import java.sql.Connection;    
import java.sql.DriverManager;    
import java.util.Properties;    

//java 连接MySql的三种方法
public class ConnectionUtil {  
  
        //第一种方法    
        public Connection getConnection(){    
                Connection conn = null;    
                try {    
                        //Class.forName加载驱动    
                        Class.forName("com.mysql.jdbc.Driver");    
                        //DriverManager获得连接    
                        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc_db","root","mysqladmin");    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }   

 
        //第二种方法    
        public Connection getConnection(String driver,String url,String user,String password){    
                Connection conn = null;    
                try {    
                        //Class.forName加载驱动    
                        Class.forName(driver);    
                        //DriverManager获得连接    
                        conn = DriverManager.getConnection(url,user,password);    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }    


        //第三种方法    
        public Connection openConnection(){    
                String driver = "";    
                String url = "";    
                String user = "";    
                String password = "";    
                Properties prop = new Properties();    
                Connection conn = null;    
                try {    
                        //加载属性文件    
                        prop.load(this.getClass().getClassLoader().getResourceAsStream("DBConfig.properties"));    
                        driver = prop.getProperty("driver");    
                        url = prop.getProperty("url");    
                        user = prop.getProperty("user");    
                        password = prop.getProperty("password");    
                        //Class.forName加载驱动    
                        Class.forName(driver);    
                        //DriverManager获得连接    
                        conn = DriverManager.getConnection(url,user,password);    
                        return conn;    
                } catch (Exception e) {    
                        e.printStackTrace();    
                }    
                return null;    
        }    

}