关系管理系统:JdbcUtils工具类代码

package cn.itcast.utils;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class JdbcUtils {
    
    private static String url = null;
    private static String username = null;
    private static String password = null;
    
    static{
        try{
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties");
            Properties prop = new Properties();
            prop.load(in);
            
            String driver = prop.getProperty("driver");
            url = prop.getProperty("url");
            username = prop.getProperty("username");
            password = prop.getProperty("password");
            
            Class.forName(driver);
            
        }catch (Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static Connection getConnection() throws SQLException{
        
        return DriverManager.getConnection(url, username, password);
    }
    
    public static void release(Connection conn,Statement st,ResultSet rs){
        
        
        if(rs!=null){
            try{
                rs.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
            rs = null;

        }
        if(st!=null){
            try{
                st.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
            
        }
        
        if(conn!=null){
            try{
                conn.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
            
        }
    }
    
}

db.properties配置文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/customer
username=root
password=root

#Oracle 数据库驱动
#driver=oracle.jdbc.driver.OracleDriver
#url=jdbc:oracle:thin:@localhost:1521:orcl
#username=system
#password=itcast