DOM4J對XML文檔的讀寫增刪改等

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"); // 載入XML文檔
    System.out.println(doc.asXML());
    printDoc(doc); // 打印XML文檔
    storeDoc(doc, "new.xml"); // 把XML文檔存入硬盤
    doc = valideDoc("class.xml"); // 校驗dtd XML文檔
    printDoc(doc);
    doc = validateDocBySxd("classSchema.xml"); // 校驗Schema文檔
    printDoc(doc);
    String url = getClass().getResource("/xml/dom4j/wkjava/class.xsd").toString();
    doc = validateDocBySxd("classSchema.xml", url); // 校驗Schema文檔（倆參數）
    printDoc(doc);
    doc = createDoc(); // 創建Schema文檔
    storeDoc(doc, "root.xml");
    doc = validateDocBySxd("classSchema.xml");
    updateZip(doc, "102202"); // 在文檔中修改原屬
    printDoc(doc);
    doc = validateDocBySxd("classSchema.xml");
    printNames(doc); // 打印文檔中所有學生名字
    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;
  }
}