JavaBean使用MySQL

package com.zzhoujsp_jbean.javabean;

 

public class UserBean

{

    public boolean valid(String username,String password)

    {

       boolean isValid=false;

       DBAccess db=new DBAccess();

      

       if(db.createConn())

       {

           String sql="select * from user where username='"+username+"' and password='"+password+"'";

           db.query(sql);

          

           if(db.next())

           {

              isValid=true;

           }

           db.closeRs();

           db.closeStm();

           db.closeConn();

       }

       return isValid;

    }

    public boolean isExist(String username)

    {

       boolean isExist=false;

       DBAccess db=new DBAccess();

       if(db.createConn())

       {

           String sql="select * from user where username='"+username+"'";

           db.query(sql);

          

           if(db.next())

           {

              isExist=true;

           }

           db.closeRs();

           db.closeStm();

           db.closeConn();

       }

       return isExist;

    }

    public void add(String username,String password,String email)

    {

       DBAccess db=new DBAccess();

       if(db.createConn())

       {

           String sql="insert into user(username,password,email) values('"+username+"','"+password+"','"+email+"')";

           db.update(sql);

           db.closeStm();

           db.closeConn();

       }

    }

}