In this short post, I’d like to share with you how to use the @JsonProperty annotation provided by FasterXML/Jackson - the Java JSON library - to set custom name/logical name of properties present in the JSON document in response body.

The @JsonProperty annotation can be used at both field level and method level, and it has some optional parameters.

Consider the following DTO class:

public class LocationDTO {

	private String code;
	
	private String cityName;
	
	private String regionName;

	private String countryName;

	private String countryCode;
	
	private boolean enabled;
	
	// getters and setters are not shown for brevity
	
}

By default, the field names will be property names in the JSON object. So a GET API call will produce the following JSON:

{
  "code": "NYC_USA",
  "enabled": true,
  "cityName": "New York City",
  "regionName": "New York",
  "countryName": "United States of America",
  "countryCode": "US"
}

What if we want to have the property names city_name instead of cityName, region_name instead of regionName, and similar for the fields countryName and countryCode? In a Java/Spring project that uses Jackson library, we can use the @JsonProperty annotation like this:

@JsonProperty("city_name")
private String cityName;

So let’s update the DTO class above:

public class LocationDTO {
	private String code;
	
	@JsonProperty("city_name")
	private String cityName;
	
	@JsonProperty("region_name")
	private String regionName;

	@JsonProperty("country_name")
	private String countryName;

	@JsonProperty("country_code")
	private String countryCode;
	
	private boolean enabled;

	// getters and setters are not shown for brevity	
}

Hence the following output:

{
  "code": "NYC_USA",
  "city_name": "New York City",
  "region_name": "New York",
  "country_code": "US",
  "country_name": "United States of America",
  "enabled": true
}

You can also use the @JsonProperty annotation at method level - getter and setter both work. For example:

@JsonProperty("city_name")
public String getCityName() {
	return cityName;
}


@JsonProperty("region_name")
public void setRegionName(String regionName) {
	this.regionName = regionName;
}

Those are some examples of using @JsonProperty annotation to set JSON custom property name in Java/Spring project using Jackson library. To learn more about this annotation, check the Javadocs link below.

Also watch the video below to see how I use the @JsonProperty annotation in a real life project:

 

Reference:

                Annotation Type JsonProperty

 

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