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Created by Fang on December 06, 2011 19:03:25
Last update: December 07, 2011 08:54:11
Our custom tag, as implemented in the previous note , is broken when a template is used.
Create a template file ( home-template.xhtml ):
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Stric...
and a test page that uses it ( home.xhtml ):
<?xml version="1.0" encoding="UTF-8"?>
<ui:comp...
Then request the page with URL: http://localhost:8080/facelet-demo/home.jsf?name=Jack .
You'll find that our hello tag works inside ui:repeat but fails to get the value defined by ui:param ! What's the problem? Our hello tag implementation evaluated the EL with the wrong EL context!
This is the corrected implementation:
package com.example;
import java.io.IOExcep...
Created by Dr. Xi on November 11, 2011 10:05:22
Last update: November 11, 2011 10:12:01
This is an HTML image tag filter using Java regex. It takes a string, finds the img tags, replaces the src attribute with one provided by the filter, then adds a class name to the class attribute.
import java.util.regex.*;
import java.io.*;
...
Test file:
<div id="HTML snippet">
<img src="img/big/txt-m...
Created by freyo on May 13, 2011 15:45:29
Last update: September 20, 2011 08:08:12
This is an Android app that dumps any binarized xml file as plain text - to the sdcard on the device or emulator.
build.xml :
<?xml version="1.0" encoding="UTF-8"?>
<project...
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<man...
res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<Lin...
res/values/strings.xml :
<?xml version="1.0" encoding="utf-8"?>
<res...
src/com/android/xmltool/DumpXml.java
package com.android.xmltool;
import java.ut...
Screenshot
Pre-built APK can be downloaded from: http://code.google.com/p/android-binxml-dump/
Created by freyo on May 20, 2011 09:25:20
Last update: May 23, 2011 12:11:42
The javax.xml.crypto and javax.xml.crypto.dsig packages are not available in Android (as of version 2.3). Therefore, standard Java API does not work. But you can use the Apache Santuario library to do that. Here are the steps:
Download the xml security source distribution (curently version 1.4.4).
Build with ant.
Create your own library jar (only the apache classes, no javax):
jar -cf xmlsec-1.4.4.jar -C build/classes org
Copy xmlsec-1.4.4.jar to the libs directory of your Android project.
Here's the Java code:
import java.io.*;
import javax.xml.parsers.*;
...
Created by Dr. Xi on January 14, 2010 00:28:27
Last update: March 30, 2011 15:37:44
A task that a Java developer does so frequently is to find out where a certain class can be found - to resolve compilation errors, classpath issues, or version conflicts of the same class introduced by multiple class loaders. A long while back I wrote a simple Perl script to perform the task. Later I was informed that there are Swing based Jar Browser and Jars Browser . Then, there are a couple of shell one-liners:
# one liner 1 find -name "*.jar" -print0 | xarg... But all of them share the same problem: if a class is in a jar nested in another jar, it cannot be found. Such is the case for a class inside a jar under the WEB-INF/lib directory of a...
Created by Dr. Xi on March 30, 2011 13:43:05
Last update: March 30, 2011 13:45:27
Method 1 - use javap with verbose flag:
$ javap HelloWorld -verbose | head
Compiled fro...
Method 2 - use a utility class:
import java.io.*;
import java.nio.ByteBuffer;
...
According to the VM Spec , a Java class file has this structure:
ClassFile {
u4 magic;
...
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 Fang on August 17, 2010 21:08:13
Last update: August 17, 2010 21:08:13
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.
Created by Dr. Xi on July 19, 2010 21:58:34
Last update: July 23, 2010 21:37:23
Parsing XML in Java is really simple:
import java.io.*; import javax.xml.parsers.Docu... The parser implementation details are hidden behind the JAXP API. In case you want to know which parser implementation is used, this is what the JavaDoc for DocumentBuilderFactory.newInstance says: Use the javax.xml.parsers.DocumentBuilderFactory system property. Use the properties file " lib/jaxp.properties " in the JRE directory. This configuration file is in standard java.util.Properties format and contains the fully qualified name of the implementation class with the key being the system property defined above. The jaxp.properties file is read only once by the JAXP implementation and it's values are then cached for future use. If the file does not exist when the first attempt is made to read from it, no further attempts are made to...
Created by Dr. Xi on July 21, 2010 22:14:53
Last update: July 21, 2010 22:14:53
This is a Java program to test XPATH expressions with namespace option. It's been tested with JDK1.6.
import java.io.FileInputStream;
import java.uti...
Following Getting Started with XML Security , these are the test files:
Without namespace (patient.xml).
<PatientRecord>
<Name>John Doe</Nam...
With namespace (patient_ns.xml).
<med:PatientRecord xmlns:med="http://www.medic...
Test results:
C:\>java XPathExample patient.xml /PatientRecord/V...
