JAVA对象与JSON转换的各种方法-fastjson

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fastjson maven

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.62</version>
</dependency>

1、Java对象–>JSON对象

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        User user = new User("张三", "男", 18);
 
        //Java对象转化为JSON对象
        JSONObject jsonObject = (JSONObject) JSONObject.toJSON(user);
        System.out.println("Java对象转化为JSON对象\n" + jsonObject);//{"name":"张三","age":18,"sex":"男"}
        
    }
}

2、Java对象–>JSON字符串

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        USer user = new User("张三", "男", 18);
 
        //Java对象转换成JSON字符串
        String userStr = JSONObject.toJSONString(user);
        System.out.println("Java对象转换成JSON字符串\n" + userStr);//{"age":18,"name":"张三","sex":"男"}
    }
}

3、JSON对象–>JSON字符串

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        User user = new User("张三", "男", 18);
 
        //先转成JSON对象
        JSONObject jsonObject = (JSONObject) JSONObject.toJSON(user);
 
        //JSON对象转换为JSON字符串
        String jsonString = jsonObject.toJSONString();
        System.out.println("JSON对象转换为JSON字符串\n" + jsonString);//{"name":"张三","age":18,"sex":"男"}
 
    }
}

4、JSON对象–>Java对象

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        User user1 = new User("张三", "男", 18);
 
        //先转成JSON对象
        JSONObject jsonObject = (JSONObject) JSONObject.toJSON(user1);
        
        //JSON对象转换成Java对象
        User user = JSONObject.toJavaObject(jsonObject, User.class);
        System.out.println("JSON对象转换成Java对象\n" + user);//User{name='张三', sex='男', age=18}
    }
}

5、JSON字符串–>JSON对象

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        String userStr = "{\"age\":18,\"name\":\"张三\",\"sex\":\"男\"}";
 
        //JSON字符串转换成JSON对象
        JSONObject jsonObject1 = JSONObject.parseObject(userStr);
        System.out.println("JSON字符串转换成JSON对象\n" + jsonObject1);//{"sex":"男","name":"张三","age":18}
    }
}

6、JSON字符串–>Java对象

public class JSONTest{ 
   
    public static void main(String[] args) { 
   
        String userStr = "{\"age\":18,\"name\":\"张三\",\"sex\":\"男\"}";
 
        //JSON字符串转换成Java对象
        User user = JSONObject.parseObject(userStr, User.class);
        System.out.println("JSON字符串转换成Java对象\n" + user);//user {name='张三', sex='男', age=18}
    }
}