privatestaticString url = "jdbc:mysql://127.0.0.1:3306/students";   

privatestaticString user = "root";  

privatestaticString password = null;

privatestaticjava.sql.Connection con = null;    

static{      

    try{         

        Class.forName("com.mysql.jdbc.Driver");

        //为什么会在上一句报错java.lang.ClassNotFoundException: com.mysql.jdbc.Driver   

    } catch(ClassNotFoundException e) {           

        e.printStackTrace();       

    }      

    try{         

        con = DriverManager.getConnection(url, user, password);    

    } catch(SQLException e) {         

        e.printStackTrace();       

    }  

}