DOM4J对XML文档的读写增删改等

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;