[英]how to disable direct access to pages from url for jsp pages
我創建了一個Web應用程序。 一切正常。但是,如果用戶還沒有登錄,他們可以通過URL訪問其他jsp頁面。 我想停止訪問網址。 我看到一些例子,它顯示了過濾器的用法。 我是過濾器的新手,我不知道如何實現它。 我正在使用servlets,dao和jsp頁面。
請建議我怎么做。 我想為所有jsp或servlets頁面制作一個過濾器。
web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<filter>
<filter-name>MyFilter</filter-name>
<filter-class>com.eis.servlet.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>MyFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>com.eis.servlet.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>DayWiseServlet</servlet-name>
<servlet-class>com.eis.servlet.DayWiseServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>RegisterServlet</servlet-name>
<servlet-class>com.eis.servlet.RegisterServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>RetrieveServlet</servlet-name>
<servlet-class>com.eis.servlet.RetrieveServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RetrieveServlet</servlet-name>
<url-pattern>/RetrieveServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>TimeSheet</servlet-name>
<servlet-class>com.eis.servlet.TimeSheet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TimeSheet</servlet-name>
<url-pattern>/TimeSheet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>DayWiseServlet</servlet-name>
<url-pattern>/DayWiseServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>RegisterServlet</servlet-name>
<url-pattern>/RegisterServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>/index.jsp</welcome-file>
</welcome-file-list>
<session-config>
<session-timeout>15</session-timeout>
</session-config>
</web-app>
loginservlet.java
public class LoginServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String n=request.getParameter("Emp_id");
String p=request.getParameter("Pwd");
String Usertype=request.getParameter("usertype");
HttpSession session = request.getSession(false);
if(session!=null){
session.setAttribute("name", n);
session.setAttribute("usertype", Usertype);
}
if(LoginDao.validate(n,p)){
RequestDispatcher rd=request.getRequestDispatcher("/daywise.jsp");
rd.forward(request,response);
}
else{
out.print("<p style=\"color:red\">Sorry Employee ID or password error</p>");
RequestDispatcher rd=request.getRequestDispatcher("/index.jsp");
rd.include(request,response);
}
out.close();
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
myfilter:
public class MyFilter implements Filter{
@Override
public void init(FilterConfig config) throws ServletException {}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)request;
HttpServletResponse resp = (HttpServletResponse)response;
if(null==((String) req.getSession().getAttribute("empid")) || ((String) req.getSession().getAttribute("empid")).equals("")){
chain.doFilter(req, resp);
} else {
resp.sendRedirect("/WebTimeSheet/index.jsp");
}
}
@Override
public void destroy() {}
}
Loginpage:
<form action="LoginServlet" method="post">
<fieldset style="width: 300px">
<legend> Login to App </legend>
<table>
<tr>
<td>User ID</td>
<td><input type="text" name="Emp_id" required="required" /></td>
</tr>
<tr>
<td>Password</td>
<td><input type="password" name="Pwd" required="required" /></td>
</tr>
<tr>
<td>User Type</td>
<td> <select name="usertype">
<option>Employee</option>
<option>Manager</option>
<option>Admin</option>
</select></td>
</tr>
<tr>
<td><input type="submit" value="Login" /></td>
</tr>
</table>
</fieldset>
</form>
</body>
<%@include file="/footer.jsp" %>
</html>
我所有的jsp頁面都在Web-inf文件夾之外的網頁文件夾中。 Web-inf文件夾只有web.xml init
header.jsp中
<c:choose>
<c:when test="${usertype eq 'Employee'}">
<div class="nav">
<ul><li class="container"><img src="${pageContext.request.contextPath}/images/enabling.jpg" /></li>
<li class="current"><a href="WEB-INF/daywise.jsp">DayWise TimeSheet</a></li>
<li><a href="WEB-INF/timesheet.jsp">Weekly TimeSheet</a></li>
</ul>
</div>
</c:when>
<c:when test="${usertype eq 'Manager'}">
<div class="nav">
<ul><li class="container"><img src="${pageContext.request.contextPath}/images/enabling.jpg" /></li>
<li class="current"><a href="/WEB-INF/daywise.jsp">DayWise TimeSheet</a></li>
<li><a href="WEB-INF/timesheet.jsp">Weekly TimeSheet</a></li>
<li><a href="WEB-INF/newemployee.jsp">Add New Employeer</a></li>
<li><a href="WEB-INF/retrieve.jsp">Retrieve TimeSheet</a></li>
</ul>
</div>
</c:when>
首先,JSP不應該用於提供請求,它們應該用於呈現視圖。 Servlet應該用於提供請求,然后轉發到JSP。
這是一個例子:
public class HelloWorld extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
//do some stuff
//forward to JSP to show result
String nextJSP = "/WEB_INF/result.jsp";
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(nextJSP);
dispatcher.forward(request,response);
}
}
在web.xml中:
<servlet>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>your.package.HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldServlet</servlet-name>
<url-pattern>/someurl</url-pattern>
</servlet-mapping>
在此示例中,servlet轉發到WEB-INF目錄中的JSP。 通過將所有JSP放在WEB-INF目錄中,這意味着無法直接請求它們。
現在你有一個Servlet,你可以設置一個Servlet過濾器:
public class MyFilter implements Filter {
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
if (isLoggedIn) {
//if user is logged in, complete request
chain.doFilter(req, res);
} else {
//not logged in, go to login page
res.sendRedirect("/login");
}
}
在web.xml中:
<filter>
<filter-name>MyFilter</filter-name>
<filter-class>your.package.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>MyFilter</filter-name>
<url-pattern>/secret/*</url-pattern>
</filter-mapping>
這樣,任何符合模式/secret/*
URL都將被過濾,以便需要登錄。
您可以在響應標頭中設置身份驗證cookie
Cookie someCookie = new Cookie("cookie_name","some_value" );
和, response.addCookie(someCookie)
然后,在您的過濾器內,您可以決定根據cookie值調用chain.doFilter(req, res)
。
你可以通過cookie.setMaxAge();
來控制cookie的年齡cookie.setMaxAge();
即。 注銷時將最大年齡設置為“0”。
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