The correct approach is not to change the entity class (DO),

1. Create a new data transfer class (DTO), such as MemberDTO,

2. Write a method to convert DO into DTO. The data contained in a DTO may come from several DOs. For example, if you need to transfer Member data now, what if you need some attributes of other tables.

DO remains consistent with the database, and DTO remains consistent with external interactions, so that it can be flexibly adjusted when data or business changes.
Never use DO directly for data transmission, as this is not conducive to expansion

This has nothing to do with Mybatis, it should be a json serialization configuration issue.
I assume you are using SpringMVC+Jackson. The serialization configuration of Jackson is as follows:

You can take a look@JsonInclude的几个枚举变量对应的含义，个人认为最理想的应该是用NON_EMPTY，这个会把空对象、空数组也不输出（例如：{}, []）。但要注意的是：0也会被认为是EMPTY从而不输出（意味着所有没赋值或为0的int类型或IntegerNo objects will be output).

When converting an object to JSON (serialization process), if the value of a property of the object is null, the property will not participate in serialization, and the generated JSON result will not contain this property. The code is as follows:

public String toNotifyBody(NotifyBean bean) { HashMap map = new HashMap(); map.put("orderId", bean.orderId); map.put("title", bean.title); map.put("subject", bean.subject); map.put("operateType", bean.operateType); map.put("handlePerson", bean.handlePerson); map.put("extractPerson", bean.extractPerson); map.put("sla", bean.sla); return JSON.toJSONString(map); }

Put the above parameters in the map, and then call the json method JSON.toJSONString(), the null value will not be transmitted. Let's take a look at the implementation of the JSON.toJSONString() method.

public static final String toJSONString(Object object) { return toJSONString(object, new SerializerFeature[0]); } public static final String toJSONString(Object object, SerializerFeature... features) { SerializeWriter out = new SerializeWriter(); try { JSONSerializer serializer = new JSONSerializer(out); for (com.alibaba.fastjson.serializer.SerializerFeature feature : features) { serializer.config(feature, true); } serializer.write(object); return out.toString(); } finally { out.close(); } }

If there is no entity class, exposing data table fields is inevitable.

I don’t know what method you used to generate JSON, but theoretically, there should be a parameter that ignores null values. Look for it. If you really can’t find it, you can use regular expressions to remove the null attributes.

It is necessary to build the corresponding entity class, only display the content that needs to be displayed, and convert the data format (such as date to string, etc.)

You can use HashMap to accept mybatis query results