现在有一个名为global-configure.xml的配置文件,内容如下
<?xml version="1.0" encoding="UTF-8"?>
<sys-configure>
 <jdbc-info>
  <driver-class-name>oracle.jdbc.driver.OracleDriver</driver-class-name>
  <url>jdbc:oracle:thin:@127.0.0.1:1521:yqs</url>
  <user-name>root</user-name>
  <password>yqsshr</password>
 </jdbc-info>
 
 <beans>
  <bean id="com.yqs.drp.basedata.dao.ItemDao" class="com.yqs.bbs.basedata.dao.ItemDao.ClassName" />
  <bean id="com.yqs.bbs.basedata.dao.FlowCardDao" class="com.yqs.bbs.basedata.dao.FlowCardDao.ClassName" />
  <!-- 可把所有的Dao配置进来 -->
 </beans>
</sys-configure>
现在要用Jdom读取其中的driver-class-name、url、user-name、password四个元素的内容，并将它放到JdbcInfo.java这个JavaBean中。
 
首先，先建立一个web工程，将Jdom（需要自己下载）文件夹下的lib下的所有jar包以及build下的jdom.jar包拷贝到WEB-INF下的lib文件夹下。
 
建立GlobalConfigure.java文件，内容如下：
import java.io.IOException;
import org.jdom.Document;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.Element;
import org.jdom.xpath.*;
public class GlobalConfigure {
//采用单例模式,因为只需读取配置文件一次即可
 private static GlobalConfigure instance = new GlobalConfigure();
 
 private static final String CONFIG_FILE_NAME = "gobal-configure.xml";
 
 private Element rootElt;
 
 private JdbcInfo jdbcInfo = new JdbcInfo(); //JavaBean对象
 
 private GlobalConfigure() {
  SAXBuilder sb = new SAXBuilder();
  try {
   Document doc = sb.build(Thread.currentThread().getContextClassLoader().getResourceAsStream(CONFIG_FILE_NAME));  //读取文件
   this.rootElt  = doc.getRootElement();  //取得根文件
   initJdbcInfo();
  } catch (JDOMException e) {
   System.out.println("jdom error");
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   System.out.println("io error");
   e.printStackTrace();
  }
 }
 
 private static GlobalConfigure getInstance() {
  return instance;
 }
 
 private void initJdbcInfo() {
  try {
//取得driver-class-name、url、user-name、password四个元素的内容
   Element driverClassNameElt = (Element)XPath.selectSingleNode(rootElt, "//sys-configure/jdbc-info/driver-class-name");
   Element urlElt = (Element)XPath.selectSingleNode(rootElt, "//sys-configure/jdbc-info/url");
   Element userNameElt = (Element)XPath.selectSingleNode(rootElt, "//sys-configure/jdbc-info/user-name");
   Element passwordElt = (Element)XPath.selectSingleNode(rootElt, "//sys-configure/jdbc-info/password");
 //将内容放到JavaBean
   jdbcInfo.setDriverClassName(driverClassNameElt.getText());
   jdbcInfo.setUrl(urlElt.getText());
   jdbcInfo.setPassword(passwordElt.getText());
   jdbcInfo.setUserName(userNameElt.getText());
//System.out.println(driverClassNameElt.getText());
//System.out.println(urlElt.getText());
  } catch (JDOMException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 
 public static void main(String[] args) {
  System.out.println(GlobalConfigure.getInstance()); //打印测试
 }
 public JdbcInfo getJdbcInfo() {
  return jdbcInfo;
 }
 
 public String toString() {
  return "driverClassName:" + jdbcInfo.getDriverClassName() +
    "\nURL:" + jdbcInfo.getUrl() +
    "\nusername:" + jdbcInfo.getUserName() +
    "\npassword:" + jdbcInfo.getPassword();
 }
}
JdbcInfo代码如下：

public class JdbcInfo {
 
 private String driverClassName;
 private String url;
 private String userName;
 private String password;
 
 public String getDriverClassName() {
  return driverClassName;
 }
 public void setDriverClassName(String driverClassName) {
  this.driverClassName = driverClassName;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 }
 public String getUrl() {
  return url;
 }
 public void setUrl(String url) {
  this.url = url;
 }
 public String getUserName() {
  return userName;
 }
 public void setUserName(String userName) {
  this.userName = userName;
 }
}

程序运行结果如下：
driverClassName:oracle.jdbc.driver.OracleDriver
URL:jdbc:oracle:thin:@127.0.0.1:1521:yqs
username:root
password:yqsshr