JDBC连接数据库工具类

package org.dtt.all;


import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
/**
 * 连接管理工具类
 * @author jiandandia
 *
 */
public class DBUtil {
//加载驱动
private static String driverClass=null;
private static String url=null;
private static String username=null;
private static String password=null;
static{
//加载底层的连接信息
Properties prop=new Properties();
InputStream is=DBUtil.class.getClassLoader()
.getResourceAsStream("db.properties");
try {
prop.load(is);
driverClass=prop.getProperty("driverClass");
url=prop.getProperty("url");
username=prop.getProperty("username");
password=prop.getProperty("password");
//加载驱动
Class.forName(driverClass);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
//获取连接的方法
public static Connection openConnection() throws SQLException{

return DriverManager.getConnection(url,username,password);
}
//释放资源
public static void close(Connection conn){
if(conn!=null){
try{
conn.close();
}catch(Exception e){
e.printStackTrace();
System.out.println("释放资源失败");
}
}
}
/**
* 测试数据库连接
* @param args
*/
public static void main(String[] args){
try {
System.out.println(openConnection());
} catch (SQLException e) {

e.printStackTrace();
}

}
}