Servlet和Cookie綜合應用
阿新 • • 發佈：2019-01-09
太久沒寫東西了，上來灌灌水
Servlet間傳值及接收
import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; public class AServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { HttpSession session=request.getSession(); session.setAttribute("name", "LinDL"); request.getRequestDispatcher("b").forward(request, response); } }
轉發到頁面接收資料import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class BServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("session : "+request.getSession().getAttribute("name")); request.getRequestDispatcher("/index.jsp").forward(request, response); } }
另一個例子，cookie在頁面間的傳值<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>My JSP 'index.jsp' starting page</title> </head> <body> name: <%=session.getAttribute("name") %> </body> </html>
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 CServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Cookie cookie=new Cookie("p1", "v1");
cookie.setMaxAge(10);
response.addCookie(cookie);
request.getRequestDispatcher("d").forward(request, response);
}
}
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 DServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
Cookie[] cookies=request.getCookies();
for(Cookie cookie:cookies){
System.out.println("----------------------------------");
System.out.println("cookie name : "+cookie.getName());
System.out.println("cookie value : "+ cookie.getValue());
System.out.println("----------------------------------");
}
}
}
下面這個通過將資料儲存在cookie中，下次登入同個頁面時輸入框就有之前輸入的資料為預設值
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 {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String username=request.getParameter("username");
String password=request.getParameter("password");
Cookie cookie1=new Cookie("username", username);
Cookie cookie2=new Cookie("password", password);
response.addCookie(cookie1);
response.addCookie(cookie2);
}
}
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
<title>My JSP 'login.jsp' starting page</title>
</head>
<body>
<%
Cookie[] cookies = request.getCookies();
String username = "";
String password = "";
if (cookies != null) {
for (Cookie cookie : cookies) {
if (cookie.getName() != null
&& cookie.getName().equals("username")) {
username = cookie.getValue();
}
if (cookie.getName() != null
&& cookie.getName().equals("password")) {
password = cookie.getValue();
}
}
}
%>
<form action="loginServlet">
<input type="text" name="username" value="<%=username%>" /><br>
<input type="password" name="password" value="<%=password%>" /><br>
<input type="submit" value="提交" />
</form>
</body>
</html>