https://github.com/bmarwell/jaxrs-jsonb-exceptionmapper

The JAX-RS spec does not specify ExceptionMappers for MessageBodyReader instances, the outcome will be dependent on the container. This example shows how to catch such an exception anyway.
https://github.com/bmarwell/jaxrs-jsonb-exceptionmapper

Last synced: 2 months ago
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The JAX-RS spec does not specify ExceptionMappers for MessageBodyReader instances, the outcome will be dependent on the container. This example shows how to catch such an exception anyway.

• Host: GitHub
• URL: https://github.com/bmarwell/jaxrs-jsonb-exceptionmapper
• Owner: bmarwell
• License: apache-2.0
• Created: 2020-08-14T10:46:11.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2020-08-14T13:10:28.000Z (almost 5 years ago)
• Last Synced: 2025-04-02T01:11:09.351Z (2 months ago)
• Language: Java
• Size: 21.5 KB
• Stars: 0
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.adoc
  • License: LICENSE

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README

        
= jaxrs-jsonb-exceptionmapper

The JAX-RS spec does not specify ExceptionMappers for MessageBodyReader instances, the outcome will be dependent on the container.

This example shows how to catch such an exception anyway.

== The problem

If you have a request body in a `@POST` request and want it to have parsed into a java value object, the MessageBodyReader supplied by your container vendor should take care of this.

However, the exception thrown on missing fields is dependent on the vendor’s implementation:

The exact signature is:

[source,java]

----

public T readFrom(

        Class type,

        Type genericType,

        Annotation[] annotations,

        MediaType mediaType,

        MultivaluedMap httpHeaders,

        InputStream entityStream) throws

    java.io.IOException,

    javax.ws.rs.WebApplicationException;

----

Now, the vendor can decide to wrap the `JsonbException` into a `WebApplicationException`.

Why is this important?

Well, now your `JsonbExceptionMapper` will not see the exception.

You will get an empty response entity, no matter how you define your `JsonbExceptionMapper`.

== The solution

At least for Open Liberty, a `BadRequestException` is thrown.

The idea here is to catch that exception, peek into the cause (if it exists) and map this exception.

== How to run this project

Execute `./mvnw clean liberty:dev`.

A OpenLiberty server will boot up with the application.

Just press `Enter` to execute the IT test case.

== Example implementations

=== OpenLiberty

Jsonb MessageBodyReader implementation: https://github.com/OpenLiberty/open-liberty/blob/integration/dev/com.ibm.ws.org.apache.cxf.cxf.rt.frontend.jaxrs.3.2/src/com/ibm/ws/jaxrs21/providers/json/JsonBProvider.java[jaxrs-2.1 JsonBProvider.java]

=== Payara

Jsonb MessageBodyReader implementation: https://github.com/payara/Payara/blob/master/appserver/ejb/ejb-http-remoting/endpoint/src/main/java/fish/payara/ejb/http/protocol/rs/JsonbInvokeMethodMessageBodyReader.java[rs JsonbInvokeMethodMessageBodyReader.java]