Aaron Davis

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since Jun 03, 2016

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Recent posts by Aaron Davis

Having trouble with Filters - I cannot get this code to work. It compiles but doesn't run correctly.

I am basically using a MVC design pattern. It's simple, but there is one thing I cannot get to work.

The code for my DD is as follows:

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 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_3_0.xsd"
version="3.0">

<servlet>
<servlet-name>Ch3 Beer</servlet-name>
<servlet-class>com.example.web.BeerSelect</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Ch3 Beer</servlet-name>
<url-pattern>/SelectBeer.do</url-pattern>
</servlet-mapping>

<security-constraint>
<web-resource-collection>
<web-resource-name>BeerSelect</web-resource-name>
<url-pattern>/SelectBeer.do</url-pattern>
<http-method>POST</http-method>
</web-resource-collection>

<auth-constraint>
<role-name>admin</role-name>
</auth-constraint>
</security-constraint>

<security-role>
<role-name>admin</role-name>
</security-role>
<login-config>
<auth-method>FORM</auth-method>
<form-login-config>
<form-login-page>/WEB-INF/loginPage.html</form-login-page>
<form-error-page>/WEB-INF/loginError.html</form-error-page>
</form-login-config>
</login-config>

<filter>
<filter-name>BeerRequest</filter-name>
<filter-class>com.example.web.BeerRequestFilter</filter-class>
<init-param>
<param-name>LogFileName</param-name>
<param-value>UserLog.txt</param-value>
</init-param>
<filter-mapping>
<filter-name>BeerRequest</filter-name>
<url-pattern>/SelectBeer.do</url-pattern>
</filter-mapping>

</filter>
</web-app>

Now the code for my servlet (The controller is):

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.example.web;

import com.example.model.*;
import java.util.*;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
import javax.servlet.http.*;

/**
*
* @author Aaron
*/
public class BeerSelect extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
String c = request.getParameter("color");
BeerExpert be = new BeerExpert();
List result = be.getBrands(c);

request.setAttribute("styles", result);
RequestDispatcher view = request.getRequestDispatcher("result.jsp");
view.forward(request, response);
}
}

The code for my model is:

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.example.model;
import java.util.*;

/**
*
* @author Aaron
*/
public class BeerExpert {
public List getBrands(String color) {
List brands = new ArrayList();
if(color.equals("amber")) {
brands.add("Jack Amber");
brands.add("Red Moose");
}
else {
brands.add("Jail Pale Ale");
brands.add("Gout Scout");
}
return brands;
}
}

The code for the view is :

<%--
Document : result
Created on : Jun 2, 2016, 12:50:03 PM
Author : Aaron
--%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<%@ page import="java.util.*" %>
<html>
<body>
<h1 align="center">Beer Recommendations JSP</h1>

<%
List styles = (List)request.getAttribute("styles");
Iterator it = styles.iterator();
while(it.hasNext()) {
out.print("<br>try: " + it.next());
}
%>

</body>
</html>

I have a form based authentication which I know is written correctly but I will copy it just in case:

<!DOCTYPE html>

<html>
<body>
Please login daddy-o
<form action="j_security_check">
<input type="text" name="j_username">
<input type="password" name="j_password">
<input type="submit" value="Enter" />
</form>
</body>
</html>

Here is the code for the LoginError page:

<!DOCTYPE html>

<html>
<body>Sorry dude, wrong password</body>
</html>

And here is the code for the index.html (Where you start):

<!DOCTYPE html>

<html>
<body>
<h1 align="center">Beer Selection Page</h1>
<form method="POST" action="SelectBeer.do">
Select beer characteristics

Color:
<select name="color" size="1">
<option value="light">light</option>
<option value="amber">amber</option>
<option value="brown">brown</option>
<option value="dark">dark</option>
</select>

<center>
<input type="SUBMIT" />
</center>
</form>
</body>
</html>

Here is the code for the filter for authentication:

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.example.web;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;

/**
*
* @author Aaron
*/
public class BeerRequestFilter implements Filter {
private FilterConfig fc;

public void init(FilterConfig config) throws ServletException {
this.fc = config;
}

public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
throws ServletException, IOException {
HttpServletRequest httpReq = (HttpServletRequest)req;
String name = httpReq.getRemoteUser();
if (name != null) {
fc.getServletContext().log("User " + name + " is updating");
}
chain.doFilter(req, resp);
}

public void destroy() {

}
}

So my question is every time I try to run this program I get a message after logging on that says "HTTP Status 500 - Unable to find match between the canonical context path [/Beer-V1] and the URI presented by the user agent [r=light1/SelectBeer.do]"

What am I doing wrong?

7 years ago

Servlets