使用JAXB从XMLSchema.xsd生成Java类

Question

我正在使用jaxb从xml架构生成java类.模式导入XMLSchema.xsd,其内容用作文档中的元素.

如果我分别删除导入和对"xsd:schema"的引用,那么绑定编译器会成功生成类.如果我没有那么它会产生以下错误,如果我尝试仅从XMLSchema.xsd生成Java类,则会出现同样的错误!

>  C:\Users\me>"%JAXB%/xjc" -extension -d tmp/uisocketdesc -p uis.jaxb uisocketdesc.xsd -b xml_binding_test.xml -b xml_binding_test_2.xml
-b xml_binding_test_3.xml
parsing a schema...
compiling a schema...

> [ERROR] A class/interface with the same name "uis.jaxb.ComplexType" is already in use. Use a class customization to resolve this conflict.
 line 612 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "ComplexType" is generated from here.
 line 440 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] A class/interface with the same name "uis.jaxb.Attribute" is already in use. Use a class customization to resolve this conflict.
 line 364 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "Attribute" is generated from here.
 line 1020 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] A class/interface with the same name "uis.jaxb.SimpleType" is already in use. Use a class customization to resolve this conflict.
 line 2278 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "SimpleType" is generated from here.
 line 2222 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] A class/interface with the same name "uis.jaxb.Group" is already in use. Use a class customization to resolve this conflict.
 line 930 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "Group" is generated from here.
 line 727 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] A class/interface with the same name "uis.jaxb.AttributeGroup" is already in use. Use a class customization to resolve this conflict.
 line 1062 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "AttributeGroup" is generated from here.
 line 1026 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] A class/interface with the same name "uis.jaxb.Element" is already in use. Use a class customization to resolve this conflict.
 line 721 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Relevant to above error) another "Element" is generated from here.
 line 647 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 1020 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 364 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 2278 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 2222 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 930 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 727 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 440 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 612 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 1026 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 1062 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] Two declarations cause a collision in the ObjectFactory class.
 line 647 of "http://www.w3.org/2001/XMLSchema.xsd"

> [ERROR] (Related to above error) This is the other declaration.
 line 721 of "http://www.w3.org/2001/XMLSchema.xsd"

Failed to produce code.

Answer 1

同样也要打这样的东西,对我而言,它是区分大小写的问题,并且元素和属性问题的名称相同(有时通过继承).对于第二个问题,我正在使用包含以下内容的外部绑定文件:

<jaxb:bindings node="//xs:complexType[@name='AbstractGriddedSurfaceType']//xs:attribute[@name='rows']">
    <jaxb:property name="rowCount"/>
</jaxb:bindings>

对于区分大小写的问题,您可以使用xjc参数-XautoNameResolution,maven版本<args><arg>-B-XautoNameResolution</arg></args>,但这不适用于包装器元素,因此对于这些,您需要编写如上所述的jaxb自定义,...如果您不幸我喜欢我:)您可能需要使用xsd的本地副本并手动修复重复.

编辑 找到针对区分大小写问题的另一个解决方案,其中重命名元素是不够的:

<jaxb:bindings node=".//xs:element[@name='imageDatum'][@type='gml:ImageDatumPropertyType']">
    <jaxb:property name="imageDatumInst"/>
    <jaxb:factoryMethod name="imageDatumInst" />
</jaxb:bindings>

祝你好运,希望这会有帮助.

Answer 2

您可以通过(至少)两种方法成功地让JAXB为XML Schema xsd生成代码.您遇到的问题源于某些模式类型和元素共享相同名称的事实.

第一个选项通过将一个或多个XML名称转换应用于生成的类名来避免名称冲突.以下是将执行此操作的外部绑定文件的示例:

<jxb:bindings version="2.1"
               xmlns:jxb="http://java.sun.com/xml/ns/jaxb"
               xmlns:xs="http://www.w3.org/2001/XMLSchema"
               xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
               jxb:extensionBindingPrefixes="xjc">  
  <jxb:globalBindings>
    <xjc:simple/>   
  </jxb:globalBindings>   
  <jxb:bindings schemaLocation="XMLSchema.xsd">
    <jxb:schemaBindings>
      <jxb:nameXmlTransform>
        <jxb:elementName suffix="Element"/>
      </jxb:nameXmlTransform>
    </jxb:schemaBindings>
  </jxb:bindings>  
</jxb:bindings>

这种方法有效(您可以应用其他可以正常工作的转换,但我在文档中一遍又一遍地看到这种技术),但我认为它会产生难看的结果.例如,在这种情况下,生成的类被命名ElementElement.

第二种方法使用xjc输出建议的类定制.实际上,除了一个问题类之外的所有问题类都abstract="true"在相应的模式类型中设置了属性.因此,使用"Abstract"前缀类名是有道理的,即AbstractElement.剩下的Attribute类不是抽象的,但是xs:elementnamed会attribute生成一个带有空体的扩展类.所以我打电话给它BaseAttribute.这是我使用的外部绑定定义:

<jxb:bindings version="2.1"
               xmlns:jxb="http://java.sun.com/xml/ns/jaxb"
               xmlns:xs="http://www.w3.org/2001/XMLSchema"
               xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
               jxb:extensionBindingPrefixes="xjc">
  <jxb:globalBindings>
    <xjc:simple/>
  </jxb:globalBindings>
  <jxb:bindings schemaLocation="XMLSchema.xsd">
    <jxb:schemaBindings>
      <jxb:package name="org.w3.xmlschema"/>
    </jxb:schemaBindings>
    <jxb:bindings node="//xs:complexType[@name='complexType']">
      <jxb:class name="AbstractComplexType"/>
    </jxb:bindings> 
    <jxb:bindings node="//xs:complexType[@name='group']">
      <jxb:class name="AbstractGroup"/>
    </jxb:bindings> 
    <jxb:bindings node="//xs:complexType[@name='attributeGroup']">
      <jxb:class name="AbstractAttributeGroup"/>
    </jxb:bindings> 
    <jxb:bindings node="//xs:complexType[@name='simpleType']">
      <jxb:class name="AbstractSimpleType"/>
    </jxb:bindings> 
    <jxb:bindings node="//xs:complexType[@name='element']">
      <jxb:class name="AbstractElement"/>
    </jxb:bindings> 
    <jxb:bindings node="//xs:complexType[@name='attribute']">
      <jxb:class name="BaseAttribute"/>
    </jxb:bindings> 
  </jxb:bindings>
</jxb:bindings>

在我看来,这给出了更清晰的生成类名,并成功编译了模式.

我还建议对XMLSchema.xsd使用单独的编译并将其保存在jar文件中以供以后使用,以防在编译另一个模式时再次出现此问题.这个问题的答案描述了如何.

Answer 3

另一种选择是删除该-p选项，以便在不同的包中生成类

Answer 4

看来您的架构已损坏。XJC对这些事情非常挑剔，并且可能会在其他工具允许的事情上失败。

我发现首先通过AlphaWorks 模式质量检查器运行模式比挑选 XJC 的错误更容易。这提供了一个很好的、人类可读的（好吧，无论如何，开发人员可读的）错误输出。如果顺利通过，那么您通过 XJC 的机会也会大得多。