方式一：json-lib
<dependency><groupId>net.sf.json-lib</groupId><artifactId>json-lib</artifactId><version>2.4</version><classifier>jdk15</classifier></dependency>
import java.util.HashMap;import java.util.Map;import net.sf.json.JSONObject;public class test{public static void main(String[] args) {Map map = new HashMap();map.put("test", "test1");JSONObject jsonObject = JSONObject.fromObject(map);System.out.println("输出的结果是：" + jsonObject);//3、将json对象转化为json字符串String result = jsonObject.toString();System.out.println(result);}}
json-lib是一个比较老的解决方案，近几年都没有升级过，它的适用环境是JDK1.5，使用JDK1.6就有可能会报错。所以配置上加入classifier-jdk15来解决这个问题。
方式二：alibaba
<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.41</version></dependency>
public static void main(String[] args) {Map<String, String> map = new HashMap<>();map.put("test", "test1");map.put("target", "from");String jsonString = JSONObject.toJSONString(map);System.out.println(jsonString);Map<String, String> map2 = JSONObject.parseObject(jsonString, Map.class);System.out.println(map2.get("test"));}
方式三：google--Gson
<!-- /artifact/com.google.code.gson/gson --><dependency><groupId>com.google.code.gson</groupId><artifactId>gson</artifactId><version>2.3.1</version></dependency>
public static void main(String[] args) {Map<String, String> map = new HashMap<>();map.put("test", "test1");map.put("target", "from");Gson gson = new Gson();String gsonStr = gson.toJson(map);System.out.println(gsonStr);Map map3 = gson.fromJson(gsonStr, Map.class);System.out.println(map3.get("target"));}
