使用 JAXB 从 XMLSchema.xsd 生成 Java 类

java jaxb

2022-09-02 03:05:06

我正在使用jaxb从xml模式中生成java类。架构导入 XMLSchema.xsd，其内容将用作文档中的元素。

如果我分别删除导入和对“xsd：schema”的引用，则绑定编译器会成功生成类。如果我不这样做，那么它将产生以下错误，如果我尝试仅从XMLSchema.xsd生成Java类，这些错误是相同的！

>  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.

答案 1

与这些东西作斗争，对我来说，这是区分大小写的问题，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，我使用的是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版本是，但这不适用于包装器元素，因此对于这些，您需要如上所述编写jaxb自定义，...如果你像我一样不幸，:)您可能需要使用 xsd 的本地副本并手动修复重复项。<args><arg>-B-XautoNameResolution</arg></args>

编辑为区分大小写的问题找到了另一种解决方案，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，希望这有帮助。

答案 2

您可以通过（至少）两种方法成功地让 JAXB 为 XML 模式 xsd 生成代码。您遇到的问题源于某些架构类型和元素共享相同的名称。

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。下面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（您可以应用其他转换，这些转换也可以正常工作，但我在文档中一遍又一遍地看到这种技术），但我认为它会产生丑陋的结果。例如，在本例中，有一个名为的生成类。ElementElement

第二种方法使用 xjc 输出所建议的类自定义。实际上，除了一个问题类之外，所有问题类都具有在相应的架构类型中设置的属性。因此，对我来说，在类名前面加上“抽象”是有意义的，即。其余类不是抽象的，但 named 会生成一个具有空主体的扩展类。因此，我称之为.以下是我使用的外部绑定定义：abstract="true"AbstractElementAttributexs:elementattributeBaseAttribute

<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的类名，并成功编译了架构。

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