jsp+servlet实现注册登录，不用数据库
1、创建工程
2、创建package com.demo1.java包
3、user类
package com.demo1.java; 
import java.util.HashMap; 
import java.util.Map; 
public class User { 
private Map<String,String> userMap = new HashMap<String, String>(); 
private static User user = null; 
private User(){ 
userMap.put("韩春", "123456##***************"); 
} 
public static User getInstance(){ 
if(user == null){ 
user = new User(); 
} 
return user; 
} 
public Map<String, String>getUserMap(){ 
return userMap; 
} 
} 
江苏省教育考试院
4、创建package com.demo1.servlet;包，以下均创建servlet:
package com.demo1.servlet; 
import java.io.IOException; 
import java.io.PrintWriter; 
import java.util.List; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
public class ErrorServlet extends HttpServlet { 
private static final long serialVersionUID = 1l;                     
public void doPost(HttpServletRequest req, HttpServletResponse resp) 
throws ServletException, IOException { 
resp.setContentType("text/html"); 
resp.setCharacterEncoding("utf-8"); 
PrintWriter out = Writer(); 
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); 
out.println("<HTML>"); 
out.println("  <HEAD><TITLE>新会员增加失败</TITLE></HEAD>"); 
out.println("  <BODY>"); 
out.print("<h2>新会员增加失败</h2> "); 
@SuppressWarnings("unchecked") 
List<String> list = (List<String>)Attribute("errors");             
if(list != null){ 
for(String str:list){ 
out.println(str + "</br>"); 
} 
} 
out.println("<a href=\"" + ContextPath() + "/index.jsp\">返回注册页面</a> " );    //注意这边的解析 
out.println("  </BODY>"); 
out.println("</HTML>"); 
out.flush(); 
out.close(); 
} 
public void doGet(HttpServletRequest req, HttpServletResponse resp) 
throws ServletException, IOException { 
doPost(req, resp); 
} 
} 
package com.demo1.servlet; 
import java.io.IOException; 
import java.util.Map; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import com.demo1.java.User; 
public class LoginServlet extends HttpServlet { 
public static final long serialVervletUID = 1L; 
public void doGet(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 
this.doPost(request, response); 
} 
public void doPost(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException { 
String userName = Parameter("userName"); 
String password = Parameter("password"); 
if(checkLogin(userName, password)){ 
RequestDispatcher("/member.html").forward(request, response); 
}else{ 
response.sendRedirect("/Demo1/jsp/front/Login.jsp"); 
} 
} 
public boolean checkLogin(String userName, String password)throws NullPointerException{ 
User user = Instance(); 
Map<String, String> map = UserMap(); 
if(userName != null && !"".equals(userName) && password != null && !"".equals(password)){ 
String[] arr = (userName).split("##"); 
if(arr[0].equals(password)){ 
return true; 
} 
} 
return false; 
} 
} 
package com.demo1.servlet; 
import java.io.IOException; 
import java.io.PrintWriter; 
import javax.servlet.ServletException;