我已经创建了一个网络应用程序。一切正常。但是，如果用户没有登录，他们仍然可以通过 url 访问其他 jsp 页面。我想停止 url 访问。我看到了一些示例，它显示了过滤器的用法。我是过滤器的新手，我不知道如何实现它。我正在使用 servlet、dao 和 jsp 页面。
请建议我如何去做。我想为所有 jsp 或 servlets 页面制作一个过滤器。
网络.xml
<?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);
}
}
我的过滤器:
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() {}
}
登录页面:
<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 页面都在 Web-inf 文件夹之外的网页文件夹中。 web-inf 文件夹只有 web.xml init
标题.jsp
<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>
最佳答案
首先，JSP 不应该用来处理请求，它们应该用来呈现 View 。 Servlet 应该用于处理请求，然后转发给 JSP。
这是一个例子:
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 转发到 WEB-INF 目录中的 JSP。通过将所有 JSP 放在 WEB-INF 目录中，这意味着它们不能被直接请求。
现在你有了一个 Servlet，你可以设置一个 Servlet 过滤器:
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>
这样一来，任何符合模式 /secret/* 的 URL 都将被过滤，以便需要登录。
关于java - 如何禁用从jsp页面的url直接访问页面，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33499088/