JAXRS 2.1 now enables declarative validation support by leveraging its integration with the Bean Validation API. This is done by using the constraint annotations for validating Beans, method parameters, and return values. These annotations can be placed on resource classes, fields and properties. For example, the following is a sample showing a User entity having a field level constraint of @NotNull. The same User class is then used as an argument to the resource method add which uses the @Valid annotation. A POST request would trigger the validation of the User entity field name to meet the @NotNull criteria:
class User {
@NotNull
private String name;
...
}
@Path("/")
class ResourceClass {
@POST public void add(@Valid User newUser) { ... }
}
Similar to the method parameter, the response can also be validated by applying constraints on the return type...
