Json return data to the front end, to ignore the null attribute field

There are two main ways:

1. Add annotations on the return of class:
   @JsonInclude(JsonInclude.Include.NON_NULL)
   This annotation can be null attributes in the entity class automatically ignored.

2. Springboot project can modify the configuration file application.yml Global Auto ignored:

spring:
  jackson:
    default-property-inclusion: NON_NULL

3. Other methods such as via Gson tools or methods, in the form of annotated on the interface, is similar concept.