Snippet

Validating Request Data Transfer Objects

Validating input models ensures incoming payloads meet required structural and data-type constraints before processing. Bean Validation annotations like @NotBlank and @Min define constraints directly on class fields, encapsulating validation rules within the object definition.

snippet.java

java

public class CreateUserRequest {
 
    @NotBlank(message = "Username is mandatory")
    private String username;
 
    @Min(value = 18, message = "Age must be at least 18")
    private int age;
 
    public String getUsername() { return username; }
    public int getAge() { return age; }
}

spring

Breakdown

@NotBlank(message = "Username is mandatory")

Ensures the username field is not null and contains at least one non-whitespace character.

@Min(value = 18, message = "Age must be at least 18")

Constrains the integer age field to have a numerical value of 18 or greater.

public String getUsername() { return username; }

Encapsulated getter method providing read access to the validated username field.

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Validating Request Data Transfer Objects

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