How to change name of fields with @ToString annotation in Lombok
Overview
The @ToString annotation is one of the annotations in the project Lombok.
Note: Refer What is the @ToString annotation in Lombok? for the introduction of the annotation.
The @ToString annotation generates an implementation for the toString() method where the class name, along with each field in order, separated by commas, is printed. But sometimes, the names of the fields need to be different in the string representation of the fields.
For example, consider a Person class with three attributes, name, age, and address:
@ToString
@AllArgsConstructor
class Person {
private int age;
private String name;
private String address;
}
We define an instance of the Person class:
Person person = new Person(30, "sam", "US");
The default string representation of the above object is as follows:
Person(age=30, name=sam, address=US)
The names of the fields are as defined in the class. If we want to change the names of the fields while printing, we do as follows:
Person(Username=sam, Country=US, Age=30)
name parameter
The name parameter of the Include interface of the ToString annotation is used to give a different name to fields in the string representation.
Code
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>test</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.22</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>Main</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>Explanation
-
Lines 1 and 2: We import the
AllArgsConstructorandToStringannotations. -
Lines 6 to 8: We define the
Personclass annotated with@AllArgsConstructorand@ToStringannotations. -
Lines 10 and 11: We define the
agefield withAge. -
Lines 13 and 14: We define the
namefield withUsername. -
Lines 16 and 17: We define the
addressfield withCountry. -
Line 22: We create an instance of the
Personclass. -
Line 23: We print the person instance created in line 22 to console.
