1.要建的文档，.java用servlet创建
2.建一张登陆表格 index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form name="f1" id="f1" action="<%=path %>/servlet/LoginServlet" method="post">
<table border="0">
<tr>
<td>Username:</td>
<td><input type="text" name="username" value="${un}"></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="password" name="password" value="${pw}"></td>
</tr>
<tr>
<td>Autologin:</td>
<td><input type="checkbox" name="auto" value="1"></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="Login"></td>
</tr>
</table>
</form>
</body>
</html>
3.建立预备登陆servlet，判断该用户名和密码是否已经存在，若是存在则呈现已经有用户名和密码的值。PrepareLogin.java
package com.amaker.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class PrepareLogin extends HttpServlet { /** * */ private static final long serialVersionUID = -8306532188182712167L; /** * Constructor of the object. */ public PrepareLogin() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { Cookie[] cs=request.getCookies(); if(cs!=null&&cs.length>0){ for(int i=0;i<cs.length;i++){ Cookie c=cs[i]; if(c.getName().equals("username")){ String value=c.getValue(); request.setAttribute("un", value); } if(c.getName().equals("password")){ String password=c.getValue(); request.setAttribute("pw", password); } } } request.getRequestDispatcher("/index.jsp").forward(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } public void init() throws ServletException { // Put your code here } }
4.修改index.html中
<TR>
<td>Username:</td> <td><input type="text" name="username" value="${un}"></td> </tr> <tr> <td>Password:</td> <td><input type="password" name="password" value="${pw}"></td>
</tr>
5.建立登陆的servlet,在提交后转到显示之前输入的显示用户名和密码的页面。LoginServet.java
package com.amaker.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public LoginServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username=request.getParameter("username");
String password=request.getParameter("password");
String auto=request.getParameter("auto");
if(auto!=null&&auto.equals("1")){
Cookie c1=new Cookie("username", username);
Cookie c2=new Cookie("password", password);
c1.setMaxAge(60*60*24*7);//保存的时间为一周
c2.setMaxAge(60*60*24*7);
response.addCookie(c1);
response.addCookie(c2);
}
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(" This is ");
out.print(this.getClass());
out.println(", using the GET method");
out.println("welcome,"+username+":"+password);
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
