Difference between @Valid and @Validated in Spring

Understanding the Difference between @Valid and @Validated in Spring

If you have been working with Spring and using validation methods, you might have come across the annotations @Valid and @Validated. While both annotations serve the purpose of validating input parameters, they have some key differences that you need to be aware of. In this blog post, we will explore the differences between @Valid and @Validated, and help you understand when to use each one.

Before we dive into the details, let's have a quick look at these annotations in action:

@RequestMapping(value = "/object", method = RequestMethod.POST)
public @ResponseBody TestObject create(@Valid @RequestBody TestObject obj, BindingResult result) {
    // ...
}
@RequestMapping(value = "/object", method = RequestMethod.POST)
public @ResponseBody TestObject create(@Validated @RequestBody TestObject obj, BindingResult result) {
    // ...
}

As you can see, both annotations are used to validate the TestObject received as a request body. However, the difference lies in the actual validation framework each annotation is associated with.

@Valid - The JSR-303 Standard

The @Valid annotation is part of the JSR-303 Bean Validation specification. It is a standard for defining validation constraints for Java objects. When you use @Valid, you are instructing Spring to perform validation using the JSR-303 validation framework.

To use @Valid, you need to include a JSR-303 provider, such as Hibernate Validator, in your project's dependencies. This provider is responsible for actually applying the validation rules defined on your entities.

For example, if you have defined validation constraints on your TestObject class using JSR-303 annotations like @NotNull or @Size, the @Valid annotation will trigger the validation process based on these constraints.

@Validated - The Spring Validation Framework

On the other hand, the @Validated annotation is provided by the Spring Framework and is a variant of JSR-303's @Valid. While @Validated is designed for convenient use with Spring's JSR-303 support, it is not specific to JSR-303.

One of the key advantages of @Validated is its support for specification of validation groups. Validation groups allow you to define different groups of constraints and selectively apply validation rules based on these groups. This is particularly useful when you want to validate different aspects of an object in different scenarios.

For example, you can define a validation group for creating a new object and another group for updating an existing object. By using @Validated, you can specify which group of constraints to validate during a specific operation.

To use @Validated, you don't need to include a separate JSR-303 provider in your project. Spring's validation framework takes care of applying the validation rules.

So, which one should you use?

Now that we understand the differences, let's address the question of when to use each annotation.

If you solely rely on JSR-303 constraints and don't require validation groups, then @Valid is sufficient. It is more aligned with the standard specification and offers a wide range of validation constraints.

However, if you need to define validation groups or take advantage of Spring's additional features, such as Method-level validation, @Validated is the way to go. It provides better integration with the Spring ecosystem and gives you more flexibility when defining validation rules.

Conclusion

In summary, @Valid and @Validated are annotations used for validation in Spring, but they differ in terms of the underlying validation frameworks they are associated with and the features they offer.

By understanding the differences between @Valid and @Validated, you can make an informed decision on which annotation to use based on your validation requirements. Whether you choose to stick with the standard JSR-303 validation or take advantage of Spring's additional features, make sure to use the appropriate annotation in your code.

If you have any questions or need further clarification, feel free to leave a comment below. Happy coding! 😊

Have you ever been confused by @Valid and @Validated annotations in Spring? Check out this blog post to understand the differences and choose the right one for your validation needs! [Link to the blog post]