json之com.google.gson.Gson

本文主要是介绍json之com.google.gson.Gson，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

需要导入：gson-2.2.4.jar

一、JSON与数组互转：

//将数组转JSON
int[] number = {1,2,3,4,5};
Gson gson = new Gson();  
String numberjson = gson.toJson(number);

//将JSON转数组
int[] numberNew = gson.fromJson(numberjson, int[].class); 

二、 JSON与JavaBean互转：

// JavaBean转JSON
Student stu = new Student("1001", "lwc");
Gson gson = new Gson();
String jsondata = gson.toJson(stu);

// JSON转JavaBean
stu = gson.fromJson(jsondata, Student.class); 

三、 JSON与List互转：

// List转JSON
List list = new ArrayList();
for (int i = 0; i < 5; i++) {list.add("element" + i);
}
Gson gson = new Gson();
String json = gson.toJson(list);

// JSON转List
List list2 = (List) gson.fromJson(json, Object.class); 

四、 JSON与泛型List互转：

// 泛型Lis转JSON
List<Student> list = new ArrayList<Student>();
for (int i = 0; i < 3; i++) {
Student stu = new Student("100" + i, "name" + i);list.add(stu);
}
Type type = newTypeToken<List<Student>>() {}.getType();
Gson gson = new Gson();
String json = gson.toJson(list, type);

//JSON转泛型Lis
List<Student> users = gson.fromJson(json.toString(), type);

五、Map转json：

// Map转JSON
Map map = new HashMap();
map.put("no", "1001");
map.put("name", "lwc");
Gson gson = new Gson();
String json = gson.toJson(map);

六、JSON与泛型Map互转：

// JSON转泛型Map
Map<String, Student> map = new HashMap<String, Student>();
for (int i = 0; i < 2; i++) {Student stu = new Student("100" + i, "name" + i);map.put("100" + i, stu);
}
Type type = new TypeToken<Map<String, Student>>() {}.getType();
Gson gson = new Gson();
String json = gson.toJson(map, type);

// 转泛型Map转JSON
Map<String, Student> mapStu = gson.fromJson(json.toString(), type);  

七、 JSON与带日期JavaBean互转：

/*** 日期序列化实用工具类*/
class DateDeserializerUtils implements  JsonDeserializer<java.util.Date> {public Date deserialize(JsonElement arg0, Type arg1,
JsonDeserializationContext arg2) throws JsonParseException {return new java.util.Date(arg0.getAsJsonPrimitive().getAsLong());}
}

/*** 日期解序列实用工具类*/
class DateSerializerUtils implements JsonSerializer<java.util.Date> {public JsonElement serialize(Date arg0, Type arg1,
JsonSerializationContext arg2) {return new JsonPrimitive(arg0.getTime());}
} 

public class Test {public static void main(String[] args) {// 带日期JavaBean转JSONStudent stu = new Student("1001", "lwc", new Date());Gson gson = new Gson();
gson = new GsonBuilder().registerTypeAdapter(Date.class,
new DateSerializerUtils()).setDateFormat(DateFormat.LONG).create();String json = gson.toJson(stu);// JSON转带日期JavaBeangson = new GsonBuilder().registerTypeAdapter(Date.class,
new                         DateDeserializerUtils()).setDateFormat(DateFormat.LONG).create();Type type = new TypeToken<Student>() {}.getType();Student s = gson.fromJson(json, type);// 泛型日期List转JSONList<Student> list = new ArrayList<Student>();list.add(new Student("1001", "name1", new Date()));list.add(new Student("1002", "name2", new Date()));gson = new GsonBuilder().registerTypeAdapter(Date.class,
new DateSerializerUtils()).setDateFormat(DateFormat.LONG).create();Type type2 = new TypeToken<List<Student>>() {}.getType();json = gson.toJson(list, type2);// JSON转泛型日期Listgson = new GsonBuilder().registerTypeAdapter(Date.class,
new DateDeserializerUtils()).setDateFormat(DateFormat.LONG).create();List<Student> stus = gson.fromJson(json.toString(), type);}
} 

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