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RestEasy ExceptionMapper NotAllowedException序列化错误MediaType八位字节流

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我在这里介绍简单的休息服务，以说明我收到的异常 .

服务 A

@Path("/A")
public class ServiceA {

    @GET
    @Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
    public Response show() {
        return Response.ok(new User("John", "Doe")).build();
    }
}

模型：

User

@XmlRootElement
public class User {

    private String firstName;
    private String lastName;

    public User() {
    }

    public User(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

ErrorResponse

@XmlRootElement
public class ErrorResponse {

    private String errorType;
    private String errorMessage;

    public ErrorResponse() {
    }

    public ErrorResponse(String errorType, String errorMessage) {
        this.errorType = errorType;
        this.errorMessage = errorMessage;
    }

    public String getErrorType() {
        return errorType;
    }

    public void setErrorType(String errorType) {
        this.errorType = errorType;
    }

    public String getErrorMessage() {
        return errorMessage;
    }

    public void setErrorMessage(String errorMessage) {
        this.errorMessage = errorMessage;
    }
}

最后我的 ExceptionMapper 看起来像这样：

@Provider
public class GenericExceptionMapper implements ExceptionMapper<Exception> {

    private final Logger LOG = LoggerFactory.getLogger(GenericExceptionMapper.class);

    @Override
    public Response toResponse(Exception exception) {
        ErrorResponse errorResponse = new ErrorResponse(exception.getClass().getSimpleName(), exception.getMessage());

        if (exception instanceof WebApplicationException) {
            LOG.error("Type: {}", exception.getClass().getSimpleName());
            LOG.error("Message: {}", exception.getMessage());
            WebApplicationException webApplicationException = (WebApplicationException) exception;
            return Response.status(webApplicationException.getResponse().getStatus()).entity(errorResponse).build();
        }

        return Response.serverError().entity(errorResponse).build();
    }
}

在URI上调用GET我得到了正确的响应：

Accept: application/json
GET http://localhost:8080/exception-mapper-example/rest/A

{"firstName":"John","lastName":"Doe"}

但是在这个URI上调用POST我得到一个例外：

2017-01-13 16:53:46,859 ERROR [com.aizaz.samples.exceptionmapper.GenericExceptionMapper] (default task-35) Type: NotAllowedException
 2017-01-13 16:53:46,860 ERROR [com.aizaz.samples.exceptionmapper.GenericExceptionMapper] (default task-35) Message: RESTEASY003650: No resource method found for POST, return 405 with Allow header
 2017-01-13 16:53:46,860 ERROR [io.undertow.request] (default task-35) UT005023: Exception handling request to /exception-mapper-example/rest/A: org.jboss.resteasy.spi.UnhandledException: org.jboss.resteasy.core.NoMessageBodyWriterFoundFailure: Could not find MessageBodyWriter for response object of type: com.aizaz.samples.model.ErrorResponse of media type: application/octet-stream
at org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:180)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:199)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:221)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.jboss.resteasy.core.NoMessageBodyWriterFoundFailure: Could not find MessageBodyWriter for response object of type: com.aizaz.samples.model.ErrorResponse of media type: application/octet-stream
at org.jboss.resteasy.core.ServerResponseWriter.writeNomapResponse(ServerResponseWriter.java:66)
at org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:176)
... 32 more

Relevant part

Caused by: org.jboss.resteasy.core.NoMessageBodyWriterFoundFailure:
Could not find MessageBodyWriter for response object of type:
com.aizaz.samples.model.ErrorResponse of media type: application/octet-stream

由于媒体类型：application / octet-stream，显然序列化失败 .

我知道在构建响应时我可以明确指定媒体类型

Response.ok().type(MediaType.APPLICATION_JSON).build();

但我不想这样做;因为我接受JSON / XML Accept标头，并希望以JSON或XML格式发回适当的响应 .

  • 我怎样才能做到这一点？

  • 为什么在这种情况下使用媒体类型octet-stream创建响应？

我的意思是，如果我创建我的自定义异常，它由代码中描述的相同ExceptionMapper映射; Response对象不需要显式指定 MediaType .

如果有人能提供他/她宝贵的智慧，那将是非常好的

rest resteasy java-ee-7 wildfly-10

2 回答

  • 0

    如果自定义异常扩展 WebApplicationException ，如

    public class MyCustomException extends WebApplicationException

    对于异常处理和响应创建，不需要显式 ExceptionMapper<MyCustomerException> .

    ExceptionMapper可以非常有助于处理派生自 Exception （或其子类）但不是 WebApplicationException （及其子类）的异常（注意 WebApplicationException 也是 Exception 的子类）

    例如，ExceptionMapper可用于处理异常，例如 IllegalArgumentException 并创建响应 .

    在上述两种情况下，响应都可以根据Resource方法中指定的 @Produces 进行序列化 .

    然而，在查看RestEasy的spec实现后，我发现，即使对于 WebApplicationException （s），如果ExceptionMapper由其他服务提供 @Provided ，它将被触发 .

    resteasy-jaxrs:3.1.0.Final
class: ExceptionHandler
method: public Response handleException(HttpRequest request, Throwable e)

  // First try and handle it with a mapper
  if ((jaxrsResponse = executeExceptionMapper(e)) != null) {
     return jaxrsResponse;
  }

    所以要么我确保ExceptionMapper用于某些特定的异常，例如 ExceptionMapper<IllegalArgumentException> ，而不是像上面的代码_159419中那样捕获所有异常，或者只是返回响应，如下面的代码所示：

    if (exception instanceof WebApplicationException) {
    WebApplicationException webApplicationException = (WebApplicationException) exception;
    return webApplicationException.getResponse();
}

    不会发生序列化错误 . 为什么？因为框架会处理这个问题（基于 @Produces 注释，它将序列化基于 NON WebApplicationException的响应的响应 . 对于基于 WebApplicationException 的响应，如上所示，框架也会处理响应（因为从未使用过ErrorResponse实体）

    然而，这个票中提到的问题 . NotAllowedException 出现在规范实现代码 before 中，与URI相关联的方法被执行 . 因此， @Produces 注释不会生效，并且在对响应进行编组时，将使用默认的MediaType八位字节流 .

    resteasy-jaxrs:3.1.0.Final
class: SegmentNode
method: public Match match(List<Match> matches, String httpMethod, HttpRequest request)

    因此，虽然发生以下例外情况; DefaultOptionsMethodException NotAllowedException NotSupportedException NotAcceptableException

    请求属性 RESTEASY_CHOSEN_ACCEPT 未设置

    request.setAttribute(RESTEASY_CHOSEN_ACCEPT, sortEntry.getAcceptType());
  return sortEntry.match;

    当服务器尝试编写响应时，它找不到MediaType（因为我们在创建响应对象时从未设置过它）

    resteasy-jaxrs:3.1.0.Final
class: ServerResponseWriter
method: public static void writeNomapResponse(BuiltResponse jaxrsResponse, final HttpRequest request, ...

 if (jaxrsResponse.getEntity() != null && jaxrsResponse.getMediaType() == null) {
     setDefaultContentType(request, jaxrsResponse, providerFactory, method);
 }

    它试图从方法注释中设置它;如前所述从未设定，因为 NotAllowedException 发生在 RESTEASY_CHOSEN_ACCEPT 之前可能已经设定 .

    它找到一张外卡，因为没有指定接受头，因此设置了八位字节流

    resteasy-jaxrs:3.1.0.Final
class: ServerResponseWriter
method: protected static void setDefaultContentType(HttpRequest request, BuiltResponse ...
if (chosen.isWildcardType()) {
     chosen = MediaType.APPLICATION_OCTET_STREAM_TYPE;
}

    （这只是一个总结;对于详细步骤，我必须回到规范实现代码）

    因此，我必须指定一种mediatype . 这样做可以从 @Context 查看 HttpHeaders 以使其成为动态，或者如果在我的情况下 Headers 中没有指定任何内容，我提供默认的MediaType Application/XML 以进行序列化 .

    希望这有助于某人也面临同样的问题 .

    回复于
  • 0

    您可以使用 HttpHeaders 的JAX-RS API管理 ExceptionMapper 返回的相应格式，并获取请求实体的 MediaType ，参见javadoc：http://docs.oracle.com/javaee/7/api/javax/ws/rs/core/HttpHeaders.html#getMediaType--

    所以你的代码如下：

    @Provider
public class GenericExceptionMapper implements ExceptionMapper<Exception> {

    @Context
    private HttpHeaders m_headers;

    private final Logger LOG = LoggerFactory.getLogger(GenericExceptionMapper.class);

    @Override
    public Response toResponse(Exception exception) {
        ErrorResponse errorResponse = new ErrorResponse(exception.getClass().getSimpleName(), exception.getMessage());

        if (exception instanceof WebApplicationException) {
            LOG.error("Type: {}", exception.getClass().getSimpleName());
            LOG.error("Message: {}", exception.getMessage());
            WebApplicationException webApplicationException = (WebApplicationException) exception;
            return Response.status(webApplicationException.getResponse().getStatus()).entity(errorResponse).build();
        }

        return Response.serverError().entity(errorResponse).type(m_headers.getMediaType()).build();
    }
}
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