java - 使用 java 中的键对 Json 响应进行分组 - android studio

Question

我是java和android开发的新手。我正在学习json解析。我收到类似这样的 json 响应。

{"code":"0","data":    
[ {"chrDesigName":"Developer","chrempName":"Test Employee1"},
  {"chrDesigName":"Developer","chrempName":"Test Employee2"}, 
  {"chrDesigName":"Tester","chrempName":"Test Employee3"},
  {"chrDesigName":"Analyst","chrempName":"Test Employee4"},
  {"chrDesigName":"Developer","chrempName":"Test Employee5"},
  {"chrDesigName":"Tester","chrempName":"Test Employee6"}]

我想把这个 Json 解析成这样的东西。

{"Developer" : [{"chrempName" : "Test Employee1"},
                    {"chrempName" : "Test Employee2"},
                    {"chrempName" : "Test Employee5"}],
"Tester" : [{"chrempName" : "Test Employee3"},
                    {"chrempName" : "Test Employee6"}],
"Analyst" : [{"chrempName" : "Test Employee4"}]}  

我怎样才能实现这个目标？我的动机是根据所有员工的职责对他们进行分组。

Answer 1

作为一个快速技巧，我使用了 2 个不同的库来做到这一点。您也可以使用 jackson “统一”。

import java.io.StringWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.codehaus.jackson.map.ObjectMapper;

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

public class JsonReformatter {

    public static void main(String[] args) throws Exception {
        String jsonString = "{\"code\": \"0\",\"data\": [{\"chrDesigName\": \"Developer\",\"chrempName\": \"Test Employee1\"},{\"chrDesigName\": \"Developer\",\"chrempName\": \"Test Employee2\"},{\"chrDesigName\": \"Tester\",\"chrempName\": \"Test Employee3\"},{\"chrDesigName\": \"Analyst\",\"chrempName\": \"Test Employee4\"},{\"chrDesigName\": \"Developer\",\"chrempName\": \"Test Employee5\"},{\"chrDesigName\": \"Tester\",\"chrempName\": \"Test Employee6\"}]}";

        ObjectMapper mapper = new ObjectMapper();

        // Map<String, Object> dataMap = mapper.readValue(jsonString,
        // new TypeReference<Map<String, Object>>() {
        // });
        //
        // System.out.println(dataMap.get("data") +
        // ((ArrayList)dataMap.get("data")).get(0).getClass().getName()) ;

        JsonArray dataArray = new JsonParser().parse(jsonString).getAsJsonObject().getAsJsonArray("data");

        HashMap<String, List<String>> designationsMap = new HashMap<String, List<String>>();

        for (JsonElement element : dataArray) {
            String designation = element.getAsJsonObject().get("chrDesigName").getAsString();
            String empName = element.getAsJsonObject().get("chrempName").getAsString();
            if (designationsMap.containsKey(designation)) {
                designationsMap.get(designation).add(empName);
            } else {
                ArrayList<String> emptyList = new ArrayList<String>();
                emptyList.add(empName);
                designationsMap.put(designation, emptyList);
            }
        }

        StringWriter result = new StringWriter();
        mapper.writeValue(result, designationsMap);
        System.out.println(result);

    }

}

这会打印

{"分析师":["测试员工4"],"测试员":["测试员工3","测试 员工6"],"开发人员":["测试员工1","测试员工2","测试员工5"]}

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.8.1</version>
</dependency>

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.7</version>
</dependency>