java比较json对象的中的值

Question

[ { "key": "a", "value": 5 },
{ "key": "b", "value": 3 },
{ "key": "c", "value": 7 }]
就这种json ,怎么实现比较的是value中的int的值的大小, 而返回的是key比如例子中返回的是 "max" = "c", "min" = "b" ?

Answer 1

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;
    }
}