Example of Spring Bean Validation – JSR-303 Annotations
Step 1: Set up a new Spring MVC project
- Create a new Maven project in your preferred IDE (e.g., IntelliJ or Eclipse or Spring Tool Suite) and add the following dependencies.
- Spring Web
- Lombok
- spring-boot-starter-validation
XML configuration in pom.xml file as shown below:
XML
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>3.2.0</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.spring</groupId> <artifactId>Spring_JSR</artifactId> <version>0.0.1-SNAPSHOT</version> <name>Spring_JSR</name> <description>Demo project for Spring_JSR</description> <properties> <java.version>17</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-validation</artifactId> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <excludes> <exclude> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </exclude> </excludes> </configuration> </plugin> </plugins> </build> </project> |
Project Structure:
Step 2: Create a Pojo class with JSR Annotations [Student]
Java
package com.demo.model; import jakarta.validation.constraints.AssertTrue; import jakarta.validation.constraints.Digits; import jakarta.validation.constraints.Email; import jakarta.validation.constraints.Min; import jakarta.validation.constraints.NotBlank; import jakarta.validation.constraints.NotEmpty; import jakarta.validation.constraints.NotNull; import jakarta.validation.constraints.Pattern; import jakarta.validation.constraints.Size; import lombok.Data; import org.hibernate.validator.constraints.URL; @Datapublic class Student { @NotNull @Size(min = 3, max = 50, message = "Name must be between three to fifty characters") private String name; @Email(message = "Invalid email format") private String email; @NotNull(message = "Age cannot be null") @Min(value = 18, message = "Age must be greater than or equal to eighteen") private Integer age; @NotEmpty(message = "Address cannot be empty") private String address; @Pattern(regexp = "\\d{10}", message = "Phone number must be ten digits") private String phoneNumber; public Student( @NotNull @Size(min = 3, max = 50, message = "Name must be between three to fifty characters") String name, @Email(message = "Invalid email format") String email, @NotNull(message = "Age cannot be null") @Min(value = 18, message = "Age must be greater than or equal to eighteen") Integer age, @NotEmpty(message = "Address cannot be empty") String address, @Pattern(regexp = "\\d{10}", message = "Phone number must be 10 digits") String phoneNumber) { super(); this.name = name; this.email = email; this.age = age; this.address = address; this.phoneNumber = phoneNumber; } } |
Step 3: Create a Controller that handles all validations [StudentController]
Java
package com.demo.controller; import com.demo.model.Student; import jakarta.validation.Valid; import java.util.List; import org.springframework.validation.BindingResult; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestControllerpublic class StudentController { @PostMapping("/student") public String createUser(@RequestBody @Valid Student student, BindingResult bindingResult) { if (bindingResult.hasErrors()) { return "Validation errors: " + bindingResult.getAllErrors(); } return "Student created successfully: " + student.toString(); } } |
Step 4: Run the Application
- Now you can run the spring boot application from IDE or command line.
mvn spring-boot:run
- Visit http://localhost:8080/students in tools like curl, Postman,, and you should see the courses page.
Here , we are using POSTMAN for Testing the application.
Output 1: Age is less than 18
Output 2: Name is NotNull and Size of name is between 3 and 50 characters
Output 3: Email is Incorrect
Output 4: If the all fields are in correct format and passed the all requirement
Spring Bean Validation – JSR-303 Annotations
In this article, we’ll explore practical examples of how to apply JSR-303 annotations to your domain objects from basic annotations to advanced. So basically annotations provide a declarative way to configure Spring beans, manage dependencies, and define behaviors, reducing the need for boilerplate code and making your code more concise and expressive.
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