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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 Dr. Xi on March 24, 2011 12:11:14    Last update: March 24, 2011 12:22:03
This is the task: your client wants to know how the web application is used. That is pretty easy. A plethora of commercial tools or any of the free log analysis tools such as analog and AWStats would fit the bill. But here's the catch: they want to know not only what pages are visited by how many people and when, but also who logged in and did what. Your application is using form based authentication and therefore, everyone is anonymous in the web access log. What to do? This is a servlet filter that generates a web access log with authenticated user info that can be fed to log analysis tools such as analog and AWStats . Filter code (the output format is Apache...
Created by Dr. Xi on November 23, 2010 20:20:01    Last update: March 01, 2011 13:38:51
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...
Created by Dr. Xi on January 08, 2010 03:53:37    Last update: January 08, 2010 03:54:56
This is an Ant custom task to merge Properties files I lifted from http://marc.info/?l=ant-user&m=106442688632164&w=2 , with some minor bug fixes. Example usage: <taskdef name="mergeProperty" classname="ant.task.... Implementation: package ant.task.addon; import java.io.Buff...
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 ...