Jackson entity is null when transcoding to JSON does not participate in serialization rollup

First join the dependency
<dependency>
   <groupId>com.google.code.gson</groupId>
   <artifactId>gson</artifactId>
</dependency>

Method One, use @JsonInclude on the entity (JsonInclude.Include.NON_NULL)

1, if placed on the property , if the property is null does not participate in serialization;
2, if placed on the class , that the entire properties of the class function;

Parameter meaning:

JsonInclude.Include.ALWAYS Default

The JsonInclude.Include.NON_DEFAULT property is not serialized as the default value

JsonInclude.Include.NON_EMPTY property is empty ("") or null is not serialized

JsonInclude.Include.NON_NULL property is NULL not serialized

Before using

After use

Method Two, if you do not want to add this every time, you can configure the global definition in APPLICATION.YML, this default is effective

Spring

Jackson

Default-property-inclusion:non_null

Method Three, through the Objectmapper object to set up, the following is the test case

@Test    public  void  Test () throws jsonprocessingexception {        Resultvo resultvo = new Resultvo ();        Resultvo.setcode (0);        Resultvo.setmsg ("Success");        Objectmapper mapper = new Objectmapper ();        Mapper.setserializationinclusion (JsonInclude.Include.ALWAYS);//default        String JSON = mapper.writevalueasstring ( RESULTVO);        SYSTEM.OUT.PRINTLN (JSON);        Mapper = new Objectmapper ();        Mapper.setserializationinclusion (JsonInclude.Include.NON_NULL); The property is null not serialized        JSON = mapper.writevalueasstring (RESULTVO);        SYSTEM.OUT.PRINTLN (JSON);    }

Print as follows:

{"code": 0, "msg": " success ", "data":null} {"code": 0, "msg": " success "}

Jackson entity is null when transcoding to JSON does not participate in serialization rollup