loginservlet.java

我自己写的javabean+jsp+servlet

package com.gke;

import com.gke.DBUtil;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.servlet.RequestDispatcher;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginServlet extends HttpServlet implements Servlet {
	public void doPost(HttpServletRequest request,HttpServletResponse response){
		response.setContentType("text/html");
		String result = "";
		String sUserName=request.getParameter("txtUserName");
		String sPasswd = request.getParameter("txtPassword");
		HttpSession session = request.getSession();
		
		if(sUserName==""||sUserName==null||sUserName.length()>20){
			result = "请输入用户名（不超过20个字符）";
			request.setAttribute("ErrorUserName", result);
	
			try {
				response.sendRedirect("login.html");
			} catch (IOException e) {
				e.printStackTrace();
			}
		}else{
		
			Connection conn =null;
			Statement stmt = null;
			ResultSet rs = null;
		
			try {
				conn = DBUtil.getConnection();
				stmt = conn.createStatement();
			
				String sql = "select * from userinfo where username ='"+sUserName+"'and password ='"+sPasswd+"' ";
				rs = stmt.executeQuery(sql);
		
				String obj = request.getParameter("validate");
				String obj1= (String)session.getAttribute("myrand");
	 	
				if(rs.next()&&obj1.equals(obj)){
					request.getSession().setAttribute("UserName", sUserName);
					response.sendRedirect("login_success.jsp");
				}else{
					response.sendRedirect("login_failure.jsp");
				}
				if(rs!=null){
					rs.close();
				}
				if(stmt!=null){
					stmt.close();
				}
				if(conn!=null){
					conn.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
			}
		}
	}
	public void doGot(HttpServletRequest request,HttpServletResponse response){
		doPost(request,response);
	}
}