JSP SQL数据链接类调用问题
我写了个数据库的链接类
package   db;
import   java.sql.*;

public   class   ConnDB  
{
public   Connection   conn=null;
public   Statement   st=null;
public   String   bd_Drive= "com.microsoft.jdbc.sqlserver.SQLServerDriver ";


public   Connection   mygetConn()   throws   Exception{
      Class.forName(bd_Drive);
      String   url= "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db ";  
      String   user= "sa ";  
      String   pwd= " ";          
      conn=DriverManager.getConnection(url,user,pwd);
      st=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
      return   conn;
}

public   void   getConn()throws   Exception
{
      Class.forName(bd_Drive);
      String   url= "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db ";  
      String   user= "sa ";  
      String   pwd= " ";          
      conn=DriverManager.getConnection(url,user,pwd);

}

public   ResultSet   getRs(String   sql)throws   Exception
{
      st=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
      ResultSet   rs=st.executeQuery(sql);
      return   rs;
}

public   void   getUpdate(String   sql)throws   Exception
{
      st=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
      st.executeUpdate(sql);
}

public   void   closeConn()   throws   Exception
{
      if(st!=null)
        st.close();
      st=null;

      if(conn!=null)
            conn.close();
      conn=null;
}


}


文件调用:

package   com;
import   java.sql.*;

import   db.*;

import   db.ConnDB;
public   class   newManage
{
ConnDB   con=   new   ConnDB();

private   String   userid,password,qy,username,bm,job,type;

public   void   setUserid(String   u){userid=u;}
public   String   getUserid(){return   userid;}

public   void   setPassword(String   p){password=p;}
public   String   getPassword(){return   password;}

public   void   setQy(String   q){qy=q;}
public   String   getQy(){return   qy;}

public   void   setUsername(String   n){username=n;}
public   String   getUsername(){return   username;}

public   void   setBm(String   b){bm=b;}
public   String   getBm(){return   bm;}

public   void   setJob(String   j){job=j;}
public   String   getJob(){return   job;}

public   void   setType(String   t){typ