1.org中jackson转换json,springboot中内置jackson

ObjectMapper o=new ObjectMapper();List<>list=new ArrayList();String jons=o.writeAsValueString(list);

一、Fastion

使用阿里的fastjson

<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.83</version>
</dependency>import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

1.json格式的字符串 转JSONObject

public static void myJson(String str) {JSONObject obj = JSON.parseObject(str);// 测试结果System.out.println(obj);
}

2.json格式的字符串 转JSONArray

public static void myJson(String str) {        JSONArray array = JSON.parseArray(str);// 测试结果for(Object object : array){JSONObject obj = (JSONObject)object;System.out.println(obj);}
}

3.json格式的字符串 转JSONObject、JSONArray

public static void myJson(String str) {JSONObject jsonObj = JSON.parseObject(str);JSONArray array = JSON.parseArray(jsonObj.getString("name"));// 测试结果for(Object object:array){JSONObject obj = (JSONObject)object;System.out.println(obj);}
}

4.json格式的字符串 转实体类（javaBean）

public class Persion {private String name;private int age;public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}public static void myJson(String str) {
//如果str 是OBJECT 则：
String s = JSONObject.toJSONString(Persion);//再改对象Persion persion = JSON.parseObject(str, new TypeReference<Persion>(){});// 测试结果System.out.println("name:" + persion.getName() + " , " + "age:" + persion.getAge());
}

5.map格式 转JSONObject

public static void myJson(String str) {Map<String, Object> map = new HashMap<String, Object>();map.put("name","张三");map.put("age","18");JSONObject jsonObj=new JSONObject(map);// 测试结果System.out.println(jsonObj.toString());
}

6.实体类 转json格式的字符串

public static void myJson(Student student) {String str = JSONObject.toJSONString(student);// 测试结果System.out.println(str);
}

7、实体类转实体类

public static void myJson(Student1 student1) {String str = JSONObject.toJSONString(student);Student2 student2 = JSON.parseObject(str, new TypeReference<Student2>(){});
}

一、提取JsonObject（或Map）中的key-value值

1、获取JsonObject 的key

public void myJson(JSONObject params){Map<String, Object> map = params;Set<String> keys = map.keySet();for (String key : keys) {System.out.println(key+"-----"+map.get(key));}
}

2.获取JsonObject中的School的key-value值

public void myJson(JSONObject params){Map<String, Object> map = params;// {"小学":"4","初中":"2","高中":"1"}Map<String, String> m1 = (Map<String, String>) map.get("school");Set<String> keys = m1.keySet();for (String key : keys) {System.out.println(key+" ----- "+m1.get(key));}
}

二、Gosn

# 需要转jsonStirng的对象

Gson gson= new GsonBuilder().serializeNulls().create();
String jsonObject = gson.toJson(object);

三、String字符串分隔

解决字符串逗号分隔

String namesStr = "山东省,江苏省,广东省,浙江省";
String[] names = namesStr.split(",");
for (int i = 0, len = names.length; i < len; i++) {System.out.println(names[i])
}

2.alibaba中fastjson转换成json

 @GetMapping("/test")public TbUser testHttpClient(){String url="http://localhost:8080/saveUser";TbUser user = new TbUser();user.setPhone("13568775074");user.setUsername("minming");user.setPassword("123456");//fastjson的JSONObject将Object转jsonString s = JSONObject.toJSONString(user);//返回json类型数据String result = CloseableHttpCilentsUtils.doPost(url, user, null);fastjson的JSONObject将json转ObjectJSONObject  response = JSONObject.parseObject(result);TbUser parse = JSONObject.toJavaObject(response, TbUser.class);return parse;
}

返回结果：

{"password": "123456","phone": "13568775074","username": "minming"