Servlet通過Cookie儲存使用者資訊，實現自動登入的demo.
阿新 • • 發佈：2019-01-24
開始介面HTML，跳轉到判斷是否有Cookie的Servlet.
SessionStartPage.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <form action="sessionindex.do" method="post"> <input type="submit" value="登入"> </form> </body> </html>
判斷是否有Cookie的Servlet.此處獲取Cookie的資料。
package cc.session; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.Cookie; /** * Servlet implementation class Index */ @WebServlet("/sessionindex.do") public class Index extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public Index() { super(); // TODO Auto-generated constructor stub } protected void processRequest(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { Cookie[] cookies=request.getCookies();//查詢瀏覽器儲存的本地Cookie,返回結果是陣列。 if(cookies!=null) { for(Cookie cookie:cookies) {//Cookie由name和value兩部分組成 String name=cookie.getName(); String value=cookie.getValue(); if("user".equals(name)&&"Daniel".equals(value)) { request.setAttribute(name,value ); request.getRequestDispatcher("/sessionuser.view").forward(request, response); return; } } } response.sendRedirect("SessionLogin.html"); } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //response.getWriter().append("Served at: ").append(request.getContextPath()); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //doGet(request, response); processRequest(request,response); } }
登入介面的Html
SessionLogin.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <form action="sessionlogin.do" method="post"> <label>名稱<input type="text" name="user" width="100"></label><br> <label>密碼<input type="password" name="password" width="100" title="長度6-10字元，必須包含字母和數字。"></label><br> 自動登入：<input type="radio" name="autologin" value="auto"><br> <input type="submit" value="登入"> </form> </body> </html>
登入的Servlet，此處建立Cookie,並將使用者存到Cookie中。
package cc.session;
import java.io.IOException;
import java.net.URLDecoder;
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;
/**
* Servlet implementation class SessionLogin
*/
@WebServlet("/sessionlogin.do")
public class SessionLogin extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SessionLogin() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//doGet(request, response);
request.setCharacterEncoding("UTF-8");
String user=URLDecoder.decode(request.getParameter("user"),"UTF-8");
String password=request.getParameter("password");
String autologin=request.getParameter("autologin");
if(user.equals("Daniel")&&password.equals("2018Daniel"))
{
if("auto".equals(autologin))
{//自動登入時，建立Cookie,儲存使用者名稱。
Cookie cookieLogin=new Cookie("user", user);
cookieLogin.setMaxAge(3*60);//設定儲存時間為3分鐘
response.addCookie(cookieLogin);
}
request.setAttribute("user", user);
request.setAttribute("password",password);
request.getRequestDispatcher("sessionuser.view").forward(request, response);
}
else {
response.sendRedirect("SessionLogin.html");
}
}
}
獲取Cookie和登入成功後的Servlet
package cc.session;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class SessionUser
*/
@WebServlet("/sessionuser.view")
public class SessionUser extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SessionUser() {
super();
// TODO Auto-generated constructor stub
}
private void processRequest(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException {
String user=(String) request.getAttribute("user");//forward過來的request,需要通過getAttribute方法獲得，不是getParameter
PrintWriter out= response.getWriter();
if(user==null)
{
response.sendRedirect("SessionLogin.html");
}
else {
out.println("<html><head><title>Servlet User</title></head><body>"+user+" Welcome!</body></html>");
}
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//response.getWriter().append("Served at: ").append(request.getContextPath());
//processRequest(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//doGet(request, response);
processRequest(request,response);
}
}