java通过配置文件jdbc.properties链接Oracle数据库工具类

package resources;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.SQLException;
import java.util.Properties;

public class DbUtil {  
    public static Connection getConnection(){  
        String driverClass = null;  
        String jdbcUrl = null;  
        String user = null;  
        String password = null;  

        //读取类路径下的 jdbc.properties 文件，我的配置文件放在src包下
        InputStream in = DbUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");  
        Properties properties = new Properties();  
        try {
            properties.load(in);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  
        driverClass = properties.getProperty("driver");  
        jdbcUrl = properties.getProperty("jdbcUrl");  
        user = properties.getProperty("username");  
        password = properties.getProperty("password");  

        Driver driver = null;
        try {
            driver = (Driver) Class.forName(driverClass).newInstance();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  

        Properties info = new Properties();
        info.put("user", user);
        info.put("password", password);  

        //通过 Driver 的 connect 方法获取数据库连接.   
        Connection connection = null;
        try {
            connection = driver.connect(jdbcUrl, info);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  
        System.out.println("----The database is connected----");
        return connection;  
    } 
}


jdbc.properties内容如下：
driver=oracle.jdbc.driver.OracleDriver
#jdbcUrl=jdbc\:oracle\:thin\:@10.91.4.102\:1521\:orcl
jdbcUrl=jdbc\:oracle\:thin\:@127.0.0.1\:1521\:orcl
username=cp2
password=cp2test


//调用方法
public static void main(String[] args) {
        String id = "111111";
        String gread = "3";
        List sList = new ArrayList();
        Connection con = DbUtilCR.getConnection();
        PreparedStatement pre = null;
        ResultSet result = null;
        String sql = "select s.name,s.age from student s where s.id=? and s.gread=?";
        try {
            pre = con.prepareStatement(sql);
            pre.setString(1, id);//传参数学号
            pre.setString(2, gread);//传参数年级
            result = pre.executeQuery();
            System.out.println("执行SQL为：["+sql+"]");
            System.out.println("参数为：["+id+","+gread+"]");
            while (result.next()){
                Student st = new Student();
                st.setName(result.getString("name"));//与查询出的字段或者别名保持一致
                st.setAge(result.getString("age"));
                sList.add(st);
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  
        for (int i = 0;i
            System.out.println("姓名："+sList.get(i).getName()+"\t年龄："+sList.get(i).getAge());

        }
    }