Request DTO for input in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Request DTO in Spring Boot?

A Request DTO (Data Transfer Object) is a simple Java class used to carry data from the client to the server in a structured way. It helps separate input data from the internal model.

beginner

Why use a Request DTO instead of directly using entity classes?

Using a Request DTO keeps input data separate from database entities. This improves security, validation, and flexibility by controlling exactly what data the client can send.

beginner

How do you define a simple Request DTO class in Spring Boot?

Create a plain Java class with private fields, public getters and setters, and optionally validation annotations like @NotNull. This class represents the expected input structure.

beginner

What annotation is commonly used in Spring Boot controller methods to bind a Request DTO?

The @RequestBody annotation is used to tell Spring Boot to convert the incoming JSON request body into the Request DTO object.

intermediate

How can you validate a Request DTO automatically in Spring Boot?

Add validation annotations (like @NotNull, @Size) to the DTO fields and use @Valid on the controller method parameter. Spring Boot will check input and return errors if invalid.

What does a Request DTO represent in Spring Boot?

A Data sent from client to server

B Database entity

C Server response data

D Configuration settings

A Request DTO carries data from the client to the server.

Which annotation binds JSON input to a Request DTO in a controller?

A @RequestBody

B @Autowired

C @ResponseBody

D @Entity

@RequestBody tells Spring Boot to convert JSON input into the DTO.

Why should you avoid using entity classes directly as input objects?

A They are too small

B They lack getters and setters

C They expose internal data and reduce security

D They cannot be serialized

Using entities directly can expose internal data and cause security risks.

Which annotation is used to trigger validation on a Request DTO parameter?

A @Autowired

B @Valid

C @RequestParam

D @NotNull

@Valid triggers validation of the DTO fields based on annotations.

What happens if a Request DTO fails validation in Spring Boot?

A The server accepts the data anyway

B The server ignores the errors

C The server crashes

D The server returns a 400 Bad Request with error details

Spring Boot returns a 400 error with validation messages if input is invalid.

Explain what a Request DTO is and why it is useful in Spring Boot applications.

Think about how data travels from client to server and how to keep it safe.

Describe how to create and use a Request DTO in a Spring Boot controller method.

Focus on the steps from defining the class to receiving input in the controller.