杰克逊使用JSON处理器，而无需使用说明 [英] Use Jackson JSON processor without using annotations

问题描述

我有一个包，它仅仅包括和XSD文件生成（通过JAXB）共享类这是有关我们的服务器和客户端应用程序。因此，这些类包含XML注释。

I have a package which just includes and xsd file to generate (via JAXB) shared classes which are relevant for our server and client applications. So these classes contain XML annotations.

一个客户端是一个Android应用程序。我也想，因为我用它提供了JSON（与新泽西州REST服务进行通信在这里使用这些类的JSON反序列化/ 杰克逊）。

One client is an Android App. I also want to use these classes here for JSON deserialization because I communicate with a REST service which delivers JSON (with Jersey/Jackson).

我尝试在Android这样使用杰克逊（版本1.7.2）：

I try to use Jackson (version 1.7.2) on the Android like this:

ObjectMapper mapper = new ObjectMapper();
mapper = mapper.configure(DeserializationConfig.Feature.USE_ANNOTATIONS,
                false);
mapper = mapper.configure(SerializationConfig.Feature.USE_ANNOTATIONS,
                false);
FooBar someObject = (FooBar) mapper.readValue(jsonString, FooBar.class);

我虽然配置映射器应避免使用注释，但我仍然获得

I though configure the MAPPER should avoid using annotations but I still get

02-07 09:30:18.631: ERROR/AndroidRuntime(447): java.lang.NoClassDefFoundError: javax.xml.bind.annotation.XmlAccessorType
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at java.lang.Class.getDeclaredAnnotations(Native Method)
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at org.codehaus.jackson.map.introspect.AnnotatedClass.resolveClassAnnotations(AnnotatedClass.java:292)
02-07 09:30:18.631: ERROR/AndroidRuntime(447):     at org.codehaus.jackson.map.introspect.AnnotatedClass.construct(AnnotatedClass.java:139)

谁知道的伎俩，从解决注释停止杰克逊。

Who knows the trick to stop Jackson from resolving annotations.

谢谢   克劳斯

推荐答案

我目前的调查导致这些结果：

My current investigations lead to these results:

在 DeserializationConfig.Feature.USE_ANNOTATIONS 属性的使用（设置为false）将导致杰克逊 DeserializerConfig 类使用 NopAnnotationIntrospector 。一类注释随后将使用该 NopAnnotationIntrospector 解决。该 NopAnnotationIntrospector 返回假每个 isHandled 要求任何注释一个类 - 在进一步的处理，实际上不会使用此批注

The usage of the DeserializationConfig.Feature.USE_ANNOTATIONS property (set to false) will cause the JACKSON DeserializerConfig class to use a NopAnnotationIntrospector. Annotations of a class will then be resolved using this NopAnnotationIntrospector. The NopAnnotationIntrospector will return false on each isHandled request for any annotation on a class - and in fact will not use this annotation in further processing.

所以 - 系统仍然考察的注解 - 它必须要在这种情况下，类路径。由于Android不提供任何JAXB-API说明这导致了的NoClassDefFoundError 。

So - the system still "inspects" the annotations - which have to be on the Classpath in this case. As Android does not provide any jaxb-api annotations this leads to the NoClassDefFoundError.

我预计 USE_ANNOTATIONS = FALSE 将带来JACKSON完全忽视任何注解 - 但不幸的是事实并非如此。我现在使用的杰克逊流API来解析使用JACKSON数据绑定功能的JSON字符串代替。

I expected USE_ANNOTATIONS = false would bring JACKSON to totally ignore any annotations - but unfortunately it does not. I will now use the Jackson Streaming API to parse the JSON string instead of using JACKSON Data Binding capabilities.

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