DTO dan Pengesahan

public class UserDto {
  private String name;
  private int age;

  // getters and setters
  public String getName() { return name; }
  public void setName(String name) { this.name = name; }
  public int getAge() { return age; }
  public void setAge(int age) { this.age = age; }
}

import jakarta.validation.constraints.*;public class UserDto {
  @NotBlank
  private String name;
  @Min(0)
  private int age;

  // getters/setters omitted for brevity
}

import org.springframework.web.bind.annotation.*;import org.springframework.validation.annotation.*;import jakarta.validation.*;@RestController
@RequestMapping("/users")
class UserController {
  @PostMapping
  public String create(@Valid @RequestBody UserDto dto) {
    return "Received: " + dto.getName() + ", " + dto.getAge();
  }
}