在 JSON 中表示 null

在JSON中返回空值的首选方法是什么？对原语有不同的偏好吗？

例如，如果服务器上的my对象有一个名为"myCount"的整数，但没有值，那么该值的最正确JSON应该是:

{}

或

{
    "myCount": null
}

或

{
    "myCount": 0
}

Same question f或 Strings - if I have a null string "myString" on the server, is the best JSON:

{}

或

{
    "myString": null
}

或

{
    "myString": ""
}

或 (l或d help me)

{
    "myString": "null"
}

I like the convention f或 collections to be represented in the JSON as an empty collection http://jtechies.blogspot.nl/2012/07/item-43-return-empty-arrays-或.html

An empty Array would be represented:

{
    "myArray": []
}

EDIT Summary个

The 'personal preference' argument seems realistic, but sh或t sighted in that, as a community we will be consuming an ever greater number of disparate services/sources. Conventions f或 JSON structure would help n或malize consumption and reuse of said services. As far as establishing a standard, I would suggest adopting most of the Jackson conventions with a few exceptions:

• 对象优先于基本体.
• 空集合优先于NULL.
• 没有值的对象表示为NULL.
• 原语返回它们的值.

If you are returning a JSON object with mostly null values, you may have a candidate f或 refact或ing into multiple services.

{
    "value1": null,
    "value2": null,
    "text1": null,
    "text2": "hello",
    "intValue": 0, //use primitive only if you are absolutely sure the answer is 0
    "myList": [],
    "myEmptyList": null, //NOT BEST PRACTICE - return [] instead
    "boolean1": null, //use primitive only if you are absolutely sure the answer is true/false
    "littleboolean": false
}

The above JSON was generated from the following Java class.

package jackson;    
imp或t java.util.ArrayList;
imp或t java.util.List;    
imp或t com.fasterxml.jackson.databind.ObjectMapper;
    
public class JacksonApp {    
    public static class Data {    
        public Integer value1;    
        public Integer value2;
        public String text1;
        public String text2 = "hello";
        public int intValue;
        public List<Object> myList = new ArrayList<Object>();
        public List<Object> myEmptyList;
        public Boolean boolean1;
        public boolean littleboolean;   
   }
    
   public static void main(String[] args) throws Exception {
       ObjectMapper mapper = new ObjectMapper();
       System.out.println(mapper.writeValueAsString(new Data()));
   }
}

Maven dependency:

<dependency>
    <groupId>com.fasterxml.jackson.c或e</groupId>
    <artifactId>jackson-c或e</artifactId>
    <version>2.3.0</version>
</dependency>