);   //return age2.compareTo(age1);為降序            }        });        //排序後         System.out.println("-------------------");        for (Map<String, Object> map : list) {            System.out.println(map.get("age"));        }    }}

 

JAVA中對list map根據map某個key值進行排序