What is Lombok?
Lombok is a Java library that can automatically plug into your editor and build tools when defining Java classes.
If you write Lombok annotations (e.g. @Getter or @setter), you don’t need to write another Getter or Setter methods again.
With one annotation, your class has a fully featured builder.
IDE
In this tutorial, we will use Eclipse.
Source Code
You can refer to the source code below.
https://github.com/ZarLiHninn/Form-Submitting-Lombok-WebJars
Let’s start Lombok
We will show you how to use Lombok in our previous project which is Form Submitting with Spring Boot Validation.
Step 1. Download and Install
- Please download lombok.jar from https://projectlombok.org/download
- Open downloaded lombok.jar.
- Specify your Eclipse IDE location by clicking Specify location and then you can see your Eclipse location.
- Click Install/Update.
- And now, your installation is completed and restart Eclipse.
Step 2. Add Lombok dependency in pom.xml
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <scope>provided</scope> </dependency> Step 3. Add Lombok annotation in Student.class
This is the code before using lombok.
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package com.reytech.demo.model; import java.time.LocalDate; import java.util.List; import javax.validation.constraints.Email; import javax.validation.constraints.Max; import javax.validation.constraints.NotEmpty; import javax.validation.constraints.NotNull; import javax.validation.constraints.Past; import javax.validation.constraints.Positive; import javax.validation.constraints.Size; import org.springframework.format.annotation.DateTimeFormat; public class Student { @NotEmpty(message = "{validation.name.NotEmpty}") @Size(min = 2, max = 50, message = "{validation.name.Size}") private String name; @NotNull(message = "{validation.age.NotNull}") @Positive(message = "{validation.age.Positive}") @Max(value = 18, message = "{validation.age.Maximum}") private Integer age; @NotEmpty(message = "{validation.email.NotEmpty}") @Email(message = "{validation.email.Type}") private String email; @NotEmpty(message = "{validation.subjects.NotEmpty}") private List <String> subjects; @NotNull(message = "{validation.birthDate.NotNull}") @Past(message = "{validation.birthDate.Past}") @DateTimeFormat(pattern = "yyyy-MM-dd") private LocalDate birthDate; @NotEmpty(message = "{validation.gender.NotEmpty}") private String gender; public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public LocalDate getBirthDate() { return birthDate; } public void setBirthDate(LocalDate birthDate) { this.birthDate = birthDate; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public List <String> getSubjects() { return subjects; } public void setSubjects(List <String> subjects) { this.subjects = subjects; } } This is the code by adding Lombok annotation.
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package com.reytech.demo.model; import java.time.LocalDate; import java.util.List; import javax.validation.constraints.Email; import javax.validation.constraints.Max; import javax.validation.constraints.NotEmpty; import javax.validation.constraints.NotNull; import javax.validation.constraints.Past; import javax.validation.constraints.Positive; import javax.validation.constraints.Size; import org.springframework.format.annotation.DateTimeFormat; import lombok.Getter; import lombok.Setter; @Getter @Setter public class Student { @NotEmpty(message = "{validation.name.NotEmpty}") @Size(min = 2, max = 50, message = "{validation.name.Size}") private String name; @NotNull(message = "{validation.age.NotNull}") @Positive(message = "{validation.age.Positive}") @Max(value = 18, message = "{validation.age.Maximum}") private Integer age; @NotEmpty(message = "{validation.email.NotEmpty}") @Email(message = "{validation.email.Type}") private String email; @NotEmpty(message = "{validation.subjects.NotEmpty}") private List <String> subjects; @NotNull(message = "{validation.birthDate.NotNull}") @Past(message = "{validation.birthDate.Past}") @DateTimeFormat(pattern = "yyyy-MM-dd") private LocalDate birthDate; @NotEmpty(message = "{validation.gender.NotEmpty}") private String gender; } - @Getter and @setter will generate getters and setters according to each field.
- And, we will explain the most usable Lombok annotations which are:
| Lombok annotation | Explanation |
|---|---|
| @data | It is all in one annotation which is equivalent to the combination of @Getter @setter @RequiredArgsConstructor @ToString @EqualsAndHashCode. |
| @Value | It is all in one annotation which is equivalent to the combination of @Getter @FieldDefaults(makeFinal=true, level=AccessLevel.PRIVATE) @AllArgsConstructor @ToString @EqualsAndHashCode. |
| @NoArgsConstructor | It is to generate default constructor with no arguments |
| @RequiredArgsConstructor | It is to generate a constructor with required arguments |
| @ AllArgsConstructor | It is to generate a constructor with all fields respectively |
| @ToString | It is to generate the toString method automatically |
| @RequiredArgsConstructor | It is to generate a constructor with required arguments |
| @EqualsAndHashCode | It is to generate HashCode and equals implementations from the fields of your object. |
| @builder | It is to generate the code automatically using Builder pattern for our class or constructor or method. |
Top comments (2)
Nice introduction.
I would suggest also adding the @Value annotation to your list. A lot like @Data, but instead it treats the object as immutable, so no setters, and some restriction on constructors and fields. I use it even more than @Data, to help keep a more clean object API that isn't polluted with unintended getters.
Thank you for your suggestion!