java比较json对象的中的值

给你一个demo参考下，实现的逻辑是先把json转换为list，然后list进行排序。代码如下

package com;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import com.alibaba.fastjson.JSON;

public class TestSort {
    public static void main(String[] args) {
        String json = 
                "[ { \"key\": \"a\", \"value\": 5 }," 
                + "{ \"key\": \"b\", \"value\": 3 },"
                + "{ \"key\": \"c\", \"value\": 7 }]";
        List<MyObject> list =  JSON.parseArray(json,MyObject.class); 
        Collections.sort(list, new Comparator<MyObject>() {
            @Override
            public int compare(MyObject u1, MyObject u2) {
                int diff = u1.getValue() - u2.getValue();
                if (diff > 0) {
                    return 1;
                } else if (diff < 0) {
                    return -1;
                }
                return 0;
            }
        });
        // max
        System.out.println("min key="+list.get(0).getKey()+", value="+list.get(0).getValue());
        System.out.println("max key="+list.get(list.size()-1).getKey()+", value="+list.get(list.size()-1).getValue());
    }
}

输出结果如下

min key=b, value=3
max key=c, value=7

辅助工具类

package com;

import java.io.Serializable;

public class MyObject implements Serializable {
    private String key;
    private Integer value;

    public String getKey() {
        return key;
    }
    public void setKey(String key) {
        this.key = key;
    }
    public Integer getValue() {
        return value;
    }
    public void setValue(Integer value) {
        this.value = value;
    }
}

集合->对象（属性：key，value），遍历集合获取max的key和min的key。

public static void main(String[] args) {
        Map<String, Object> map = new HashMap<>();
        map.put("key","a");
        map.put("value",5);
        Map<String, Object> map1 = new HashMap<>();
        map1.put("key","b");
        map1.put("value",3);
        Map<String, Object> map2 = new HashMap<>();
        map2.put("key","c");
        map2.put("value",7);
        List<Map<String, Object>> maps = new ArrayList<>();
        maps.add(map);
        maps.add(map1);
        maps.add(map2);
        Collections.sort(maps, new Comparator<Map<String, Object>>() {
            @Override
            public int compare(Map<String, Object> o1, Map<String, Object> o2) {
                Integer key1 = Integer.valueOf(o1.get("value").toString());
                Integer key2 = Integer.valueOf(o2.get("value").toString());
                return key1.compareTo(key2);
            }
        });
        System.out.println("MIN==="+maps.get(0));
        System.out.println("MAX==="+maps.get(maps.size()-1));
    }

问题解决请采纳。

首先转成list对象，然后根据value直接排序就行了，如何排序，搜“java list 排序”一大堆

public static void json(){
        String str = "[{key:'a',value:5},{key:'b',value:2},{key:'c',value:3},{key:'d',value:1}]" ;  // 一个未转化的字符串
        JSONArray json = JSONArray.fromObject(str); // 首先把json字符串转成JSONArray对象
        ArrayList<String> list = new ArrayList();
        String [][] arr = new String[json.size()][2];
        if(json.size()>0){
            for(int i=0;i<json.size();i++){
                JSONObject job = json.getJSONObject(i);  // 遍历 jsonarray 数组，把每一个对象转成 json 对象
                arr[i][0] = job.get("key").toString();
                arr[i][1] = job.get("value").toString();
            }
        }
        sort(arr);
        System.out.println("min:" + arr[0][0]);
        System.out.println("max:" + arr[arr.length-1][0]);
    }
    public static void sort(String[][] list){
        for(int i=0;i<list.length;i++){
            for(int j=0;j<list.length-i-1;j++){
                if(Integer.parseInt(list[j+1][1]) < Integer.parseInt(list[j][1])){
                    String[] temp = list[j];
                    list[j] = list[j+1];
                    list[j+1] = temp;
                }
            }
        }
    }