找不到媒体类型= application / json的MessageBodyReader

时间：2014-05-03 09:14:34

标签： java json jersey jax-rs

我写了一个JAX-RS服务器，客户端都使用Jersey。我想将我的实体集合发送给客户端，我做了这个步骤：

  1. Made实体扩展Serializable
  2. 写了一个自定义提供程序并将其扩展为支持集合
  3. 将实体和提供商复制粘贴到客户端

    4. 我发出请求，它在服务器端成功处理，客户端收到错误：

    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.access$600(JerseyInvocation.java:90)
org.glassfish.jersey.client.JerseyInvocation$3.call(JerseyInvocation.java:693)
org.glassfish.jersey.internal.Errors.process(Errors.java:315)
org.glassfish.jersey.internal.Errors.process(Errors.java:297)
org.glassfish.jersey.internal.Errors.process(Errors.java:228)
org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:689)
org.glassfish.jersey.client.JerseyInvocation$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)

    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);
}

    客户端：

        GenericType<List<HotelsEntity>> genericType = new GenericType<List<HotelsEntity>>(){};
    WebTarget target = client.target(preparePath());
    List<HotelsEntity> hotels = target.request(MediaType.APPLICATION_JSON_TYPE).get(genericType);

    提供者：

    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;
}
}

8 个答案:

答案 0 :(得分：33)

你可以使用泽西json库：

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-json-jackson</artifactId>
    <version>2.22</version>
</dependency>

或者genson：

<dependency>
    <groupId>com.owlike</groupId>
    <artifactId>genson</artifactId>
    <version>1.3</version>
</dependency>

答案 1 :(得分：22)

很抱歉重新发布这篇文章，但我遇到了Maven项目的这个问题，发现我需要在我的pom中包含jackson-jaxrs-json-provider的依赖项：

<dependency>
    <groupId>com.fasterxml.jackson.jaxrs</groupId>
    <artifactId>jackson-jaxrs-json-provider</artifactId>
    <version>2.4.1</version>
</dependency>

MVN存储库：http://mvnrepository.com/artifact/com.fasterxml.jackson.jaxrs/jackson-jaxrs-json-provider

答案 2 :(得分：11)

您的实体类没有空构造函数，这是JAX-RS解组所需的。

看看这里：

https://blogs.oracle.com/groundside/entry/jax_rs_2_0_messagebodyreader

答案 3 :(得分：7)

检查您是否正在注册媒体类型以获取JSON支持。你的班级路径上有 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>

答案 4 :(得分：2)

对于Gradle，添加以下依赖项：

compile group: 'org.glassfish.jersey.media',
name         : 'jersey-media-moxy',
version      : '2.24.1'

答案 5 :(得分：0)

jersey-media-moxy还会因类似愚蠢的错误而抛出同样的异常，例如在您确实需要@XmlAttribute的地方使用@XmlElement注释。在我的情况下就是这种情况，这是值得研究的问题，尤其是当问题仅在某些类中发生而另一些类工作正常时。

答案 6 :(得分：0)

添加此依赖性已解决了我的错误，而其他建议的答案却没有：

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-jaxb</artifactId>
    <version>${jersey2.version}</version>
</dependency>

答案 7 :(得分：0)

是否可能具有以下依赖性：

jersey-common-2.25.1.jar
jersey-media-json-jackson-2.25.1.jar

...？

我在执行客户端剩余调用的丰富Java应用程序中拥有该功能。当我为此客户端组装可执行jar时，所有依赖项都将解压缩到一个jar文件中。原来，这两个文件都有一个文件org.glassfish.jersey.internal.spi.AutoDiscoverable ...具有不同的内容！

一切在我的IDE中都可以正常运行，一旦将其组装在一个罐子中，所需的内容就会被另一个罐子覆盖。

原来的解决方案是，如何声明依赖项中的顺序以及一些排除项。我将此放在列表的前面：

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>2.25.1</version>
        <exclusions>
            <exclusion>
                <groupId>org.glassfish.jersey.core</groupId>
                <artifactId>jersey-common</artifactId>
            </exclusion>
            <exclusion>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-annotations</artifactId>
            </exclusion>
        </exclusions>
</dependency>

后来我放了：

 <dependency>   
      <groupId>org.glassfish.jersey.core</groupId>
      <artifactId>jersey-common</artifactId>
      <version>2.25.1</version>
 </dependency>

我还从其他依赖项中排除了jersey-common的任何其他依赖项。 最好的祝福 弗雷德里克

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