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How to ignore the null and empty fields using the Jackson library in Java?
The Jackson is a library for Java and it has very powerful data binding capabilities and provides a framework to serialize custom java objects to JSON and deserialize JSON back to Java object. The Jackson library provides @JsonInclude annotation that controls the serialization of a class as a whole or its individual fields based on their values during serialization.
The @JsonInclude annotation contains below two values
- Include.NON_NULL: Indicates that only properties with not null values will be included in JSON.
- Include.NON_EMPTY: Indicates that only properties that are not empty will be included in JSON
Example
import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
public class IgnoreNullAndEmptyFieldTest {
public static void main(String[] args) throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
Employee employee = new Employee(115, null, ""); // passing null and empty fields
String result = mapper.writeValueAsString(employee);
System.out.println(result);
}
}
// Employee class
class Employee {
private int id;
@JsonInclude(Include.NON_NULL)
private String firstName;
@JsonInclude(Include.NON_EMPTY)
private String lastName;
public Employee(int id, String firstName, String lastName) {
super();
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}Output
{
"id" : 115
}
Updated on: 06-Jul-2020
1K+ Views
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