java - 获取 MessageBodyProviderNotFoundException : MessageBodyReader not found for media type=text/plain When output is JSON string

Question

我正在尝试调用 request.getEntity 返回自定义类型，但看起来它正在以文本/纯文本而不是 JSON 的形式获取响应，这给了我以下错误。我通过返回一个字符串来测试 get 输出，并且能够以字符串形式获取 json。我不知道为什么会发生这种情况。也许我缺少某种依赖？ get方法是使用https://github.com/mulesoft-labs/raml-java-client-generator生成的.

Exception in thread "main" org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=text/plain, type=class org.mule.example.resource.weatherdata.model.WeatherdataGETResponse, genericType=class org.mule.example.resource.weatherdata.model.WeatherdataGETResponse.
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:232)
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:156)
at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1085)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:853)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:785)
at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:326)
at org.glassfish.jersey.client.InboundJaxrsResponse$1.call(InboundJaxrsResponse.java:111)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:419)
at org.glassfish.jersey.client.InboundJaxrsResponse.readEntity(InboundJaxrsResponse.java:108)
at org.mule.example.resource.weatherdata.Weatherdata.get(Weatherdata.java:52)
at com.test.Run.main(Run.java:16)

--- 我的主要方法公共(public)类运行{

public static void main(String[] args) {
    WeatherdataGETQueryParam param = new WeatherdataGETQueryParam(-121.955236, 37.354108);
    WeatherdataGETHeader header = new WeatherdataGETHeader();
    header.setXMashapeKey("--some key---");
    WeatherdataGETResponse test =  MashapeWeatherAPIClient.create().weatherdata.get(param, header);
    System.out.println(test);


}

}

---我的获取命令

  public org.mule.example.resource.weatherdata.model.WeatherdataGETResponse get(WeatherdataGETQueryParam queryParameters, WeatherdataGETHeader headers) {
    WebTarget target = this.client.target(getBaseUri());
    if (queryParameters.getLng()!= null) {
        target = target.queryParam("lng", queryParameters.getLng());
    }
    if (queryParameters.getLat()!= null) {
        target = target.queryParam("lat", queryParameters.getLat());
    }
    final javax.ws.rs.client.Invocation.Builder invocationBuilder = target.request(MediaType.APPLICATION_JSON_TYPE);
    if (headers.getXMashapeKey()!= null) {
        invocationBuilder.header("x-mashape-key", headers.getXMashapeKey());
    }
    Response response = invocationBuilder.get();
    if (response.getStatusInfo().getFamily()!= Family.SUCCESSFUL) {
        Response.StatusType statusInfo = response.getStatusInfo();
        throw new MashapeWeatherAPIException(statusInfo.getStatusCode(), statusInfo.getReasonPhrase());
    }
    return response.readEntity(org.mule.example.resource.weatherdata.model.WeatherdataGETResponse.class);

}

我的依赖项

<properties>
    <jersey.version>2.17</jersey.version>
</properties>
<dependencies>
    <!--Jersey client-->
    <dependency>
        <groupId>org.glassfish.jersey.core</groupId>
        <artifactId>jersey-client</artifactId>
        <version>${jersey.version}</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>${jersey.version}</version>
    </dependency>

    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-multipart</artifactId>
        <version>${jersey.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.4.1</version>
    </dependency>
<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
    <version>2.24</version>
</dependency>       

    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.6</version>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
</dependencies>

Answer 1

让我们首先看看 Jersey JAX-RS 如何解析具有正确内容类型的 JSON 响应:application/json。当它收到这样的响应时，它会查找 javax.ws.rs.ext.MessageBodyReader 接口(interface)的任何可用实现，该接口(interface)注释为:

@Consumes(MediaType.APPLICATION_JSON)

这可以是任何实现，但对于我们的示例，我们将 MOXyJsonProvider 添加为项目的依赖项:

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

接下来，我们想让它也处理内容类型:文本/纯文本响应。为此，我们从 MOXyJsonProvider 继承自定义响应读取器，同时使用 MediaType.TEXT_PLAIN 对其进行注释:

@Provider
@Consumes(MediaType.TEXT_PLAIN)
public class MyCustomResponseReader extends MOXyJsonProvider {

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return genericType.equals(MyCustomClass.class);
    }

    @Override
    public Object readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, String> httpHeaders,
            InputStream entityStream) throws IOException, WebApplicationException {
        return super.readFrom(type, genericType, annotations, mediaType, httpHeaders, entityStream);
    }

}

请注意，在重写的 readFrom() 方法中，我们所做的只是调用父类 MOXyJsonProvider 的 super.readFrom() 。

最后，我们需要在将查询 Web 服务的 javax.ws.rs.client.Client 实例中注册自定义阅读器:

Client client = ClientBuilder.newBuilder().build().register(MyCustomResponseReader.class);

现在，文本/纯文本响应将像任何 application/json 响应一样被解析。

GitHub

完整的解决方案可以在 GitHub 上找到:PlainTextResponseReader

致谢

我基于以下资源中找到的信息构建了此解决方案:

堆栈溢出

• Create a text/plain Jersey response .
• How to register my custom MessageBodyReader in my CLIENT? .

其他

• Writing a custom MessageBodyReader to process POST body data with Jersey .