Troubles with apache tiles 2 and JSP
开发者_Python百科I'm trying to get tiles 2 working with JSP. I'm getting a null pointer exception. I'm having trouble finding good documentation that explains how to get setup. I have a pretty easy use case. I have a template with an attribute called "content". I'm then trying to use the template by inserting a jsp into the "content" attribute. I'm not sure if I need to set anything up in my web.xml file? I've pasted my template and the jsp that is trying to use the template.
Here is the template:
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib uri="http://tiles.apache.org/tags-tiles" prefix="template" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link rel="stylesheet" href="${pageContext.request.contextPath}/css/jquery-ui-1.8.5.custom.css" type="text/css" />
<link rel="stylesheet" href="${pageContext.request.contextPath}/css/app.css" type="text/css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.3/jquery.min.js" type="text/javascript"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/jquery-ui.min.js" type="text/javascript"></script>
<title>Cheetah Home</title>
</head>
<body>
<div id="wrapper">
<jsp:include page="${pageContext.request.contextPath}/jsp/layout/top.jsp"></jsp:include>
<template:insertAttribute name="content"></template:insertAttribute>
</div>
</body>
</html>
Here is a page trying to use the template:
<%@taglib uri="http://tiles.apache.org/tags-tiles" prefix="template" %>
<template:insertTemplate template="/templates/homeTemplate.jsp">
<template:putAttribute name="content" value="test.jsp">
</template:putAttribute>
</template:insertTemplate>
I'm using Maven to build the application, and I have the following dependencies specified:
<dependency>
<groupId>org.apache.tiles</groupId>
<artifactId>tiles-servlet</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>org.apache.tiles</groupId>
<artifactId>tiles-template</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>org.apache.tiles</groupId>
<artifactId>tiles-jsp</artifactId>
<version>2.2.2</version>
</dependency>
Everything builds fine, but when I run the application I get:
javax.servlet.ServletException: com.sun.jersey.api.container.ContainerException: org.apache.jasper.JasperException: java.lang.NullPointerException
Anyone have any ideas on how to get this working?
Thanks!
There is some configuration you must do to get Tiles 2 to work. The documentation (http://tiles.apache.org/tutorial/configuration.html) says you can configure web.xml to contain a startup servlet, a listener or a filter. I tried the listener and it did not work for me. However, the filter did.
<filter>
<filter-name>Tiles Filter</filter-name>
<filter-class>org.apache.tiles.web.startup.TilesFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>Tiles Filter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
Another problem that I ran into is that you need to specify an SLF4J implementation such as Log4J. Also be careful that when you add maven dependencies for tiles, that it will get the SLF4J api for you. You need to ensure that the implementation you specify in maven matches the version of the API that tiles added for you as a dependency, or you will run into some funny errors if you don't.
I get the same error, but it solved only by specifying an SLF4J implementation. Servlet works for me.
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