使用CXF对JAX-RS子资源进行Bean验证

Question

I try to use Bean Validation for my REST API with Apache CXF. I read Apache CXF Documentation and it works fine for root resources, but it doesn't work with sub resource locators . The constraints are ignored for sub resources.

Maven dependencies:

<dependency>
    <groupId>org.apache.cxf</groupId>
    <artifactId>cxf-rt-frontend-jaxrs</artifactId>
    <version>3.1.5</version>
</dependency>
<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>1.1.0.Final</version>
</dependency>
<dependency>
    <groupId>org.apache.bval</groupId>
    <artifactId>bval-jsr</artifactId>
    <version>1.1.0</version>
</dependency>

Java code:

@Named
@Path("test")
public class TestResource {

    @Inject
    private TestSubResource subResource;

    @Path("sub")
    public TestSubResource getSubResource() {
        return subResource;
    }

    @GET
    public void find(@NotNull @QueryParam("value") String value) {
    }
}

@Named
public class TestSubResource {

    @GET
    public void find(@NotNull @QueryParam("value") String value) {
    }
}

CXF configuration:

<bean id="validationProvider" class="org.apache.cxf.validation.BeanValidationProvider" />
<bean id="validationInInterceptor" class="org.apache.cxf.jaxrs.validation.JAXRSBeanValidationInInterceptor">
    <property name="provider" ref="validationProvider" />
</bean>
<jaxrs:server address="/rest" id="test" staticSubresourceResolution="true">
    <jaxrs:serviceBeans>
        <ref bean="testResource" />
    </jaxrs:serviceBeans>
    <jaxrs:inInterceptors>
        <ref bean="validationInInterceptor" />
    </jaxrs:inInterceptors> 
</jaxrs:server>

I found following issues:

• https://issues.apache.org/jira/browse/CXF-6297
• https://issues.apache.org/jira/browse/CXF-6296

but both are about validation of return value not about validation of request parameters.

The question CXF in Karaf: how to configure bean validation on subresources (preferably using Blueprint)? is similar, but about Karaf and Blueprint and contains no solution for my question.

Answer 1

I would say custom invoker is the way to go. But I guess you already knew that based on your comment.

<bean id="validationProvider" class="org.apache.cxf.validation.BeanValidationProvider" />
<bean id="validationInInterceptor"
    class="org.apache.cxf.jaxrs.validation.JAXRSBeanValidationInInterceptor">
    <property name="provider" ref="validationProvider" />
</bean>
<bean id="validationInvoker" class="org.apache.cxf.jaxrs.validation.JAXRSBeanValidationInvoker"></bean>

<jaxrs:server address="/rest" id="test"
    staticSubresourceResolution="true">
    <jaxrs:serviceBeans>
        <ref bean="testResource" />
    </jaxrs:serviceBeans>
    <jaxrs:inInterceptors>
        <ref bean="validationInInterceptor" />
    </jaxrs:inInterceptors>
    <jaxrs:invoker>
        <ref bean="validationInvoker" />
    </jaxrs:invoker>
</jaxrs:server>

I tried that on your example, and it works. But I think you need to use an ExceptionMapper , as you don't get proper exceptions. I think ValidationExceptionMapper would be the right one.

Edit- Updated exception mapper class based on comment

Answer 2

I don't think bean validation will work on the subresource, refer to the source code for BeanValidationInInterceptor , which is extended by JAXRSBeanValidationInInterceptor and is used as the validation interceptor. If you notice the method handleValidation , it is clear that the validation happens on the arguments of the resource object. Now, this validation is happening before the actual service method is invoked on the resource (that's how it is looking at least) and at this time, the subresource instance is not known (does not exist), so in general, subresource parameters at this juncture cannot be validated.

My impression is that with the current mechanism in CXF under discussion (interceptor), subresource parameters probably cannot be bean validated in the normal way.

You could probably take a workaround, with reference to the JAX-RS Reference , you could try to bean validate the parameter (especially if it is a request JSON), manually ie instantiate a Validator object and then validate it with that eg

package validator;

import java.util.Set;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import javax.validation.constraints.Max;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Pattern;

import org.apache.bval.jsr303.ApacheValidationProvider;

public class DataBean {

    @Max(10)
    public int x = 0;

    @Pattern(regexp= "this_string")
    public String y =  "this_string"; // also matches null

    public static void main(String[] args) {

        ValidatorFactory avf =
            Validation.byProvider(ApacheValidationProvider.class).configure().buildValidatorFactory();

        DataBean bean = new DataBean();
        Validator validator = avf.getValidator();

        Set<ConstraintViolation<DataBean>> violations = validator.validate(bean);

        System.out.println(violations);
    }

} // calss closing