<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录网页</title>
</head>
<body>
<form action="login.do" method="post">
名称：<input type="text" name="user"><br>
密码：<input type="password" name="passwd"><br>
自动登录：<input type="checkbox" name="login" value="auto"><br>
<input type="submit" value="发送">
</form>
</body>
</html>
package cc.openhome;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//直接访问index.do 如果cookie中的确有信息 则可以直接登录
@WebServlet("/index.do")
public class Index extends HttpServlet {
protected void processRequest(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
Cookie[]cookies=request.getCookies();
if(cookies!=null)
{
for(Cookie cookie:cookies)
{
String name=cookie.getName();
String value=cookie.getValue();
if("user".equals(name)&&"caterpillar".equals(value))
{
request.setAttribute(name, value);
request.getRequestDispatcher("/user.view").forward(request, response);
return;
}
}
}
response.sendRedirect("login.html");
}
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//第一次登录 如果有使用登录会保存cookie
@WebServlet("/login.do")
public class Login extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String user = request.getParameter("user");
String passwd = request.getParameter("passwd");
if("caterpillar".equals(user) && "123456".equals(passwd)) {
String login = request.getParameter("login");
if("auto".equals(login))
{
Cookie cookie=new Cookie("user", "caterpillar");
cookie.setMaxAge(7*24*60*60);
response.addCookie(cookie);
}
request.setAttribute("user", user);
request.getRequestDispatcher("user.view")
.forward(request, response);
}
else {
response.sendRedirect("login.html");
}
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
}
package cc.openhome;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//这里先不使用jsp
@WebServlet("/user.view")
public class User extends HttpServlet {
protected void processRequest(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
if(request.getAttribute("user") == null) {
response.sendRedirect("login.html");
}
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC ‘-//W3C//DTD HTML 4.01" +
" Transitional//EN‘>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet User</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>"
+ request.getAttribute("user") + "已登录</h1>");
out.println("</body>");
out.println("</html>");
out.close();
}
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}
当然这里的账号密码是事先设计好的 实际开发中应该学会变通 从数据库读取信息
时间： 2024-11-05 15:47:54