After a user resets a password, I want to force the user to change the password before she gets access to secured content. This is usually done with a servlet filter. But with Spring MVC, you can also use a HandlerInterceptor . According to Spring JavaDoc: HandlerInterceptor is basically similar to a Servlet 2.3 Filter, but in contrast to the latter it just allows custom pre-processing with the option of prohibiting the execution of the handler itself, and custom post-processing. Filters are more powerful, for example they allow for exchanging the request and response objects that are handed down the chain. Note that a filter gets configured in web.xml, a HandlerInterceptor in the application context. As a basic guideline, fine-grained handler-related preprocessing tasks are candidates...

This is an example that uses tag handler, UI component and renderer together to support a custom taglib. The main purpose is to show how these components play together. The tag renders <ui:param name="extra" value="el interpreted"/> ... as <h3>my:foreach</h3> <ul class="css class" extra... These are the files: The tag handler ( src/main/java/com/example/ForeachTagHandler.java ): package com.example; import java.util.Map; ... The UI component ( src/main/java/com/example/UIForeach.java ): package com.example; import java.io.IOExcep... The renderer ( src/main/java/com/example/ForeachRenderer.java ): package com.example; import java.io.IOExcep... Faces config ( src/main/resources/META-INF/faces-config.xml ): <?xml version="1.0" encoding="UTF-8"?> <faces-c... Taglib config ( src/main/resources/META-INF/foreach.taglib.xml ): <?xml version="1.0" encoding="UTF-8"?> <facelet...

In the simple taglib example , I used a tag handler class to implement a taglib. This is an example to implement a taglib with a UI component. The purpose is to use a custom tag to split a string and print each part in a separate paragraph, i.e., print <p>john</p> <p>steve</p> <p>mike</p> with custom tag <my:foreach> : <my:foreach var="who" value="john steve mike"> ... These are the files: pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... src/main/java/com/example/UIForeash.java : package com.example; import java.io.IOExcep... src/main/resources/META-INF/faces-config.xml : <?xml version="1.0" encoding="UTF-8"?> <faces-c... src/main/resources/META-INF/foreach.taglib.xml : <?xml version="1.0" encoding="UTF-8"?> <facelet... How to use: Put the JAR file generated by the above project in the WEB-INF/lib folder of the web app. If the web app is a Maven project, just add the taglib project as a dependency:...

This is a step-by-step example to create a really simple facelet taglib (in JSF 2 with Maven). Create a simple Maven project with: mvn archetype:create -DgroupId=com.example -Dartif... Three files are created as a result: pom.xml src/main/java/com/example/App.java src/test/java/com/example/AppTest.java This project should be able to build with: mvn package Add facelet API dependencies to pom.xml : <project xmlns="http://maven.apache.org/POM/4.... The compiler plugin section is optional. Remove src/main/java/com/example/App.java , create a new Java class as the facelet Tag Handler ( HelloTagHandler.java ): package com.example; import java.io.IOExcep... This tag handler simply prints a "Hello" message. Create facelet tag declaration file src/main/resources/META-INF/hello.taglib.xml : <?xml version="1.0" encoding="UTF-8"?> <facelet... Build the JAR with mvn clean package Optionally, install it to the local repository: mvn install To use the taglib, simply drop the...

The following code validates a web.xml file against the web-app 2.5 schema: // Java XML validation with schema import java.... web.xml used for testing: <?xml version="1.0" encoding="UTF-8"?> <web-ap... According to Java API doc , validation can also be done while parsing by calling setSchema on the parsing factory. However, validation doesn't work for the SAXParserFactory! // Java XML validation with schema import java....

I tried to find a GZIP compression servlet filter to compress a large log file that we send down to the browser. Most of the implementations I found were overly complicated and many buggy. This is a simple implementation that worked for me. The filter: package filter.demo; import java.io.*; i... Config web.xml : <filter> <filter-name>gzipFilter</filte... The ugly anonymous inner class could have been avoided if the servlet API did not insist on ServletResponse.getOutputStream returning the bogus ServletOutputStream class (instead of the plain OutputStream ). Additional Note: In an earlier version of this filter, the gzip headers were added in doFilter , like this: // This is NOT good! if (supportsGzip) { ... It turned out that the ServletResponse methods sendError bypasses the gzip...

The tags XML transform tags apply XSLT to XML documents. The XML document may be specified as the doc attribute or enclosed as the body of the <x:transform> tag. Optional <x:param> tags may be used to specify parameters for the XSLT. <x:transform> Syntax: <x:transform doc="XMLDocument" xslt="XSLTStyle... or, include the XML document in the body: <x:transform xslt="XSLTStylesheet" [docSystem... Attributes: Name Dynamic? Type Description doc true String , Reader , javax.xml.transform.Source , org.w3c.dom.Document , or object exported by <x:parse> , <x:set> . Source XML document to be transformed. (If exported by <x:set> , it must correspond to a well-formed XML document, not a partial document.) xslt true String , Reader or javax.xml.transform.Source Transformation stylesheet as a String , Reader , or Source object. docSystemId true...

The tags XML flow control tags are exactly the same as their Core flow control equivalents, except that the test condition with a boolean EL expression is replaced by the select condition with an XPath expression. In the case of the forEach tag, the items attribute is replaced with the select attribute. In a test condition, the XPath expression is evaluated to a boolean value by the rules of the XPath boolean() function, which converts its argument to a boolean as follows: a number is true if and only if it is neither positive or negative zero nor NaN. a node-set is true if and only if it is non-empty. a string is true if and only if its length is non-zero. an object of...

The tags <x:parse> Parses an XML document. The document to be parsed can be specified by the doc attribute or enclosed as the body of the tag. The parsed document is exposed as the var attribute or the varDom attribute. When exposed as var , the type of the exposed object is implementation dependent; when exposed as varDom , the type of the exposed object is org.w3c.dom.Document . Objects exposed by var and varDom can both be used to set the context of an XPath expression. Syntax: <x:parse doc="XMLDocument" {var="var" [sco... or, put the XML document in the element body: <x:parse {var="var" [scope="page|request|s... Attributes: Name Dynamic? Type Description doc true String , Reader Source XML document to be parsed. systemId true String The...

JSTL string manipulation functions String manipulation functions are simple and self-evident. You just need to know that they exist. Test it Make these additions to the expanded test application : Create a new Java class StringManipulation : package jstl.demo.handler; import java.... Create a new JSP ( stringmanipulation.jsp ) under webapp : <%@ taglib uri="http://java.sun.com/jsp/jstl/c... Compile and package the WAR with: mvn package Deploy the WAR to a servlet container of your choice (for example, Tomcat or JBoss). Test the page with this URL (Tomcat/JBoss running on port 8080): http://localhost:8080/jstl-demo/demo/StringManipulation You may adjust the URL if your servlet container runs on a different port or the web app is bound to a different context root.