关于XML的CRUD

使用dom4j：

http://www.dom4j.org/

 

参考文章：

http://www.ibm.com/developerworks/cn/xml/x-dom4j.html

 

 

下载jar包：

dom4j-1.6.1.jar  

dom4j-full.jar

 

注意：如果不加dom4j-full.jar这个包，有可能报错

 

 

接口：

package xmlService;import java.util.Hashtable;import xmlBean.User;public interface UserService {public Hashtable<?, ?> getAllUser();public User getUserById(String id);public boolean addUser(User user);public boolean updateUser(User user);public boolean deleteUser(User user);}

 

 

实现类：

package xmlAction;import java.io.File;import java.io.FileWriter;import java.io.IOException;import java.util.Hashtable;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.SAXReader;import org.dom4j.io.XMLWriter;import xmlBean.User;import xmlService.UserService;public class UserAction implements UserService {Document document;String xmlFilePos;public UserAction(String xmlFilePos) {this.xmlFilePos = xmlFilePos;if ((new File(this.xmlFilePos)).exists() == false) {document = DocumentHelper.createDocument();Element usersElm = document.addElement("users");Element userElm = usersElm.addElement("user");userElm.addAttribute("id", "");userElm.addElement("name");userElm.addElement("age");XMLWriter writer;try {writer = new XMLWriter(new FileWriter(this.xmlFilePos));writer.write(document);writer.close();} catch (IOException e) {e.printStackTrace();}} else {SAXReader reader = new SAXReader();try {document = reader.read(new File(this.xmlFilePos));} catch (DocumentException e) {e.printStackTrace();}}}public boolean addUser(User user) {String s = "";Element root = document.getRootElement();List<?> nodes = root.elements("user");for (Iterator<?> it = nodes.iterator(); it.hasNext();) {Element elm = (Element) it.next();if (elm.attributeValue("id").equals("")) {s = user.getId();elm.setAttributeValue("id", s);// elm.element("id").attribute(s);elm.element("name").setText(user.getName());elm.element("age").setText(String.valueOf(user.getAge()));break;}}if (s.equals("") && s.length() == 0) {Element rootElm = document.getRootElement();Element userElm = rootElm.addElement("user");userElm.addAttribute("id", user.getId());Element nameElm = userElm.addElement("name");nameElm.setText(user.getName());Element ageElm = userElm.addElement("age");ageElm.setText(String.valueOf(user.getAge()));}try {XMLWriter writer = new XMLWriter(new FileWriter(this.xmlFilePos));writer.write(document);writer.close();} catch (IOException e) {e.printStackTrace();return false;}return true;}public boolean deleteUser(User user) {Element root = document.getRootElement();List<?> nodes = root.elements("user");String s = "";for (Iterator<?> it = nodes.iterator(); it.hasNext();) {Element elm = (Element) it.next();if (elm.element("id").equals(user.getId())) {s = user.getId();root.remove(elm);}}if (s.equals("") || s.length() == 0) {return false;}return true;}public Hashtable<String, Element> getAllUser() {Hashtable<String, Element> ht = null;List<?> nodes = document.getRootElement().elements("user");for (Iterator<?> it = nodes.iterator(); it.hasNext();) {Element element = (Element) it.next();User user = new User();user.setId(element.elementText("id"));user.setName(element.elementText("name"));user.setAge(Integer.parseInt(element.elementText("age")));ht.put(element.elementText("id"), element);System.out.println(element.getText());}return ht;}public User getUserById(String id) {Element root = document.getRootElement();List<?> nodes = root.elements("user");for (Iterator<?> it = nodes.iterator(); it.hasNext();) {Element elm = (Element) it.next();if (elm.element("id").equals(id)) {User user = new User();user.setId(id);user.setName(elm.elementText("name"));user.setAge(Integer.parseInt(elm.elementText("age")));return user;}}return null;}public boolean updateUser(User user) {Element root = document.getRootElement();List<?> nodes = root.elements("user");String s = "";for (Iterator<?> it = nodes.iterator(); it.hasNext();) {Element elm = (Element) it.next();if (elm.element("id").equals(user.getId())) {s = user.getId();elm.element("name").setText(user.getName());elm.element("age").setText(String.valueOf(user.getAge()));break;}}if (s.equals("") || s.length() == 0) {return false;}return true;}}