Java tutorial
/* * Copyright 2002-2009 the original author or authors. * * 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. */ /* * Code copied into project from: * http://www.jarvana.com/jarvana/view/org/springframework/spring-web/3.0.0.RELEASE/spring-web-3.0.0.RELEASE-sources.jar!/org/springframework/http/converter/json/MappingJacksonHttpMessageConverter.java * to fix a linking problem. Modified only to add this attribution. */ package org.springframework.http.converter.json.replacement; import java.io.IOException; import java.nio.charset.Charset; import java.util.List; import org.springframework.http.HttpInputMessage; import org.springframework.http.HttpOutputMessage; import org.springframework.http.MediaType; import org.springframework.http.converter.AbstractHttpMessageConverter; import org.springframework.http.converter.HttpMessageNotReadableException; import org.springframework.http.converter.HttpMessageNotWritableException; import org.springframework.util.Assert; import com.fasterxml.jackson.core.JsonEncoding; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.databind.ObjectMapper; /** * Implementation of {@link org.springframework.http.converter.HttpMessageConverter HttpMessageConverter} that can read * and write JSON using <a href="http://jackson.codehaus.org/">Jackson's</a> {@link ObjectMapper}. * * <p>This converter can be used to bind to typed beans, or untyped {@link java.util.HashMap HashMap} instances. * * <p>By default, this converter supports {@code application/json}. This can be overridden by setting the {@link * #setSupportedMediaTypes(List) supportedMediaTypes} property. * method. * * @author Arjen Poutsma * @see org.springframework.web.servlet.view.json.BindingJacksonJsonView * @since 3.0 */ public class MappingJacksonHttpMessageConverter extends AbstractHttpMessageConverter<Object> { public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8"); private ObjectMapper objectMapper = new ObjectMapper(); private boolean prefixJson = false; /** Construct a new {@code BindingJacksonHttpMessageConverter}, */ public MappingJacksonHttpMessageConverter() { super(new MediaType("application", "json", DEFAULT_CHARSET)); } /** * Sets the {@code ObjectMapper} for this view. If not set, a default {@link ObjectMapper#ObjectMapper() ObjectMapper} * is used. * * <p>Setting a custom-configured {@code ObjectMapper} is one way to take further control of the JSON serialization * process. For example, an extended {@link org.codehaus.jackson.map.SerializerFactory} can be configured that provides * custom serializers for specific types. The other option for refining the serialization process is to use Jackson's * provided annotations on the types to be serialized, in which case a custom-configured ObjectMapper is unnecessary. */ public void setObjectMapper(ObjectMapper objectMapper) { Assert.notNull(objectMapper, "'objectMapper' must not be null"); this.objectMapper = objectMapper; } /** * Indicates whether the JSON output by this view should be prefixed with "{} &&". Default is false. * * <p> Prefixing the JSON string in this manner is used to help prevent JSON Hijacking. The prefix renders the string * syntactically invalid as a script so that it cannot be hijacked. This prefix does not affect the evaluation of JSON, * but if JSON validation is performed on the string, the prefix would need to be ignored. */ public void setPrefixJson(boolean prefixJson) { this.prefixJson = prefixJson; } @Override public boolean canRead(Class<?> clazz, MediaType mediaType) { return true; // JavaType javaType = TypeFactory.fromClass(clazz); // return objectMapper.canDeserialize(javaType) && isSupported(mediaType); } @Override public boolean canWrite(Class<?> clazz, MediaType mediaType) { // return objectMapper.canSerialize(clazz) && isSupported(mediaType); return true; } @Override protected boolean supports(Class<?> clazz) { // should not be called, since we override canRead/Write throw new UnsupportedOperationException(); } @Override protected Object readInternal(Class<? extends Object> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { return objectMapper.readValue(inputMessage.getBody(), clazz); } @Override protected void writeInternal(Object o, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException { JsonEncoding encoding = getEncoding(outputMessage.getHeaders().getContentType()); JsonGenerator jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(outputMessage.getBody(), encoding); if (prefixJson) { jsonGenerator.writeRaw("{} && "); } objectMapper.writeValue(jsonGenerator, o); } private JsonEncoding getEncoding(MediaType contentType) { if (contentType != null && contentType.getCharSet() != null) { Charset charset = contentType.getCharSet(); for (JsonEncoding encoding : JsonEncoding.values()) { if (charset.name().equals(encoding.getJavaName())) { return encoding; } } } return JsonEncoding.UTF8; } }