fastjson值java对象与JSON串互转

fastjson值java对象与JSON串互转

com.alibaba.fastjson.JSONObject时经常会用到它的转换方法，包括Java对象转成JSON串、JSON对象，JSON串转成java对象、JSON对象，JSON对象转换Java对象、JSON串等，使用方法总结如下，持续更新…
1、Java对象–>JSON对象
(JSON(Java对象实例)

 1 public class JSON2JavaTest{2     public static void main(String[] args) {3         Student stu = new Student("公众号BiggerBoy", "m", 2);4 5         //Java对象转化为JSON对象6         JSONObject jsonObject = (JSONObject) JSON(stu);7         System.out.println("Java对象转化为JSON对象n" + jsonObject);//{"name":"公众号编程大道","age":2,"sex":"m"}8         9     }
10 }

2、Java对象–>JSON字符串
JSONString(Java对象实例)

1 public class JSON2JavaTest{
2     public static void main(String[] args) {
3         Student stu = new Student("公众号BiggerBoy", "m", 2);
4 
5         //Java对象转换成JSON字符串 或者JSONString(stu); JSONObject继承了JSON
6         String stuString = JSONString(stu);
7         System.out.println("Java对象转换成JSON字符串n" + stuString);//{"age":2,"name":"公众号编程大道","sex":"m"}
8     }
9 }

3、JSON对象–>JSON字符串
JSONString();

 1 public class JSON2JavaTest{2     public static void main(String[] args) {3         Student stu = new Student("公众号BiggerBoy", "m", 2);4 5         //先转成JSON对象6         JSONObject jsonObject = (JSONObject) JSON(stu);7 8         //JSON对象转换为JSON字符串9         String jsonString = JSONString();
10         System.out.println("JSON对象转换为JSON字符串n" + jsonString);//{"name":"公众号编程大道","age":2,"sex":"m"}
11 
12     }
13 }

4、JSON对象–>Java对象
JavaObject(JSON对象实例, Java对象.class);

public class JSON2JavaTest{public static void main(String[] args) {Student stu = new Student("公众号BiggerBoy", "m", 2);//先转成JSON对象JSONObject jsonObject = (JSONObject) JSON(stu);//JSON对象转换成Java对象Student student = JavaObject(jsonObject, Student.class);System.out.println("JSON对象转换成Java对象n" + student);//Student{name='公众号编程大道', sex='m', age=2}}
}

5、JSON字符串–>JSON对象
JSONObject.parseObject(JSON字符串)

 1 public class JSON2JavaTest{2     public static void main(String[] args) {3         String stuString = "{"age":2,"name":"公众号 BiggerBoy","sex":"m"}";4 5         //JSON字符串转换成JSON对象6         JSONObject jsonObject1 = JSONObject.parseObject(stuString);7         System.out.println("JSON字符串转换成JSON对象n" + jsonObject1);//{"sex":"m","name":"公众号编程大道","age":2}8     }9 }

6、JSON字符串–>Java对象
JSONObject.parseObject(JSON字符串, Java对象.class);

1 public class JSON2JavaTest{
2     public static void main(String[] args) {
3         String stuString = "{"age":2,"name":"公众号 BiggerBoy","sex":"m"}";
4 
5         //JSON字符串转换成Java对象
6         Student student1 = JSONObject.parseObject(stuString, Student.class);
7         System.out.println("JSON字符串转换成Java对象n" + student1);//Student{name='公众号编程大道', sex='m', age=2}
8     }
9 }

如果student对象内有一个对象集合hobbies，相应的，JSON字符串转Map时如果不做处理，hobbies内的字段顺序可能会和原始hobbies字段值不一样

如下，第一次打印hobbies中的hobbyType跑到hobbyName前了，而原始JSON串中恰好和这相反，对于接口加解密生成签名时，字符串顺序尤为重要，若要保证原始顺序，可以加一个参数Feature.OrderedField

第二次打印的hobbies字段内的字符串顺序和原始字符串中一致。

String str1 = "{"age":2,"hobbies":[{"hobbyName":"篮球","hobbyType":1},{"hobbyName":"跳绳","hobbyType":2}],"name":"公众号BiggerBoy","sex":"m"}";Map map = JSONObject.parseObject(str1, Map.class);
System.out.JSONString(map));
//{"hobbies":[{"hobbyType":1,"hobbyName":"篮球"},{"hobbyType":2,"hobbyName":"跳绳"}],"sex":"m","name":"公众号BiggerBoy","age":2}Map map1 = JSONObject.parseObject(str1, Map.class, Feature.OrderedField);
System.out.JSONString(map1));
//{"hobbies":[{"hobbyName":"篮球","hobbyType":1},{"hobbyName":"跳绳","hobbyType":2}],"sex":"m","name":"公众号BiggerBoy","age":2}

7、JSON字符串–>List<Java对象>
List parseArray(JSON字符串, Java对象.class)

public class JSON2JavaTest{public static void main(String[] args) {String stuString = "[{"age":2,"name":"公众号","sex":"m"},{"age":18,"name":"BiggerBoy","sex":"m"}]";//JSON字符串转换成Java对象List<Student> studentList = JSONObject.parseArray(stuString, Student.class);System.out.println("JSON字符串转换成Java对象listn" +studentList );}
}