login_confirm.java

采用基于B/S结构进行开发学生管理信息系统,本系统采用Servlet+Jsp+JavaBean+MySQL 的设计方式

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import myBeans.SQLBean;

public class login_confirm extends HttpServlet{
 
 public void doPost(HttpServletRequest req, HttpServletResponse res)
    throws ServletException, IOException {	
        
   String message=null; 
   String id=null;
   id=req.getParameter("id").toString();
   HttpSession session=req.getSession(true);
   session.setAttribute("id",String.valueOf(id));
   
   String password=null;
   password=req.getParameter("password").toString();

   String kind =null;
   kind=req.getParameter("kind").toString();

   String temp=getPassword(req,res,id,kind);
   if( password.equals(temp))
   goo(req,res,kind);
   else {
   message="用户名或密码有误！";
   doError(req,res,message);
 	}
 	} 
  
public void goo(HttpServletRequest req, HttpServletResponse res,String kind)
throws ServletException,IOException
{

	if(kind.equals("student")) {	
	RequestDispatcher rd = getServletContext().getRequestDispatcher("/student.jsp");
    rd.forward(req, res);}
    if(kind.equals("teacher")){
    	RequestDispatcher rd = getServletContext().getRequestDispatcher("/teacher.jsp");
    rd.forward(req, res);}
    if(kind.equals("studba")){
    	RequestDispatcher rd = getServletContext().getRequestDispatcher("/admin.jsp");
    rd.forward(req, res);}
	}
	

  
     
  public String getPassword(HttpServletRequest req, HttpServletResponse res,
                        String id,String kind)
                        throws ServletException, IOException {
 /*    try{
        Class.forName("com.mysql.jdbc.Driver");
      }catch(ClassNotFoundException e){
      System.err.println("执行查询有错误:"+e.getMessage() ); 
      System.out.print("执行查询有错误:"+e.getMessage()); //输出到客户端
    }
    Connection conn = null;
    Statement st = null;
    try{
       conn = DriverManager.getConnection("jdbc:mysql://localhost/studb","root","125125");
       st = conn.createStatement();
      }catch(SQLException ex){
      	System.err.println("执行查询有错误:"+ex.getMessage() ); 
        System.out.print("执行查询有错误:"+ex.getMessage()); //输出到客户端
      }
      String sql="select PASSWORD from "+kind+" where ID='"+id+"'";
      String pw=""; 
      try{
        ResultSet rs = st.executeQuery(sql);
        if(rs.next())
           pw = rs.getString("PASSWORD");
          }catch(Exception ec){
        System.out.print(ec.toString());
          }*/    
   SQLBean db= new SQLBean();        	
   String pw="";                     	                     	
   String sql="select PASSWORD from "+kind+" where ID='"+id+"'";
   try{
   ResultSet rs=db.executeQuery(sql);	
   if(rs.next()){
     pw= rs.getString("PASSWORD");
   	}
   	} 
   	catch(Exception e)
    { System.out.print(e.toString());}   	
    return pw; 
   }
     
     	
      
     public void doError(HttpServletRequest req,
                      HttpServletResponse res,
                      String str)
                      throws ServletException, IOException {

    req.setAttribute("problem", str);
    RequestDispatcher rd = getServletContext().getRequestDispatcher("/errorpage.jsp");
    rd.forward(req, res);
  }
  
  
  public void doGet(HttpServletRequest req, HttpServletResponse res)
    throws ServletException, IOException {
    	 String action =  req.getParameter("action");
      if ("logout".equalsIgnoreCase(action)) {
      HttpSession session=req.getSession(true);
        session.invalidate();
        RequestDispatcher rd = getServletContext().getRequestDispatcher("/login.jsp");
        rd.forward(req, res);
    } }
  
}