samaxes

I have already approached this subject twice in the past. First, on my post Integrating Bean Validation with JAX-RS in Java EE 6, describing how to use Bean Validation with JAX-RS in JBoss AS 7, even before this was defined in the Java EE Platform Specification. And later, on an article written for JAX Magazine and posteriorly posted on JAXenter, using the new standard way defined in Java EE 7 with Glassfish 4 server (the first Java EE 7 certified server).

Now that WildFly 8, previously know as JBoss Application Server, has finally reached the final version and has joined the Java EE 7 certified servers club, it’s time for a new post highlighting the specificities and differences between these two application servers, GlassFish 4 and WildFly 8.

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This article was first published on Java Advent Calendar.

Introduction to Bean Validation

JavaBeans Validation (Bean Validation) is a new validation model available as part of Java EE 6 platform. The Bean Validation model is supported by constraints in the form of annotations placed on a field, method, or class of a JavaBeans component, such as a managed bean.

Several built-in constraints are available in the javax.validation.constraints package. The Java EE 6 Tutorial lists all the built-in constraints.

Constraints in Bean Validation are expressed via Java annotations:

public class Person {
    @NotNull
    @Size(min = 2, max = 50)
    private String name;
    // ...
}

Bean Validation and RESTful web services

JAX-RS 1.0 provides great support for extracting request values and binding them into Java fields, properties and parameters using annotations such as @HeaderParam, @QueryParam, etc. It also supports binding of request entity bodies into Java objects via non-annotated parameters (i.e., parameters that are not annotated with any of the JAX-RS annotations). Currently, any additional validation on these values in a resource class must be performed programmatically.

The next release, JAX-RS 2.0, includes a proposal to enable validation annotations to be combined with JAX-RS annotations. For example, given the validation annotation @Pattern, the following example shows how form parameters could be validated.

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