dom4j对xml的增删改查

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 MyTest {   
  Document doc = null;   
  
  public MyTest() 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 MyTest();   
    } 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;   
  }   
}  希望对除学者 有帮助