Im my app null values will not be serialized to json, and its ok. But in one specific case, I'd like to have null values send to client. How could I achieve that ?
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
for this class I tried with JsonInclude.Always but its defualt value that gets overriden in config later on.
Use JsonInclude annotation. Example:
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.databind.ObjectMapper;
public class Test {
public static void main(String[] args) throws Exception {
ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_NULL);
System.out.println(mapper.writeValueAsString(new User()));
}
}
@JsonInclude
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Above code prints:
{"name":null}
Default value in JsonInclude is ALWAYS:
/**
* Inclusion rule to use for instances (values) of types (Classes) or
* properties annotated.
*/
public Include value() default Include.ALWAYS;
Other option is to use JsonSerialize annotation:
@JsonSerialize(include = Inclusion.ALWAYS)
class User {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Result is the same as for JsonInclude.
