使用 Java 查找可以在 xml 模式中重复的项目 [英] Find items that can be repeated in an xml schema using Java

问题描述

我想从一个 XML 模式中推断出一对 (parentTag, childTag)，这样 parentTag 就可以包含多个 childTag作为直接孩子.

I want to deduce from an XML schema the couple (parentTag, childTag) such that it is allowed for parentTag to contain multiple instances of childTag as direct children.

手动执行此操作，我在架构中查找 maxOccurs 属性，查找元素标记和直接父项的标记.

Doing that by hand, I look for the maxOccurs attribute in the schema, look the element tag, and tag of the direct parent.

例如来自

<xs:complexType name="aType">
     <xs:sequence>
          <xs:element ref="B" maxOccurs="unbounded"/>
     </xs:sequence>
</xs:complexType>

<xs:element name="A" type="aType">
<xs:element name="ANOTHER" type="aType">

我应该得到一对(A,B) 和(ANOTHER,B).

我有一个工作解决方案，使用 XSLT 将我的模式转换为这样的 (parentTag, childTag) 对的列表.

I have a working solution using XSLT to convert my schema to a list of such (parentTag, childTag) couples.

在 Java 中有一种优雅的方法可以做到这一点吗?你会推荐哪个库来实现这个?

Is there an elegant way to do this in Java ? Which library would you recommend to implement this ?

推荐答案

为了在 Java 中处理 XML 模式(没有 XSLT)，我们使用 Xerces2 Java Parser:http://xerces.apache.org/xerces2-j/

To process XML schemas in Java (without XSLT), we use Xerces2 Java Parser: http://xerces.apache.org/xerces2-j/

可能需要以下包/类:

import org.w3c.dom.*;
import org.apache.xerces.xs.*;
import org.apache.xerces.dom.DOMXSImplementationSourceImpl;
import org.apache.xerces.impl.xs.util.StringListImpl;
import org.apache.xerces.util.XMLCatalogResolver;

然后，XSD 文件的处理过程如下:

Then, the processing of an XSD file goes like this:

// Obtain the XML Schema implementation
XSImplementation impl = (XSImplementation)
  (new DOMXSImplementationSourceImpl()).getDOMImplementation(XMLConstants.XSD_LOADER_NAME);

// Get schema loader
XSLoader schemaLoader = impl.createXSLoader (null);

// Optional. Specify error handler
DOMErrorHandler errorHandler = ....;
DOMConfiguration config = schemaLoader.getConfig();
config.setParameter("error-handler", errorHandler);

// Optional. Specify XML catalog resolver.
// This may be needed to redirect internal DTD/schema file references
XMLCatalogResolver catalogResolver = ...;
config.setParameter("resource-resolver", catalogResolver);

String xsdURI = ...; // the location of schema file

// read schema
XSModel xsModel = schemaLoader.loadURI(xsdURI);

// PROCESS SCHEMA (here, you can do anything you want)

XSNamedMap xsMap;

// process top-level element declarations
xsMap = xsModel.getComponents(XSConstants.ELEMENT_DECLARATION);
for (int i = 0; i < xsMap.getLength(); i ++)
{
  XSElementDeclaration xsElementDecl = (XSElementDeclaration) xsMap.item(i);
  ...
}

// process top-level type definitions
xsMap = xsModel.getComponents(XSConstants.TYPE_DEFINITION);
for (int i = 0; i < xsMap.getLength(); i ++)
{
  XSTypeDefinition xsTDef = (XSTypeDefinition) xsMap.item(i);
  ...
}

// process model group definitions
xsMap = xsModel.getComponents(XSConstants.MODEL_GROUP_DEFINITION);
for (int i = 0; i < xsMap.getLength(); i ++)
{
  XSModelGroupDefinition xsGroupDef = (XSModelGroupDefinition) xsMap.item(i);
  ...
}

...

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