Java tutorial
/** * Copyright 2014 Confluent Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package io.confluent.rest.validation; import com.fasterxml.jackson.databind.JsonMappingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException; import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider; import javax.validation.ConstraintViolationException; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.MultivaluedMap; import javax.ws.rs.ext.Provider; import java.io.IOException; import java.io.InputStream; import java.lang.annotation.Annotation; import java.lang.reflect.Type; /** * Jackson provider that handles some additional exceptions. This allows additional processing and * validation of entities during parsing that don't fit well with the standard validation framework * (e.g. decoding of encoded fields to avoid storing the original and repeated decoding if the field * is accessed multiple times). */ @Provider public class JacksonMessageBodyProvider extends JacksonJaxbJsonProvider { public JacksonMessageBodyProvider() { setMapper(new ObjectMapper()); } public JacksonMessageBodyProvider(ObjectMapper mapper) { setMapper(mapper); } @Override protected boolean hasMatchingMediaType(MediaType mediaType) { return super.hasMatchingMediaType(mediaType) || (mediaType != null && mediaType.getType().equals("application") && mediaType.getSubtype().equals("octet-stream")); } @Override public Object readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException { try { return super.readFrom(type, genericType, annotations, mediaType, httpHeaders, entityStream); } catch (UnrecognizedPropertyException e) { throw ConstraintViolations.simpleException("Unrecognized field: " + e.getPropertyName()); } catch (JsonMappingException e) { // This needs to handle 2 JSON parsing error cases. Normally you would expect to see a // JsonMappingException because the data couldn't be parsed, but it can also occur when the // raw JSON is valid and satisfies the validation constraint annotations, but an exception is // thrown by the entity during construction. In the former case, we want to return a 400 // (Bad Request), in the latter a 422 (Unprocessable Entity) with a useful error message. We // don't want to expose just any exception message via the API, so this code specifically // detects ConstraintViolationExceptions that were thrown *after* the normal validation // checks, i.e. when the entity Java object was being constructed. Throwable cause = e.getCause(); if (cause instanceof ConstraintViolationException) { throw (ConstraintViolationException) cause; } throw e; } } }