用XMLJdbcConfigReader简单读取XML配置文件
步骤1、编写xml配置文件；2、编写实体类JdbcConfig；3、在编写XMLJdbcConfigReader来读取xml配置文件。
步骤1、编写xml配置文件
<?xml version="1.0" encoding="utf-8"  ?>
<!--
数据库相关信息: 1、驱动；2、url；3、user；4、password
-->
<config>
<db-info>
<driver-name>com.mysql.jdbc.Driver</driver-name>
<url>jdbc:mysql://localhost:3306/test?autoReconnect=true&amp;useUnicode=true&amp;characterEncoding=UTF-8</url>
<user-name>root</user-name>
<password>root</password>
</db-info>
</config>

步骤2、编写实体类JdbcConfig

package net.etwo.model;

public class JdbcConfig {

/**
* 数据库相关信息
* 1、驱动；2、url；3、user；4、password
*/
private String driverName;

private String url;

private String user;

private String password;

public String getDriverName() {
return driverName;
}

public void setDriverName(String driverName) {
this.driverName = driverName;
}

public String getUrl() {
return url;
}

public void setUrl(String url) {
this.url = url;
}

public String getUser() {
return user;
}

public void setUser(String user) {
this.user = user;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

@Override
public String toString() {
// TODO Auto-generated method stub
return "driverName:" + this.driverName + "\nurl:" + this.url + "\nuser:" + this.user + "\npassword:" + this.password;
}

}

步骤3、在编写XMLJdbcConfigReader来读取xml配置文件

package net.etwo.util;

import java.io.InputStream;

import net.etwo.model.JdbcConfig;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class XMLJdbcConfigReader {

/**
* 采用单例模式解析XML
*/

private static XMLJdbcConfigReader instance;

private static JdbcConfig jdbcConfig = new JdbcConfig();

private XMLJdbcConfigReader() {

//解析XML
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("sys-config.xml");

SAXReader reader = new SAXReader();

try {
Document doc = reader.read(is);
Element eleDriverName = (Element)doc.selectObject("/config/db-info/driver-name");
Element eleUrl = (Element)doc.selectObject("/config/db-info/url");
Element eleUser = (Element)doc.selectObject("/config/db-info/user-name");
Element elePassword = (Element)doc.selectObject("/config/db-info/password");

String driverName = eleDriverName.getStringValue();
String url = eleUrl.getStringValue();
String user = eleUser.getStringValue();
String password = elePassword.getStringValue();

jdbcConfig.setDriverName(driverName);
jdbcConfig.setUrl(url);
jdbcConfig.setUser(user);
jdbcConfig.setPassword(password);
} catch (DocumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public static synchronized XMLJdbcConfigReader getInstance() {
if(instance ==null) {
instance = new XMLJdbcConfigReader();
}
return instance;
}

public JdbcConfig getJdbcConfig() {
return jdbcConfig;
}

public static void main(String[] args) {
new XMLJdbcConfigReader().getInstance();
System.out.println(jdbcConfig);
}
}