What is the importance of @JsonFilter annotation in Java?-javaTutorial-php.cn

What is the importance of @JsonFilter annotation in Java?

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Release： 2023-09-12 16:25:02

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What is the importance of @JsonFilter annotation in Java?

@JsonFilter annotation is used to define custom filters to serialize Java objects. We need to use the FilterProvider class to define the filter and get the actual filter instance. Now configure the filter by assigning the FilterProvider to the ObjectMapper class.

Syntax

@Target(value={ANNOTATION_TYPE,TYPE,METHOD,FIELD,PARAMETER})
@Retention(value=RUNTIME)
public @interface JsonFilter

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In the example below, customFilter can be declared as a parameter of the @JsonFilter annotation, which only extracts the name and filters Drop the other attribute beans of a.

Example

import com.fasterxml.jackson.annotation.JsonFilter;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ser.FilterProvider;
import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
public class JsonFilterAnnotationTest {
   public static void main(String args[]) throws JsonProcessingException {
      ObjectMapper mapper = new ObjectMapper();
      FilterProvider filterProvider = new SimpleFilterProvider().addFilter("customFilter",   SimpleBeanPropertyFilter.filterOutAllExcept("empName"));
      String jsonString = mapper.writer(filterProvider).writeValueAsString(new FilterBean());
      System.out.println(jsonString);
   }
}
@JsonFilter("customFilter")<strong>
</strong>class FilterBean {
   public int empId = 110;
   public String empName = "Raja Ramesh";
   public String gender = "male";
}

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Output

{"empName":"Raja Ramesh"}

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