[JAVA] JSON 변환 (String, Map, List, JSONString, JSONObject, JSONArray)

JSON 변환

pom.xml

라이브러리는 json-sample, jackson-databind를 사용하였습니다.

<!-- https://mvnrepository.com/artifact/com.googlecode.json-simple/json-simple -->
<dependency>
	<groupId>com.googlecode.json-simple</groupId>
	<artifactId>json-simple</artifactId>
	<version>1.1.1</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
	<groupId>com.fasterxml.jackson.core</groupId>
	<artifactId>jackson-databind</artifactId>
	<version>2.12.3</version>
</dependency>

 

JsonUtils.java

1. Map을 JSONString으로 변환

2. List<Map>을 JSONString으로 변환

3. String을 JSONObject를 변환

4. JSONObject를 Map<String, String>으로 변환

5. JSONArray를 List<Map<String, String>>으로 변환

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * JSON 관련된 유틸리티 클래스
 */
public class JsonUtils { 

	/**
	 * Map을 JSONString으로 변환
	 * 
	 * @param map
	 * @return String
	 */
	@SuppressWarnings("unchecked")
	public static String getJsonStringFromMap(Map<String, Object> map) {

		JSONObject json = new JSONObject();

		for (Map.Entry<String, Object> entry : map.entrySet()) {
			json.put(entry.getKey(), entry.getValue());
		}

		return json.toJSONString();
	}

	/**
	 * List<Map>을 JSONString으로 변환
	 * 
	 * @param list
	 * @return String
	 */
	@SuppressWarnings("unchecked")
	public static String getJsonStringFromList(List<Map<String, Object>> list) {

		JSONArray jsonArray = new JSONArray();

		for (Map<String, Object> map : list) {
			jsonArray.add(getJsonStringFromMap(map));
		}

		return jsonArray.toJSONString();
	}
	
	/**
	 * String을 JSONObject를 변환
	 * 
	 * @param jsonStr
	 * @return jsonObject
	 */
	public static JSONObject getJsonObjectFromString(String jsonStr) { 
	
		JSONObject jsonObject = new JSONObject();
		
		JSONParser jsonParser = new JSONParser();
		
		try {
			
			jsonObject = (JSONObject) jsonParser.parse(jsonStr);
			
		} catch (ParseException e) {
			e.printStackTrace();
		}
		
		return jsonObject;
	}
	
	/**
	 * JSONObject를 Map<String, String>으로 변환
	 * 
	 * @param jsonObject
	 * @return map
	 */
	@SuppressWarnings("unchecked")
	public static Map<String, Object> getMapFromJsonObject(JSONObject jsonObject) { 

		Map<String, Object> map = null;
		
		try {

			map = new ObjectMapper().readValue(jsonObject.toJSONString(), Map.class);

		} catch (JsonParseException e) {
			e.printStackTrace();
		} catch (JsonMappingException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		return map;
	}
	
	/**
	 * JSONArray를 List<Map<String, String>>으로 변환
	 * 
	 * @param jsonArray
	 * @return list
	 */
	public static List<Map<String, Object>> getListMapFromJsonArray(JSONArray jsonArray) {

		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();

		if (jsonArray != null) {

			int jsonSize = jsonArray.size();

			for (int i = 0; i < jsonSize; i++) {

				Map<String, Object> map = getMapFromJsonObject((JSONObject)jsonArray.get(i));
				list.add(map);
			}
		}

		return list;
	}
}

 

JsonUtilsTest.java

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.junit.Before;
import org.junit.Test;

public class JsonUtilsTest {
	
	Map<String, Object> map = null;	
	List<Map<String, Object>> list = null;
	
	String jsonStr = "{\"key01\":\"value01\",\"key02\":\"value02\",\"key03\":\"value03\",\"key04\":\"value04\",\"key05\":\"value05\"}";
	
	JSONObject jsonObject = null;	
	JSONArray jsonArray = null;
	
	@Before
	public void initJsonStringParam() {
		
		map = new HashMap<String, Object>();
		map.put("key01", "value01");
		map.put("key02", "value02");
		map.put("key03", "value03");
		map.put("key04", "value04");
		map.put("key05", "value05");
		
		list = new ArrayList<Map<String, Object>>(); 
		list.add(map);		
		list.add(map);		
		list.add(map);
	}
	
	@SuppressWarnings("unchecked")
	@Before
	public void initJsonObjectParam() {
		
		jsonObject = new JSONObject();
		jsonObject.put("key01", "value01");
		jsonObject.put("key02", "value02");
		jsonObject.put("key03", "value03");
		jsonObject.put("key04", "value04");
		jsonObject.put("key05", "value05");
		
		jsonArray = new JSONArray();
		jsonArray.add(jsonObject);
		jsonArray.add(jsonObject);
		jsonArray.add(jsonObject);
	}

	@Test
	public void testGetJsonStringFromMap() {
		
		String jsonStr = JsonUtils.getJsonStringFromMap(map);
			
		System.out.println("JsonStringFromMap : " + jsonStr);
	}

	@Test
	public void testGetJsonStringFromList() {

		String jsonStr = JsonUtils.getJsonStringFromList(list);
		
		System.out.println("JsonStringFromList : " + jsonStr);
	}
	
	
	@Test
	public void testGetJsonObjectFromString() {
		
		JSONObject jsonObject = JsonUtils.getJsonObjectFromString(jsonStr);
		
		System.out.println("JsonObjectFromString : " + jsonObject);
	}
	
	
	@Test
	public void testGetMapFromJsonObject() {
	
		Map<String, Object> map = JsonUtils.getMapFromJsonObject(jsonObject);
		
		System.out.println("MapFromJsonObject : " + map);
	}
	
	@Test
	public void testGetListMapFromJsonArray() {
	
		List<Map<String, Object>> list = JsonUtils.getListMapFromJsonArray(jsonArray);
		
		System.out.println("ListMapFromJsonArray : " + list);
	}
}

 

JSON library json-simple 사용법 - https://tychejin.tistory.com/139
JSON library Gson 사용법 - https://tychejin.tistory.com/136
JSON library Jackson 사용법 - https://tychejin.tistory.com/134