java / beginner
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
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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
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@NotBlank(message = "Username is mandatory")
Ensures the username field is not null and contains at least one non-whitespace character.
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@Min(value = 18, message = "Age must be at least 18")
Constrains the integer age field to have a numerical value of 18 or greater.
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public String getUsername() { return username; }
Encapsulated getter method providing read access to the validated username field.