Moxy 无法将 List<String> 编组为 JSON
Moxy can't marshal List<String> into JSON
我有一个 Tomcat 服务器 运行 一个使用 Jersey 2.6 框架的 servlet。在 servlet 中，我使用 Jackson 进行 JSON <--> POJO 编组。我最近了解到 Moxy 并正在尝试切换到它，因为 Jersey 似乎更喜欢它。
目前，我的 POM 中有以下内容：
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
<version>2.6</version>
</dependency>
我的一项 RESTful 服务如下：
@GET
@Path("threatSeverities")
@Produces(MediaType.APPLICATION_JSON)
public List<String> getThreatSeverities() {
return dc.selectAllSeverities();
}
这对 Jackson 来说效果很好。当我换成Moxy时，单元测试如下：
@Test
public void testThreatSeverities() {
final Response response = target("threatSeverities").request().get();
List<String> severities = response.readEntity(new GenericType<List<String>> () {});
assertNotNull(severities);
}
会产生以下错误：
org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=text/plain, type=interface java.util.List, genericType=java.util.List<java.lang.String>.
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:225)
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:149)
at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:853)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:812)
at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:377)
at org.glassfish.jersey.client.InboundJaxrsResponse.call(InboundJaxrsResponse.java:122)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:398)
at org.glassfish.jersey.client.InboundJaxrsResponse.readEntity(InboundJaxrsResponse.java:119)
at com.hp.it.scv.mobile.rest.RestTest.testThreatSeverities(RestTest.java:85)
at (... truncated)
有趣的是，即使控制器方法 getThreatSeverities 有一个 @Produces(MediaType.APPLICATION_JSON)，似乎 Moxy（或我不了解的其他东西）正在改变 Content-Type header 在单元测试中对 text/plain 的响应。 None 其中发生在杰克逊身上。
还有一点要注意，这似乎是 List<String> objects 特有的。 Moxy 编组 POJO 列表没有问题。
- Moxy 本身是否支持将
List<String> objects 编组为 JSON 字符串？似乎答案是否定的。我在网上找不到确凿的答案。我想知道我是否需要为 List<String> objects. 编写自己的 MessageBodyReader 和 MessageBodyWriter
- 是否有人知道在使用 Moxy 时可能会将
Content-Type header 更改为 text/plain？我怀疑它是 Moxy，也许是因为它看到我正在尝试 return 一个简单的字符串列表。
更新（2/2/2015）：
正如 peeskillet 所指出的，响应 returned 是一个 HTTP 500。我能够从响应中提取堆栈跟踪并得到以下：
Stack trace: javax.ws.rs.WebApplicationException: HTTP 500 Internal Server Error
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:810)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:263)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:250)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo(JsonWithPaddingInterceptor.java:103)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:88)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1154)
at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:571)
at org.glassfish.jersey.server.ServerRuntime$Responder.processResponse(ServerRuntime.java:378)
at org.glassfish.jersey.server.ServerRuntime$Responder.process(ServerRuntime.java:368)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:262)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
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:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:319)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1028)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:363)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:217)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.xml.bind.MarshalException - with linked exception:
[Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.]
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:403)
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:808)
... 25 more
Caused by: Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.marshalException(XMLMarshalException.java:97)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:911)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:848)
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:401)
... 26 more
Caused by: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.descriptorNotFoundInProject(XMLMarshalException.java:139)
at org.eclipse.persistence.internal.oxm.Context$ContextState.getSession(Context.java:143)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:787)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.Context.getSession(Context.java:451)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:356)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:568)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:1096)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:869)
... 28 more
从 Exception Description: A descriptor for class java.lang.String was not found in the project. 似乎 List<String> 到 JSON 如果不手动编写代码就不可能编组。
MOXy 代码 ( moxy/org.eclipse.persistence.moxy/src/org/eclipse/persistence/jaxb/rs/MOXyJsonProvider.java 中存在一些不明确的限制，这会阻止它处理 'java.*' 的集合类。我已经提出了这个问题。
我有一个 Tomcat 服务器 运行 一个使用 Jersey 2.6 框架的 servlet。在 servlet 中，我使用 Jackson 进行 JSON <--> POJO 编组。我最近了解到 Moxy 并正在尝试切换到它，因为 Jersey 似乎更喜欢它。
目前，我的 POM 中有以下内容：
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
<version>2.6</version>
</dependency>
我的一项 RESTful 服务如下：
@GET
@Path("threatSeverities")
@Produces(MediaType.APPLICATION_JSON)
public List<String> getThreatSeverities() {
return dc.selectAllSeverities();
}
这对 Jackson 来说效果很好。当我换成Moxy时，单元测试如下：
@Test
public void testThreatSeverities() {
final Response response = target("threatSeverities").request().get();
List<String> severities = response.readEntity(new GenericType<List<String>> () {});
assertNotNull(severities);
}
会产生以下错误：
org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=text/plain, type=interface java.util.List, genericType=java.util.List<java.lang.String>.
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:225)
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:149)
at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:853)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:812)
at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:377)
at org.glassfish.jersey.client.InboundJaxrsResponse.call(InboundJaxrsResponse.java:122)
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:398)
at org.glassfish.jersey.client.InboundJaxrsResponse.readEntity(InboundJaxrsResponse.java:119)
at com.hp.it.scv.mobile.rest.RestTest.testThreatSeverities(RestTest.java:85)
at (... truncated)
有趣的是，即使控制器方法 getThreatSeverities 有一个 @Produces(MediaType.APPLICATION_JSON)，似乎 Moxy（或我不了解的其他东西）正在改变 Content-Type header 在单元测试中对 text/plain 的响应。 None 其中发生在杰克逊身上。
还有一点要注意，这似乎是 List<String> objects 特有的。 Moxy 编组 POJO 列表没有问题。
- Moxy 本身是否支持将
List<String>objects 编组为 JSON 字符串？似乎答案是否定的。我在网上找不到确凿的答案。我想知道我是否需要为List<String>objects. 编写自己的 - 是否有人知道在使用 Moxy 时可能会将
Content-Typeheader 更改为text/plain？我怀疑它是 Moxy，也许是因为它看到我正在尝试 return 一个简单的字符串列表。
MessageBodyReader 和 MessageBodyWriter
更新（2/2/2015）：
正如 peeskillet 所指出的，响应 returned 是一个 HTTP 500。我能够从响应中提取堆栈跟踪并得到以下：
Stack trace: javax.ws.rs.WebApplicationException: HTTP 500 Internal Server Error
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:810)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:263)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:250)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo(JsonWithPaddingInterceptor.java:103)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:88)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1154)
at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:571)
at org.glassfish.jersey.server.ServerRuntime$Responder.processResponse(ServerRuntime.java:378)
at org.glassfish.jersey.server.ServerRuntime$Responder.process(ServerRuntime.java:368)
at org.glassfish.jersey.server.ServerRuntime.run(ServerRuntime.java:262)
at org.glassfish.jersey.internal.Errors.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:319)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1028)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:363)
at org.glassfish.grizzly.http.server.HttpHandler.run(HttpHandler.java:217)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.xml.bind.MarshalException - with linked exception:
[Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.]
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:403)
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:808)
... 25 more
Caused by: Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.marshalException(XMLMarshalException.java:97)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:911)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:848)
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:401)
... 26 more
Caused by: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.descriptorNotFoundInProject(XMLMarshalException.java:139)
at org.eclipse.persistence.internal.oxm.Context$ContextState.getSession(Context.java:143)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:787)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.Context.getSession(Context.java:451)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:356)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:568)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:1096)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:869)
... 28 more
从 Exception Description: A descriptor for class java.lang.String was not found in the project. 似乎 List<String> 到 JSON 如果不手动编写代码就不可能编组。
MOXy 代码 ( moxy/org.eclipse.persistence.moxy/src/org/eclipse/persistence/jaxb/rs/MOXyJsonProvider.java 中存在一些不明确的限制，这会阻止它处理 'java.*' 的集合类。我已经提出了这个问题。