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Created by Fang on November 08, 2011 20:55:00    Last update: November 21, 2011 18:19:44
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:...
Created by alfa on May 24, 2011 15:59:41    Last update: May 24, 2011 15:59:41
Java reflection with Apache beanutils example. import org.apache.commons.beanutils.MethodUtils; ...
Created by Dr. Xi on June 11, 2010 23:11:59    Last update: June 11, 2010 23:14:02
Given a simple XML file like this: <?xml version="1.0"?> <root id="1"> ... Calling Document.getElementById returns null (surprisingly!): import java.io.*; import org.w3c.dom.*; impo... In fact the JavaDoc says something along the lines that getElementById returns the Element that has an ID attribute with the given value. An attribute with the name "ID" or "id" is not of type ID unless it is so defined. How is an attribute defined as an ID attribute ? With a DTD or schema. If you are not validating the XML, then the API is useless. So, what to do if you want to find an element for which the attribute named "id" has a given value? Several options were offered in GetElementById Pitfalls . One of them is to...
Created by Fang on April 01, 2010 22:24:58    Last update: April 02, 2010 02:49:38
In this note I'll show you how to create and package a JSP custom tag. The purpose of this tag is to display a random splash image for a home page, among a set of images. We should be able to add or delete candidate splash images from the WAR archive without the need to change the JSP. This is the intended use of the tag: <%@ taglib uri="http://custom.tag.com/demo" prefix... In the above example you provide a set of images named splash*.png (e.g., splash1.png, spalsh2.png, ...), and the tag will pick a random one to display when the JSP is rendered. Let's get started. I'll use Maven for this purpose. Create the standard Maven directory structure ./pom.xml ./src ./src/main ./src/main/jav... pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... SplashTag.java package tagdemo; import java.util.ArrayList......
Created by Dr. Xi on September 13, 2008 20:13:48    Last update: September 13, 2008 20:14:05
Use CreditCardValidator to validate credit card number. You need the commons-validator.jar from apache. package example; import example.datatypes.C...
Created by Dr. Xi on December 12, 2007 20:30:01    Last update: December 12, 2007 20:32:23
This is a script to tail a log file through the web browser. It uses AJAX, apache web server, mod_python, UNIX utilities tail (requires the --lines switch) and wc . The log file may reside on the web server or any other host accessible from the web server through SSH. Although it's written in python, it should be easy to port to other languages such as Perl. Apache httpd.conf : LoadModule python_module modules/mod_python.so ... Python script: import time, os from os.path import basename ...