Jersey REST客户端 - 将自定义MediaType视为MediaType.APPLICATION_JSON

Question

我正在编写一个REST客户端,使用Jersey 和JacksonFeature启用了一个Web服务,强制我指定他们的自定义内容类型,即使它只是普通的JSON.换句话说,当我这样做时:

Request request = buildMySampleRequestPojo();

Response response = requestBuilder.post(
        Entity.entity(request, MediaType.APPLICATION_JSON)
);

该服务抱怨我使用的内容类型无效.我可以通过指定自定义命名的媒体类型来代替MediaType.APPLICATION_JSON常量来解决这个问题:

Response response = requestBuilder.post(
        Entity.entity(request, "vnd.stupidNameThatReallyIsJustJSON+json")
);

但是,当我这样做时,我得到:

*SEVERE: MessageBodyWriter not found for media type=stupidNameThatReallyIsJustJSON*

有没有一种方法可以让Jersey对待这个自定义的媒体类型名称,就好像它是普通的JSON而不编写自定义的MessageBodyWriter？

Answer 1

我认为你可以使用这两个(JAX-RS实体提供者)和这个(使用杰克逊与泽西岛),以实现你想要的.简而言之,注册一个MessageBodyWriter注释,@Produces("application/vnd.stupidNameThatReallyIsJustJSON+json")并在实现中将编组/解组委托给杰克逊.

编辑:尝试一些类似的东西

package my.pack.age;

import com.sun.jersey.core.provider.AbstractMessageReaderWriterProvider;
import com.sun.jersey.core.util.ReaderWriter;

import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

@Produces("application/vnd.stupidNameThatReallyIsJustJSON+json")
public class MyJsonBodyWriter<T> extends AbstractMessageReaderWriterProvider<T> {

    // T should be your pojo in this case. If you can make your pojo compatible with org.codehaus.jettison.json.JSONObject,
    // then you can extend com.sun.jersey.json.impl.provider.entity.JSONObjectProvider and delegate all the methods of
    // MessageBodyWriter (and MessageBodyReader) to that. Otherwise just implement them.

    @Override
    public T readFrom(Class<T> type, Type genericType, Annotation annotations[], MediaType mediaType,MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException {
        try {
//            deserialize entityStream according to the given media type and return a new instance of T.
//            
//            You can do it like this (just an example) :
//            JSONObject myObject = new JSONObject();
//            try {
//                these names and values should come from the stream.
//                myObject.put("name", "Agamemnon");
//                myObject.put("age", 32);
//            } catch (JSONException ex) {
//                LOGGER.log(Level.SEVERE, "Error ...", ex);
//            }
            return null;
        } catch (Exception e) {
            throw new WebApplicationException(new Exception("Error during deserialization", e),400);
        }
    }

        @Override
    public void writeTo(T t,Class<?> type, Type genericType, Annotation annotations[], MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException {
        try {
            OutputStreamWriter writer = new OutputStreamWriter(entityStream, ReaderWriter.getCharset(mediaType));
            // write t on the writer
            writer.flush();
        } catch (Exception e) {
            throw new WebApplicationException( new Exception("Error during serialization", e), 500);
        }
    }

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        // should return true if this class can serialize the given type to the given media type
        return true;
    }

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        // should return true if this class can deserialize the given type to the given media type
        return true;
    }

    @Override
    public long getSize(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        // calculate and return content-lenght, i.e. the lenght of the serialized representation of t
        return 0;
    }

}

显然这只是一个起点,而不是一个工作的例子,但它应该给你足够的信息来启动.还要记住,您必须将该类注册到Jersey才能让它使用它.