学习FastJson和Gson的用法

1.用FastJson，将JSON字符串转换为FastJson对象：

import com.alibaba.fastjson.JSONObject;  
String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";  
JSONObject jsonObject = JSONObject.parseObject(jsonString);

2.用FastJson，将JSON字符串转换为Java对象：

import com.alibaba.fastjson.JSONObject;  
String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";  
Person person = JSONObject.parseObject(jsonString, Person.class);

4.将JSON字符串转换为Java的集合对象：

import com.alibaba.fastjson.JSONArray;  
String jsonString = "[{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}, {\"name\":\"Mary\", \"age\":25, \"city\":\"Los Angeles\"}]";  
List<Person> personArray = JSONArray.parseArray(jsonString, Person.class);

5.将JSON字符串转换为Java的集合对象：

import com.alibaba.fastjson.JSON;  
List<Person> personList = new ArrayList<Person>();  
Person person1 = new Person();  
person1.setName("John");  
person1.setAge(30);  
person1.setCity("New York");  
Person person2 = new Person();  
person2.setName("Mary");  
person2.setAge(25);  
person2.setCity("Los Angeles");  
personList.add(person1);  
personList.add(person2);  
String jsonString = JSON.toJSONString(personList);

6.用Gson,添加Json对象：

Gson gson = new Gson();  
JsonObject jsonObject1 = new JsonObject();  
jsonObject1.addProperty("name", "John");  
jsonObject1.addProperty("age", 30);  
JsonObject jsonObject2 = new JsonObject();  
jsonObject2.addProperty("city", "New York");  
jsonObject2.addProperty("country", "USA");  
jsonObject1.add("location", jsonObject2); // 将jsonObject2作为一个新的属性添加到jsonO

7.用Gson,添加Json数组：

Gson gson = new Gson();  
JsonArray jsonArray = new JsonArray();  
jsonArray.add("Java");  
jsonArray.add("Python");  
jsonArray.add("C++");  
JsonObject jsonObject = new JsonObject();  
jsonObject.add("languages", jsonArray); // 将jsonArray作为一个新的属性添加到jsonObject中

8.用Gson,移除值：

son gson = new Gson();  
JsonObject jsonObject = new JsonObject();  
jsonObject.addProperty("name", "John");  
jsonObject.addProperty("age", 30);  
jsonObject.removeProperty("age"); // 移除age属性

9.用Gson,移除Json对象：

Gson gson = new Gson();  
JsonObject jsonObject1 = new JsonObject();  
jsonObject1.addProperty("name", "John");  
jsonObject1.addProperty("age", 30);  
JsonObject jsonObject2 = new JsonObject();  
jsonObject2.addProperty("city", "New York");  
jsonObject2.addProperty("country", "USA");  
jsonObject1.add("location", jsonObject2);  
jsonObject1.remove("location"); // 移除location属性，包括其包含的jsonObject2对象

10.用Gson，将JSON字符串转换为Gson对象:

Gson gson = new Gson();  
String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";  
JsonObject jsonObject = gson.fromJson(jsonString, JsonObject.class);

11.用Gson，json字符串转JAVA对象:

Gson gson = new Gson();  
String jsonString = "{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}";  
Person person = gson.fromJson(jsonString, Person.class);

12.用Gson，JSON字符串转换为Java的集合对象：

Gson gson = new Gson();  
String jsonString = "[{\"name\":\"John\", \"age\":30, \"city\":\"New York\"}, {\"name\":\"Mary\", \"age\":25, \"city\":\"Los Angeles\"}]";  
Person[] personArray = gson.fromJson(jsonString, Person[].class);  
List<Person> personList = gson.fromJson(jsonString, new TypeToken<List<Person>>() {}.getType());

13.用Gson,将Gson对象转换为JSON字符串：

Gson gson = new Gson();  
JsonObject jsonObject = new JsonObject();  
jsonObject.addProperty("name", "John");  
jsonObject.addProperty("age", 30);  
jsonObject.addProperty("city", "New York");  
String jsonString = gson.toJson(jsonObject);

14.用Gson,将Java对象转换为JSON字符串：

Gson gson = new Gson();  
Person person = new Person();  
person.setName("John");  
person.setAge(30);  
person.setCity("New York");  
String jsonString = gson.toJson(person);

15.用Gson,将Java的集合对象转换为JSON字符串：

Gson gson = new Gson();  
List<Person> personList = new ArrayList<Person>();  
Person person1 = new Person();  
person1.setName("John");  
person1.setAge(30);  
person1.setCity("New York");  
Person person2 = new Person();  
person2.setName("Mary");  
person2.setAge(25);  
person2.setCity("Los Angeles");  
personList.add(person1);  
personList.add(person2);  
String jsonString = gson.toJson(personList);