hajarrs/[email protected] (#17905)

Co-authored-by: hajar.qaibou_juliusbaer.com <[email protected]>

Author: hajarrs

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/controllers/AppUserController.java

@@ -0,0 +1,27 @@
+package com.baeldung.beanvalidation.application.controllers;
+
+import com.baeldung.beanvalidation.application.entities.AppUser;
+import com.baeldung.beanvalidation.application.repositories.AppUserRepository;
+import jakarta.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/app-users")
+public class AppUserController {
+
+    @Autowired
+    private AppUserRepository appUserRepository;
+
+    @PostMapping
+    public ResponseEntity<String> addAppUser(@Valid @RequestBody AppUser appUser, BindingResult result) {
+        if (result.hasErrors()) {
+            return new ResponseEntity<>(result.getFieldError().getDefaultMessage(), HttpStatus.BAD_REQUEST);
+        }
+        appUserRepository.save(appUser);
+        return new ResponseEntity<>("AppUser created successfully", HttpStatus.CREATED);
+    }
+}

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/entities/AppUser.java

@@ -0,0 +1,34 @@
+package com.baeldung.beanvalidation.application.entities;
+
+import jakarta.persistence.*;
+import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.Size;
+import com.baeldung.beanvalidation.application.validation.UserUnique;
+
+@Entity
+public class AppUser {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @NotEmpty(message = "Username is required")
+    @Size(min = 3, max = 50, message = "Username must be between 3 and 50 characters")
+    @UserUnique
+    private String username;
+
+    @NotEmpty(message = "Email is required")
+    @Email(message = "Email should be valid")
+    private String email;
+
+    // Getters and setters
+    public Long getId() { return id; }
+    public void setId(Long id) { this.id = id; }
+
+    public String getUsername() { return username; }
+    public void setUsername(String username) { this.username = username; }
+
+    public String getEmail() { return email; }
+    public void setEmail(String email) { this.email = email; }
+}

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/exception/GlobalExceptionHandler.java

@@ -0,0 +1,29 @@
+package com.baeldung.beanvalidation.application.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@ControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<Map<String, String>> handleValidationException(MethodArgumentNotValidException ex) {
+        Map<String, String> errors = new HashMap<>();
+
+        // Populate the map with field-specific error messages
+        ex.getBindingResult().getAllErrors().forEach(error -> {
+            String fieldName = ((FieldError) error).getField();
+            String errorMessage = error.getDefaultMessage();
+            errors.put(fieldName, errorMessage);
+        });
+
+        return new ResponseEntity<>(errors, HttpStatus.BAD_REQUEST);
+    }
+}

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/repositories/AppUserRepository.java

@@ -0,0 +1,10 @@
+package com.baeldung.beanvalidation.application.repositories;
+
+import com.baeldung.beanvalidation.application.entities.AppUser;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface AppUserRepository extends JpaRepository<AppUser, Long> {
+    AppUser findByUsername(String username);
+}

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/validation/UserUnique.java

@@ -0,0 +1,15 @@
+package com.baeldung.beanvalidation.application.validation;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+import java.lang.annotation.*;
+
+@Documented
+@Constraint(validatedBy = UserUniqueValidator.class)
+@Target({ ElementType.FIELD })
+@Retention(RetentionPolicy.RUNTIME)
+public @interface UserUnique {
+    String message() default "Username already exists";
+    Class<?>[] groups() default {};
+    Class<? extends Payload>[] payload() default {};
+}

spring-boot-modules/spring-boot-validation/src/main/java/com/baeldung/beanvalidation/application/validation/UserUniqueValidator.java

@@ -0,0 +1,17 @@
+package com.baeldung.beanvalidation.application.validation;
+
+import com.baeldung.beanvalidation.application.repositories.AppUserRepository;
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+import org.springframework.beans.factory.annotation.Autowired;
+
+public class UserUniqueValidator implements ConstraintValidator<UserUnique, String> {
+
+    @Autowired
+    private AppUserRepository appUserRepository;
+
+    @Override
+    public boolean isValid(String username, ConstraintValidatorContext context) {
+        return appUserRepository.findByUsername(username) == null;
+    }
+}

spring-boot-modules/spring-boot-validation/src/main/resources/application.properties

@@ -1 +1,10 @@
 spring.jpa.properties.hibernate.globally_quoted_identifiers=true
+
+spring.datasource.url=jdbc:h2:mem:testdb
+spring.datasource.driverClassName=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=password
+spring.jpa.hibernate.ddl-auto=update
+
+# Disable Hibernate validation
+spring.jpa.properties.jakarta.persistence.validation.mode=none