handlelogin.java

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package myservlet.control;
import mybean.data.*;
import java.sql.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HandleLogin extends HttpServlet
{   public void init(ServletConfig config) throws ServletException
    { super.init(config);
      try {  Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
          }
       catch(Exception e){} 
    }
   public String handleString(String s)
   {   try{ byte bb[]=s.getBytes("iso-8859-1");
            s=new String(bb);
          }
       catch(Exception ee){} 
       return s;  
   }
   public  void  doPost(HttpServletRequest request,HttpServletResponse response) 
                        throws ServletException,IOException
    {   Connection con; 
        PreparedStatement sql; 
        Login loginBean=null;
        String backNews="";
        HttpSession session=request.getSession(true);
        try{  loginBean=(Login)session.getAttribute("login");
              if(loginBean==null)
              { loginBean=new Login();  
                session.setAttribute("login",loginBean);
              }
           }
        catch(Exception ee)
          {  loginBean=new Login();  
             session.setAttribute("login",loginBean);
          }
        String logname=request.getParameter("logname").trim(),
        password=request.getParameter("password").trim();
        boolean ok=loginBean.getSuccess();
        logname=handleString(logname);
        password=handleString(password);
        if(ok==true&&logname.equals(loginBean.getLogname()))
        {  backNews=logname+"已经登录了";
           loginBean.setBackNews(backNews);
        }
        else
        {  String uri="jdbc:sqlserver://192.168.1.222:1433;DatabaseName=Friend";
           boolean boo=(logname.length()>0)&&(password.length()>0);  
           try{ con=DriverManager.getConnection(uri,"sa","sa");
                String condition="select * from member where logname =? and password =?";
                sql=con.prepareStatement(condition);  
                if(boo)
                { sql.setString(1,logname);
                  sql.setString(2,password); 
                  ResultSet rs=sql.executeQuery();
                  boolean m=rs.next();
                  if(m==true)
                  {  backNews="登录成功";
                     loginBean.setBackNews(backNews);
                     loginBean.setSuccess(true);
                     loginBean.setLogname(logname);
                  }
                 else
                  {  backNews="您输入的用户名不存在，或密码不般配";
                     loginBean.setBackNews(backNews); 
                     loginBean.setSuccess(false); 
                     loginBean.setLogname(logname);
                     loginBean.setPassword(password);
                  }
                }
                else
                { backNews="您输入的用户名不存在，或密码不般配";
                  loginBean.setBackNews(backNews); 
                  loginBean.setSuccess(false); 
                  loginBean.setLogname(logname);
                  loginBean.setPassword(password);
                }
                con.close();
              }
           catch(SQLException exp)
             {  backNews=""+exp;
                loginBean.setBackNews(backNews); 
                loginBean.setSuccess(false); 
             }
        }
       RequestDispatcher dispatcher=request.getRequestDispatcher("showLoginMess.jsp");
       dispatcher.forward(request, response);
    }
   public  void  doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException
    {   doPost(request,response);
    }
}