Java解析XML格式字符串返回Document类型对象

package com.yc.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.LinkedList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.crimson.tree.XmlDocument;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

/**
* Utilities methods to simplify dealing with JAXP & DOM XML parsing
*
* @author     <a href="mailto:[e-mail]">David E. Jones</a>
* @version    $Revision: 1.1 $
* @since      2.0
*/
public class UtilXml
{

public static final String module = UtilXml.class.getName();

public static String writeXmlDocument(Document document) throws java.io.IOException
{
if (document == null)
{
Debug.logWarning("[UtilXml.writeXmlDocument] Document was null, doing nothing", module);
return null;
}

ByteArrayOutputStream bos = new ByteArrayOutputStream();
writeXmlDocument(bos, document);
String outString = bos.toString("UTF-8");

if (bos != null)
bos.close();
return outString;
}

public static void writeXmlDocument(String filename, Document document) throws java.io.FileNotFoundException, java.io.IOException
{
if (document == null)
{
Debug.logWarning("[UtilXml.writeXmlDocument] Document was null, doing nothing", module);
return;
}
if (filename == null)
{
Debug.logWarning("[UtilXml.writeXmlDocument] Filename was null, doing nothing", module);
return;
}

File outFile = new File(filename);
FileOutputStream fos = null;
fos = new FileOutputStream(outFile);

try
{
writeXmlDocument(fos, document);
}
finally
{
if (fos != null)
fos.close();
}
}

public static void writeXmlDocument(OutputStream os, Document document) throws java.io.IOException
{
if (document == null)
{
Debug.logWarning("[UtilXml.writeXmlDocument] Document was null, doing nothing", module);
return;
}
if (os == null)
{
Debug.logWarning("[UtilXml.writeXmlDocument] OutputStream was null, doing nothing", module);
return;
}
//todo:xml序列化需要改进
//         if(document instanceof XmlDocument) {
//Crimson writer
         XmlDocument xdoc = (XmlDocument) document;
         xdoc.write(os);
//         }
//         else {
//        // Xerces writer
// OutputFormat format = new OutputFormat(document);
// format.setIndent(2);
//
// XMLSerializer serializer = new XMLSerializer(os, format);
// serializer.asDOMSerializer();
// serializer.serialize(document.getDocumentElement());
//         }
}

public static Document readXmlDocument(String content) throws SAXException, ParserConfigurationException, java.io.IOException
{
return readXmlDocument(content, true);
}

public static Document readXmlDocument(String content,String charSet) throws SAXException, ParserConfigurationException, java.io.IOException
{
return readXmlDocument(content, true,charSet);
}

public static Document readXmlDocument(String content, boolean validate) throws SAXException, ParserConfigurationException, java.io.IOException
{
if (content == null)
{
Debug.logWarning("[UtilXml.readXmlDocument] content was null, doing nothing", module);
return null;
}
ByteArrayInputStream bis = new ByteArrayInputStream(content.getBytes("UTF-8"));
return readXmlDocument(bis, validate, "Internal Content");
}

public static Document readXmlDocument(String content, boolean validate,String charSet) throws SAXException, ParserConfigurationException, java.io.IOException
{
if (content == null)
{
Debug.logWarning("[UtilXml.readXmlDocument] content was null, doing nothing", module);
return null;
}
ByteArrayInputStream bis = new ByteArrayInputStream(content.getBytes(charSet));
return readXmlDocument(bis, validate, "Internal Content");
}

public static Document readXmlDocument(URL url) throws SAXException, ParserConfigurationException, java.io.IOException
{
return readXmlDocument(url, true);
}

public static Document readXmlDocument(URL url, boolean validate) throws SAXException, ParserConfigurationException, java.io.IOException
{
if (url == null)
{
Debug.logWarning("[UtilXml.readXmlDocument] URL was null, doing nothing", module);
return null;
}
//        System.out.println(url);
return readXmlDocument(url.openStream(), validate, url.toString());
}

public static Document readXmlDocument(InputStream is) throws SAXException, ParserConfigurationException, java.io.IOException
{
return readXmlDocument(is, true, null);
}

public static Document readXmlDocument(InputStream is, boolean validate, String docDescription) throws SAXException, ParserConfigurationException, java.io.IOException
{
if (is == null)
{
Debug.logWarning("[UtilXml.readXmlDocument] InputStream was null, doing nothing", module);
return null;
}

Document document = null;
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(validate);
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
if (validate)
{
LocalResolver lr = new LocalResolver(new DefaultHandler());
ErrorHandler eh = new LocalErrorHandler(docDescription, lr);

builder.setEntityResolver(lr);
builder.setErrorHandler(eh);
}
document = builder.parse(is);
return document;
}

public static Document makeEmptyXmlDocument()
{
return makeEmptyXmlDocument(null);
}

public static Document makeEmptyXmlDocument(String rootElementName)
{
Document document = null;
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

factory.setValidating(true);
// factory.setNamespaceAware(true);
try
{
DocumentBuilder builder = factory.newDocumentBuilder();

document = builder.newDocument();
}
catch (Exception e)
{
Debug.logError(e, module);
}

if (document == null)
return null;

if (rootElementName != null)
{
Element rootElement = document.createElement(rootElementName);
document.appendChild(rootElement);
}

return document;
}

/** Creates a child element with the given name and appends it to the element child node list. */
public static Element addChildElement(Element element, String childElementName, Document document)
{
Element newElement = document.createElement(childElementName);

element.appendChild(newElement);
return newElement;
}

/** Creates a child element with the given name and appends it to the element child node list.
*  Also creates a Text node with the given value and appends it to the new elements child node list.
*/
public static Element addChildElementValue(Element element, String childElementName, String childElementValue, Document document)
{
Element newElement = addChildElement(element, childElementName, document);

newElement.appendChild(document.createTextNode(childElementValue));
return newElement;
}

/** Creates a child element with the given name and appends it to the element child node list.
*  Also creates a CDATASection node with the given value and appends it to the new elements child node list.
*/
public static Element addChildElementCDATAValue(Element element, String childElementName, String childElementValue, Document document)
{
Element newElement = addChildElement(element, childElementName, document);

newElement.appendChild(document.createCDATASection(childElementValue));
return newElement;
}

/** Return a List of Element objects that have the given name and are
* immediate children of the given element; if name is null, all child
* elements will be included. */
public static List childElementList(Element element, String childElementName)
{
if (element == null)
return null;

List elements = new LinkedList();
Node node = element.getFirstChild();

if (node != null)
{
do
{
if (node.getNodeType() == Node.ELEMENT_NODE && (childElementName == null || childElementName.equals(node.getNodeName())))
{
Element childElement = (Element) node;

elements.add(childElement);
}
}
while ((node = node.getNextSibling()) != null);
}
return elements;
}

/** Return the first child Element with the given name; if name is null
* returns the first element. */
public static Element firstChildElement(Element element, String childElementName)
{
if (element == null)
return null;
// get the first element with the given name
Node node = element.getFirstChild();

if (node != null)
{
do
{
if (node.getNodeType() == Node.ELEMENT_NODE && (childElementName == null || childElementName.equals(node.getNodeName())))
{
Element childElement = (Element) node;

return childElement;
}
}
while ((node = node.getNextSibling()) != null);
}
return null;
}

/** Return the first child Element with the given name; if name is null
* returns the first element. */
public static Element firstChildElement(Element element, String childElementName, String attrName, String attrValue)
{
if (element == null)
return null;
// get the first element with the given name
Node node = element.getFirstChild();

if (node != null)
{
do
{
if (node.getNodeType() == Node.ELEMENT_NODE && (childElementName == null || childElementName.equals(node.getNodeName())))
{
Element childElement = (Element) node;

String value = childElement.getAttribute(attrName);

if (value != null && value.equals(attrValue))
{
return childElement;
}
}
}
while ((node = node.getNextSibling()) != null);
}
return null;
}

/** Return the text (node value) contained by the named child node. */
public static String childElementValue(Element element, String childElementName)
{
if (element == null)
return null;
// get the value of the first element with the given name
Element childElement = firstChildElement(element, childElementName);

return elementValue(childElement);
}

/** Return the text (node value) contained by the named child node or a default value if null. */
public static String childElementValue(Element element, String childElementName, String defaultValue)
{
if (element == null)
return defaultValue;
// get the value of the first element with the given name
Element childElement = firstChildElement(element, childElementName);
String elementValue = elementValue(childElement);

if (elementValue == null || elementValue.length() == 0)
return defaultValue;
else
return elementValue;
}

/** Return the text (node value) of the first node under this, works best if normalized. */
public static String elementValue(Element element)
{
if (element == null)
return null;
// make sure we get all the text there...
element.normalize();
Node textNode = element.getFirstChild();

if (textNode == null)
return null;

StringBuffer valueBuffer = new StringBuffer();
do
{
if (textNode.getNodeType() == Node.CDATA_SECTION_NODE || textNode.getNodeType() == Node.TEXT_NODE)
{
valueBuffer.append(textNode.getNodeValue());
}
}
while ((textNode = textNode.getNextSibling()) != null);
return valueBuffer.toString();
}

public static String checkEmpty(String string)
{
if (string != null && string.length() > 0)
return string;
else
return "";
}

public static String checkEmpty(String string1, String string2)
{
if (string1 != null && string1.length() > 0)
return string1;
else
if (string2 != null && string2.length() > 0)
return string2;
else
return "";
}

public static String checkEmpty(String string1, String string2, String string3)
{
if (string1 != null && string1.length() > 0)
return string1;
else
if (string2 != null && string2.length() > 0)
return string2;
else
if (string3 != null && string3.length() > 0)
return string3;
else
return "";
}

public static boolean checkBoolean(String str)
{
return checkBoolean(str, false);
}

public static boolean checkBoolean(String str, boolean defaultValue)
{
if (defaultValue)
{
//default to true, ie anything but false is true
return !"false".equals(str);
}
else
{
//default to false, ie anything but true is false
return "true".equals(str);
}
}

/**
* Local entity resolver to handle J2EE DTDs. With this a http connection
* to sun is not needed during deployment.
* Function boolean hadDTD() is here to avoid validation errors in
* descriptors that do not have a DOCTYPE declaration.
*/
public static class LocalResolver implements EntityResolver
{

private boolean hasDTD = false;
private EntityResolver defaultResolver;

public LocalResolver(EntityResolver defaultResolver)
{
this.defaultResolver = defaultResolver;
}

/**
* Returns DTD inputSource. If DTD was found in the dtds Map and inputSource was created
* flag hasDTD is set to true.
* @param publicId - Public ID of DTD
* @param systemId - System ID of DTD
* @return InputSource of DTD
*/
public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException
{
hasDTD = false;
String dtd = UtilProperties.getSplitPropertyValue(UtilURL.fromResource("localdtds.properties"), publicId);

if (Debug.verboseOn())
Debug.logVerbose("[UtilXml.LocalResolver.resolveEntity] resolving DTD with publicId [" + publicId + "], systemId [" + systemId + "] and the dtd file is [" + dtd + "]", module);
if (dtd != null && dtd.length() > 0)
{
try
{
URL dtdURL = UtilURL.fromResource(dtd);
InputStream dtdStream = dtdURL.openStream();
InputSource inputSource = new InputSource(dtdStream);

inputSource.setPublicId(publicId);
hasDTD = true;
if (Debug.verboseOn())
Debug.logVerbose("[UtilXml.LocalResolver.resolveEntity] got LOCAL DTD input source with publicId [" + publicId + "] and the dtd file is [" + dtd + "]", module);
return inputSource;
}
catch (Exception e)
{
Debug.logWarning(e, module);
}
}
if (Debug.verboseOn())
Debug.logVerbose(
"[UtilXml.LocalResolver.resolveEntity] local resolve failed for DTD with publicId [" + publicId + "] and the dtd file is [" + dtd + "], trying defaultResolver",
module);
return defaultResolver.resolveEntity(publicId, systemId);
}

/**
* Returns the boolean value to inform id DTD was found in the XML file or not
* @return boolean - true if DTD was found in XML
*/
public boolean hasDTD()
{
return hasDTD;
}
}

/** Local error handler for entity resolver to DocumentBuilder parser.
* Error is printed to output just if DTD was detected in the XML file.
*/
public static class LocalErrorHandler implements ErrorHandler
{

private String docDescription;
private LocalResolver localResolver;

public LocalErrorHandler(String docDescription, LocalResolver localResolver)
{
this.docDescription = docDescription;
this.localResolver = localResolver;
}

public void error(SAXParseException exception)
{
if (localResolver.hasDTD())
{
Debug.logError("XmlFileLoader: File " + docDescription + " process error. Line: " + String.valueOf(exception.getLineNumber()) + ". Error message: " + exception.getMessage(), module);
}
}

public void fatalError(SAXParseException exception)
{
if (localResolver.hasDTD())
{
Debug.logError(
"XmlFileLoader: File " + docDescription + " process fatal error. Line: " + String.valueOf(exception.getLineNumber()) + ". Error message: " + exception.getMessage(),
module);
}
}

public void warning(SAXParseException exception)
{
if (localResolver.hasDTD())
{
Debug.logError("XmlFileLoader: File " + docDescription + " process warning. Line: " + String.valueOf(exception.getLineNumber()) + ". Error message: " + exception.getMessage(), module);
}
}
}
}