DOM4J对XML文档的读写增删改等操作

用DOM4J对XML文档的读写增删改等操作，是我自己的练习题，没有整理和注释，只做以后查看之用。主要方法在构造函数中做了简单说明，涉及到的 XML、XSD、DTD文档不再写入。

package xml.dom4j.wkjava;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class Test {
	
	Document doc = null;

  public Test() throws DocumentException, IOException, SAXException {
      Document doc = loadXML("class.xml"); //载入XML文档
     System.out.println(doc.asXML());
		
      printDoc(doc); //打印XML文档
		
     storeDoc(doc,"new.xml"); //把XML文档存入硬盘
				
     doc = valideDoc("class.xml");  //校验dtd XML文档
     printDoc(doc);
		
     doc = validateDocBySxd("classSchema.xml"); //校验Schema文档
     printDoc(doc);
		
     String url = getClass().getResource("/xml/dom4j/wkjava/class.xsd").toString();
     doc = validateDocBySxd("classSchema.xml",url); //校验Schema文档（俩参数）
     printDoc(doc);
		
     doc = createDoc(); //创建Schema文档
    storeDoc(doc,"root.xml");
		
     doc = validateDocBySxd("classSchema.xml");
     updateZip(doc,"102202"); //在文档中修改原属
    printDoc(doc);
		
     doc = validateDocBySxd("classSchema.xml");
     printNames(doc);  //打印文档中所有学生名字
    System.out.println(getStudentCount(doc));
  }
	public static void main(String[] args) {
		try {
			new Test();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (DocumentException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		}
	}

	public Document loadXML(String xmlfile)
	    throws FileNotFoundException, DocumentException{
	    SAXReader reader = new SAXReader();
	    doc = reader.read(new FileInputStream(xmlfile));
	    return doc;
	}
	
    public void printDoc(Document doc) throws IOException {
    	Writer out = new OutputStreamWriter(System.out,"gb2312");
	    OutputFormat format = OutputFormat.createPrettyPrint();
	    XMLWriter writer = new XMLWriter(out, format);
	    writer.write(this.doc);
	    out.flush();
	 }
    
    public void storeDoc(Document doc,String filename) throws IOException {
    	Writer out = new OutputStreamWriter(new FileOutputStream(filename),"utf-8");
	    OutputFormat format = OutputFormat.createPrettyPrint();
	    XMLWriter writer = new XMLWriter(out, format);
	    writer.write(this.doc);
	    printDoc(doc);
	    out.close();
	 }

    public Document valideDoc(String xmlfile) throws DocumentException, IOException{
    	EntityResolver resolver = new EntityResolver(){
			public InputSource resolveEntity(String publicId, String systemId)
			    throws SAXException, IOException {
				if(publicId.equals("//class from weiking")){
					InputStream in = new FileInputStream("class.dtd");
					return new InputSource(in);
				}
				return null;
			}   		
    	};
    	SAXReader reader = new SAXReader(true);
    	reader.setEntityResolver(resolver);
    	Document doc = reader.read(new FileInputStream(xmlfile));
    	return doc;
    }
    
    public Document validateDocBySxd(String xmlfile) throws SAXException, DocumentException, IOException{
    	SAXReader reader = new SAXReader(true);
    	reader.setFeature("http://apache.org/xml/features/validation/schema",true);
    	Document doc = reader.read(new FileInputStream(xmlfile));
    	return doc;
    }
    
    public Document validateDocBySxd(String xmlfile,String SchemaUrl)
        throws SAXException, FileNotFoundException, DocumentException{
    	SAXReader reader = new SAXReader(true);
    	reader.setFeature("http://xml.org/sax/features/validation", true);
		reader.setFeature("http://apache.org/xml/features/validation/schema",true);
		reader.setFeature("http://apache.org/xml/features/validation/schema-full-checking",true);
		reader.setProperty("http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",SchemaUrl);
    	Document doc = reader.read(new FileInputStream(xmlfile));
    	return doc;
    }
    
    public Document createDoc() {
        Document doc = DocumentHelper.createDocument();
        Element root = doc.addElement( "root" );

        Element author2 = root.addElement( "author" )
          .addAttribute( "name", "Toby" )
          .addAttribute( "location", "Germany" )
          .addText( "Tobias Rademacher" );

        Element author1 = root.addElement( "author" )
          .addAttribute( "name", "James" )
          .addAttribute( "location", "UK" )
          .addText( "James Strachan" );

        return doc;
      }

    public void updateZip(Document doc,String zip){
    	String xpath = "/Class/Teacher/zip";
    	Element e = (Element)doc.selectSingleNode(xpath);
    	e.setText(zip);
    }
    
    public void printNames(Document doc){
    	String xpath = "/Class/Students/Student/name";
    	List list = doc.selectNodes(xpath);
    	for(Iterator i = list.iterator(); i.hasNext();){
    		Element e = (Element)i.next();
    		System.out.println(e.element("last").getText() + e.valueOf("first"));
    	}
    }
    
    public int getStudentCount(Document doc){
    	int count = 0;
    	String xpath ="count(/Class/Students/Student)";
    	count = doc.numberValueOf(xpath).intValue();
//    	String value = doc.valueOf(xpath);
//    	count = Integer.parseInt(value);
    	return count;