一、前言

关于hibernate(3.0.1)源码包中org.hibernate.util.XMLHelper处理类， 分别创建createSAXReader基于org.dom4j.io.SAXReader解析器、创建createDOMReader基于org.dom4j.io.DOMReader解析器，详情参见代码说明部分。

二、源码说明 

1.XMLHelper类

package org.hibernate.util;@b@@b@import java.util.List;@b@import org.apache.commons.logging.Log;@b@import org.apache.commons.logging.LogFactory;@b@import org.dom4j.DocumentFactory;@b@import org.dom4j.Element;@b@import org.dom4j.io.DOMReader;@b@import org.dom4j.io.SAXReader;@b@import org.xml.sax.EntityResolver;@b@import org.xml.sax.ErrorHandler;@b@import org.xml.sax.SAXParseException;@b@@b@public final class XMLHelper@b@{@b@  private static final Log log = LogFactory.getLog(XMLHelper.class);@b@  public static final EntityResolver DEFAULT_DTD_RESOLVER = new DTDEntityResolver();@b@  private DOMReader domReader;@b@  private SAXReader saxReader;@b@@b@  public SAXReader createSAXReader(String file, List errorsList, EntityResolver entityResolver)@b@  {@b@    if (this.saxReader == null) this.saxReader = new SAXReader();@b@    this.saxReader.setEntityResolver(entityResolver);@b@    this.saxReader.setErrorHandler(new ErrorLogger(file, errorsList));@b@    this.saxReader.setMergeAdjacentText(true);@b@    this.saxReader.setValidation(true);@b@    return this.saxReader;@b@  }@b@@b@  public DOMReader createDOMReader()@b@  {@b@    if (this.domReader == null) this.domReader = new DOMReader();@b@    return this.domReader;@b@  }@b@@b@  public static Element generateDom4jElement(String elementName)@b@  {@b@    return DocumentFactory.getInstance().createElement(elementName);@b@  }@b@@b@  static Log access$000()@b@  {@b@    return log;@b@  }@b@@b@  public static class ErrorLogger@b@    implements ErrorHandler@b@  {@b@    private String file;@b@    private List errors;@b@@b@    ErrorLogger(String file, List errors)@b@    {@b@      this.file = file;@b@      this.errors = errors; }@b@@b@    public void error(SAXParseException error) {@b@      XMLHelper.access$000().error("Error parsing XML: " + this.file + '(' + error.getLineNumber() + ") " + error.getMessage());@b@      this.errors.add(error); }@b@@b@    public void fatalError(SAXParseException error) {@b@      error(error); }@b@@b@    public void warning(SAXParseException warn) {@b@      XMLHelper.access$000().warn("Warning parsing XML: " + this.file + '(' + warn.getLineNumber() + ") " + warn.getMessage());@b@    }@b@  }@b@}

 2.DTDEntityResolver类

package org.hibernate.util;@b@@b@import java.io.IOException;@b@import java.io.InputStream;@b@import java.io.ObjectInputStream;@b@import java.io.Serializable;@b@import org.apache.commons.logging.Log;@b@import org.apache.commons.logging.LogFactory;@b@import org.xml.sax.EntityResolver;@b@import org.xml.sax.InputSource;@b@@b@public class DTDEntityResolver@b@  implements EntityResolver, Serializable@b@{@b@  private static final Log log = LogFactory.getLog(DTDEntityResolver.class);@b@  private static final String URL = "http://hibernate.sourceforge.net/";@b@  private transient ClassLoader resourceLoader;@b@@b@  public DTDEntityResolver()@b@  {@b@    this.resourceLoader = super.getClass().getClassLoader();@b@  }@b@@b@  public DTDEntityResolver(ClassLoader resourceLoader)@b@  {@b@    this.resourceLoader = resourceLoader;@b@  }@b@@b@  public InputSource resolveEntity(String publicId, String systemId) {@b@    if ((systemId != null) && (systemId.startsWith("http://hibernate.sourceforge.net/"))) {@b@      log.debug("trying to locate " + systemId + " in classpath under org/hibernate/");@b@@b@      String path = "org/hibernate/" + systemId.substring("http://hibernate.sourceforge.net/".length());@b@      InputStream dtdStream = (this.resourceLoader == null) ? super.getClass().getResourceAsStream(path) : this.resourceLoader.getResourceAsStream(path);@b@@b@      if (dtdStream == null) {@b@        log.debug(systemId + " not found in classpath");@b@        return null;@b@      }@b@@b@      log.debug("found " + systemId + " in classpath");@b@      InputSource source = new InputSource(dtdStream);@b@      source.setPublicId(publicId);@b@      source.setSystemId(systemId);@b@      return source;@b@    }@b@@b@    return null;@b@  }@b@@b@  private void readObject(ObjectInputStream ois)@b@    throws IOException, ClassNotFoundException@b@  {@b@    ois.defaultReadObject();@b@    this.resourceLoader = super.getClass().getClassLoader();@b@  }@b@}