Java 未找到 Media type=application/json 的 MessageBodyReader
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MessageBodyReader not found for media type=application/json
提问by
I have wrote a JAX-RS server and client both use Jersey. I want to sent a collection of my entities to client and I made this steps:
我写了一个 JAX-RS 服务器和客户端都使用 Jersey。我想将我的实体集合发送给客户，我做了以下步骤：
- Made entity extends Serializable
- Wrote a custom provider and extended it to support a collections
- Copy-paste entity and provider to client side
- 使实体扩展可序列化
- 编写了一个自定义提供程序并将其扩展为支持集合
- 将实体和提供者复制粘贴到客户端
I make a request, it sucessfully handled on the server side by client receives an error:
我提出一个请求，它在服务器端成功处理，客户端收到一个错误：
org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=interface java.util.List, genericType=java.util.List<model.HotelsEntity>.
org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:225)
org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:149)
org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:853)
org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:812)
org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:377)
org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:813)
org.glassfish.jersey.client.JerseyInvocation.access0(JerseyInvocation.java:90)
org.glassfish.jersey.client.JerseyInvocation.call(JerseyInvocation.java:693)
org.glassfish.jersey.internal.Errors.process(Errors.java:315)
org.glassfish.jersey.internal.Errors.process(Errors.java:297)
org.glassfish.jersey.internal.Errors.process(Errors.java:228)
org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:689)
org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:405)
org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:301)
service.HotelService.getHotels(HotelService.java:30)
actions.HotelAction.perform(HotelAction.java:42)
MainServlet.processResponse(MainServlet.java:33)
MainServlet.doPost(MainServlet.java:22)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
Server:
服务器：
@GET
@Produces(MediaType.APPLICATION_JSON)
public Response getHotelsList(@QueryParam("startDate") String startDate,
@QueryParam("endDate") String endDate) {
List<HotelsEntity> list = hotelService.getAll();
return ResponseFactory.response(Response.Status.OK, list);
}
Client:
客户：
GenericType<List<HotelsEntity>> genericType = new GenericType<List<HotelsEntity>>(){};
WebTarget target = client.target(preparePath());
List<HotelsEntity> hotels = target.request(MediaType.APPLICATION_JSON_TYPE).get(genericType);
Provider:
供应商：
public class JsonProvider<T> implements MessageBodyReader<T>, MessageBodyWriter<T> {
@Override
public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
return MediaType.APPLICATION_JSON.equals(mediaType.getType()) &&
MediaType.APPLICATION_JSON.equals(mediaType.getSubtype());
}
@Override
public T readFrom(Class<T> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException, WebApplicationException {
Gson gson = createGson();
Reader reader = new InputStreamReader(entityStream, Charset.forName(Constants.UTF_8));
return gson.fromJson(reader, genericType);
}
@Override
public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
return MediaType.APPLICATION_JSON.equals(mediaType.getType()) &&
MediaType.APPLICATION_JSON.equals(mediaType.getSubtype());
}
@Override
public long getSize(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
return -1;
}
@Override
public void writeTo(T t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
Gson gson = createGson();
JsonElement element = gson.toJsonTree(entityStream);
Writer writer = null;
try {
writer = new OutputStreamWriter(entityStream, Charset.forName(Constants.UTF_8));
gson.toJson(element, writer);
} finally {
if (writer != null) {
writer.flush();
}
}
}
private Gson createGson() {
return new GsonBuilder().setPrettyPrinting().create();
}
}
}
@Provider
public class JsonCollection extends JsonProvider<Collection<? extends HospitalityEntity>> {}
@Entity
@Table(name = "hotels", schema = "", catalog = "mydb")
public class HotelsEntity implements HospitalityEntity{
private int idHotel;
private String name;
private String region;
private String description;
@Id
@Column(name = "id_hotel")
public int getIdHotel() {
return idHotel;
}
public void setIdHotel(int idHotel) {
this.idHotel = idHotel;
}
@Basic
@Column(name = "name")
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Basic
@Column(name = "region")
public String getRegion() {
return region;
}
public void setRegion(String region) {
this.region = region;
}
@Basic
@Column(name = "description")
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
HotelsEntity that = (HotelsEntity) o;
if (idHotel != that.idHotel) return false;
if (description != null ? !description.equals(that.description) : that.description != null) return false;
if (name != null ? !name.equals(that.name) : that.name != null) return false;
if (region != null ? !region.equals(that.region) : that.region != null) return false;
return true;
}
@Override
public int hashCode() {
int result = idHotel;
result = 31 * result + (name != null ? name.hashCode() : 0);
result = 31 * result + (region != null ? region.hashCode() : 0);
result = 31 * result + (description != null ? description.hashCode() : 0);
return result;
}
}
回答by blacharnia
Your entity class does not have an empty constructor, which is needed for the JAX-RS unmarshalling.
您的实体类没有空构造函数，这是 JAX-RS 解组所需的。
Have a look here:
看看这里：
https://blogs.oracle.com/groundside/entry/jax_rs_2_0_messagebodyreader
https://blogs.oracle.com/groundside/entry/jax_rs_2_0_messagebodyreader
回答by brokethebuildagain
Sorry to resurrect this post, but I was having this problem with a Maven project and found that I needed to include a dependency for Hymanson-jaxrs-json-providerin my pom:
很抱歉重新发布这篇文章，但我在 Maven 项目中遇到了这个问题，发现我需要Hymanson-jaxrs-json-provider在我的 pom 中包含一个依赖项：
<dependency>
<groupId>com.fasterxml.Hymanson.jaxrs</groupId>
<artifactId>Hymanson-jaxrs-json-provider</artifactId>
<version>2.4.1</version>
</dependency>
MVN Repository: http://mvnrepository.com/artifact/com.fasterxml.Hymanson.jaxrs/Hymanson-jaxrs-json-provider
MVN 存储库：http: //mvnrepository.com/artifact/com.fasterxml.Hymanson.jaxrs/Hymanson-jaxrs-json-provider
回答by Denis535
You can use jersey json library:
您可以使用球衣 json 库：
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-Hymanson</artifactId>
<version>2.22</version>
</dependency>
Or genson:
或genson：
<dependency>
<groupId>com.owlike</groupId>
<artifactId>genson</artifactId>
<version>1.3</version>
</dependency>
回答by brunocrt
Check if you are registering the media type for JSON support. Do you have jersey-media-moxyon your class-path? If not, add this dependency to your pom.xml, please check your jersey version, in this example I'm using Jersey 2 (2.24)
检查您是否正在为 JSON 支持注册媒体类型。你的课程路径上有jersey-media-moxy吗？如果没有，请将此依赖项添加到您的 pom.xml，请检查您的球衣版本，在此示例中我使用的是 Jersey 2 (2.24)
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
<version>2.24</version>
</dependency>
回答by Purushothaman
For Gradle, add the following dependency:
对于 Gradle，添加以下依赖项：
compile group: 'org.glassfish.jersey.media',
name : 'jersey-media-moxy',
version : '2.24.1'
回答by user1932890
This very same exception is also thrown by jersey-media-moxy for silly mistakes like using an @XmlAttributeannotation where you really need an @XmlElement. This was the case in my scenario, and this is something to look into especially if the problem only happens for certain classes but others work fine.
jersey-media-moxy 也会因为愚蠢的错误而抛出同样的异常，比如@XmlAttribute在真正需要@XmlElement. 在我的场景中就是这种情况，这是需要研究的，特别是如果问题只发生在某些类而其他类工作正常时。
回答by Hari Kiran
Adding this dependency has fixed my error while other suggested answers did not:
添加此依赖项修复了我的错误，而其他建议的答案没有：
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-jaxb</artifactId>
<version>${jersey2.version}</version>
</dependency>
