Java中对jsonArray的排序,使用的是Gson

Posted 2021-01-02 努力做一个伪程序员

使用Gson对json解析字符串,转化为json对象.

先上代码: 下面是main方法里面的代码

package testJava;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import com.google.gson.JsonParser;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;

public class TestJava {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        jsoaArraySort();
    }
    public static void jsoaArraySort() {
        String arrayData = "["
                + "{"Name":"TVS","No":" + 202 + ","Length":" + 23 + "},"
                + "{"Name":"TVC","No":" + 203 + ","Length":" + 14 + "},"
                + "{"Name":"Wel","No":" + 345 + ","Length":" + 35 + "},"
                + "{"Name":"Sma","No":" + 678 + ","Length":" + 45 + "},"
                + "{"Name":"Sma","No":" + 136 + ","Length":" + 15 + "},"
                + "{"Name":"Cus","No":" + 257 + ","Length":" + 17 + "},"
                + "{"Name":"And","No":" + 678 + ","Length":" + 16 + "},"
                + "{"Name":"Roo","No":" + 136 + ","Length":" + 56 + "}"
                +"]";
        JsonParser parser = new JsonParser();
        JsonArray jsonArray = parser.parse(arrayData).getAsJsonArray();
        System.out.println("init jsonArray=" + jsonArray.toString());

        JsonArray sort_JsonArray = new JsonArray();
        List<JsonObject> list = new ArrayList<JsonObject>();
        JsonObject jsonObj = null;
        for (int i = 0; i < jsonArray.size(); i++) {
            jsonObj = (JsonObject) jsonArray.get(i);
            list.add(jsonObj);
        }
        //这里最核心的地方就是SortComparator这个类
        //其中构造方法的参数: 
        //sortItem是要排序的jsonArray中一个元素, 这里我选择是Name, 也可以选择No或者是Length
        //sortType是排序的类型, 有三种情况
            // 1. 排序的元素对应的值是int， 那么sortType = "int";
            // 2. 排序的元素对应的值是string， 那么sortType = "string";
            // 3. 排序的元素对应的是是其他类型, 默认是不排序, (后面可以扩展)
        //sortDire是排序的方向, 可以是asc或者desc, 默认是数据的原始方向(就是没有排序方向)
        String sortItem = "Length";
        String sortType = "int";
        String sortDire = "desc";
        Collections.sort(list, new SortComparator(sortItem, sortType, sortDire));
        for (int i = 0; i < list.size(); i++) {
            jsonObj = list.get(i);
            sort_JsonArray.add(jsonObj);
        }
        System.out.println("after sort_JsonArray=" + sort_JsonArray.toString());      
    }
}

下面给出SortComparator.java

package testJava;

import java.util.Comparator;
import com.google.gson.JsonObject;

public class SortComparator implements Comparator<JsonObject> {
    
    private String sortItem;
    private String sortType;
    private String sortDire;
    
    public SortComparator(String sortItem, String sortType, String sortDire) {
        this.sortItem = sortItem;
        this.sortType = sortType;
        this.sortDire = sortDire;
    }
    
    @Override
    public int compare(JsonObject o1, JsonObject o2) {
        String value1 = o1.getAsJsonObject().get(sortItem).getAsString();
        String value2 = o2.getAsJsonObject().get(sortItem).getAsString();
        if ("int".equalsIgnoreCase(this.sortType)) { // int sort
            int int1 = Integer.parseInt(value1);
            int int2 = Integer.parseInt(value2);
            if ("asc".equalsIgnoreCase(this.sortDire)) {
                return int1 - int2;
            } else if ("desc".equalsIgnoreCase(this.sortDire)) {
                return int2 - int1;
            } else {
                return 0;
            }      
        } else if ("string".equalsIgnoreCase(this.sortType)) { // string sort
            if ("asc".equalsIgnoreCase(this.sortDire)) {
                return value1.compareTo(value2);
            } else if ("desc".equalsIgnoreCase(this.sortDire)) {
                return value2.compareTo(value1);
            } else {
                return 0;
            }
        } else { // nothing sort
            return 0;
        }        
    }
}

测试的结果:

jsonArray的初始值如下:
jsonArray = [
　　{"Name":"TVS","No":202,"Length":23},
　　{"Name":"TVC","No":203,"Length":14},
　　{"Name":"Wel","No":345,"Length":35},
　　{"Name":"Sma","No":678,"Length":45},
　　{"Name":"Sma","No":136,"Length":15},
　　{"Name":"Cus","No":257,"Length":17},
　　{"Name":"And","No":678,"Length":16},
　　{"Name":"Roo","No":136,"Length":56}
];

下面是按照Name元素从小到达排序: SortComparator("Name", "string", "asc")
after sort_JsonArray=[
　　　{"Name":"And","No":678,"Length":16},
　　　{"Name":"Cus","No":257,"Length":17},
　　　{"Name":"Roo","No":136,"Length":56},
　　　{"Name":"Sma","No":678,"Length":45},
　　　{"Name":"Sma","No":136,"Length":15},
　　　{"Name":"TVC","No":203,"Length":14},
　　　{"Name":"TVS","No":202,"Length":23},
　　　{"Name":"Wel","No":345,"Length":35}
　]

下面是按照Name元素从大到小排序: SortComparator("Name", "string", "desc")
after sort_JsonArray=[
    {"Name":"Wel","No":345,"Length":35},
    {"Name":"TVS","No":202,"Length":23},
    {"Name":"TVC","No":203,"Length":14},
    {"Name":"Sma","No":678,"Length":45},
    {"Name":"Sma","No":136,"Length":15},
    {"Name":"Roo","No":136,"Length":56},
    {"Name":"Cus","No":257,"Length":17},
    {"Name":"And","No":678,"Length":16}
]

下面是按照Length元素从小到大排序: SortComparator("Length", "int", "asc")
after sort_JsonArray=[
    {"Name":"TVC","No":203,"Length":14},
    {"Name":"Sma","No":136,"Length":15},
    {"Name":"And","No":678,"Length":16},
    {"Name":"Cus","No":257,"Length":17},
    {"Name":"TVS","No":202,"Length":23},
    {"Name":"Wel","No":345,"Length":35},
    {"Name":"Sma","No":678,"Length":45},
    {"Name":"Roo","No":136,"Length":56}
]

下面是按照Length元素从大到小排序: SortComparator("Length", "int", "desc")
after sort_JsonArray=[
    {"Name":"Roo","No":136,"Length":56},
    {"Name":"Sma","No":678,"Length":45},
    {"Name":"Wel","No":345,"Length":35},
    {"Name":"TVS","No":202,"Length":23},
    {"Name":"Cus","No":257,"Length":17},
    {"Name":"And","No":678,"Length":16},
    {"Name":"Sma","No":136,"Length":15},
    {"Name":"TVC","No":203,"Length":14}
]