Java中解析json的四种方式

1）Gson
（1）添加依赖

<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.2.4</version>
</dependency>

（2）转化方法
① 对象转Json:

Gson gson = new Gson();
String json = gson.toJson(Object object);

② Json转对象

gson.fromJson(String json, Class<T> classOfT)

③.集合转Json

Gson gson = new Gson();
String json = gson.toJson(Object object);

④.Json转集合

TypeToken<T> typeOfT = new TypeToken<T>(){};
T fromJson = (T)gson.fromJson(json, typeOfT.getType());

2）Json-Lib
（1）添加依赖

<dependency>
<groupId>net.sf.json-lib</groupId>
<artifactId>json-lib</artifactId>
<version>2.4</version>
<classifier>jdk15</classifier>
</dependency>

（2）转化方法
① 对象转Json

JSONObject fromObject = JSONObject.fromObject(Object object);
String string = fromObject.toString();

② Json转对象

JSONObject fromObject2 = JSONObject.fromObject(string);
Object bean =JSONObject.toBean(JSONObject jsonObject, Class beanClass)

③ 集合转Json

JSONArray fromObject = JSONArray.fromObject(Object object);
String string = fromObject.toString();

④ Json转集合

JSONArray fromObject2 = JSONArray.fromObject(string);
Collection collection = JSONArray.toCollection
(JSONArray jsonArray, Class objectClass)

3）Fastjson
Fastjson是阿里巴巴公司开发的，Java语言编写的，JSON的处理器。

（1）添加依赖

<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.31</version>
</dependency>

（2）转化方法
① 对象转Json

JSON.toJSONString(Object object);

② Json转对象

JSON.parseObject(String text,Class<T> Class);

③ 集合转Json

JSON.toJSONString(Object object)

④ Json转集合:

JSON.parseArray(String text,Class<T> Class);

4）Jackson
（1）添加依赖

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.8</version>
</dependency>

（2）转换方法

public static String object_to_json(Object object) throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
return mapper.writeValueAsString(object);
}
public static <T> T json_to_object(String json, Class<T> mainClass, Class<?>... parametricClasses) throws JsonParseException, JsonMappingException, IOException {
ObjectMapper mapper = new ObjectMapper();
JavaType parametricType = mapper.getTypeFactory().constructParametricType(mainClass, parametricClasses);
T readValue = mapper.readValue(json, parametricType);
return readValue;
}