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Created by Fang on February 27, 2012 12:19:19    Last update: February 27, 2012 12:19:19
Mapping Java objects to Jackson JSON is pretty simple. But if you name a JSON field wrong, you'll get the "Unrecognized field ... (Class ...), not marked as ignorable" error. The rule for mapping a Java bean attribute name to a JSON field name is: lower all leading capital letters until the first lower case letter . For example, this Java class: package com.example; public class Person { ... maps to this JSON string: { "firstName": "Jane", "lastName": "... Test code: package com.example; import java.net.URL; ...
Created by Fang on February 21, 2012 20:33:58    Last update: February 21, 2012 20:33:58
You can customize Tomcat error page with error code: <error-page> <error-code>404</error-code> ... or Java exception type: <error-page> <exception-type>java.lang.Throwab... Either error-code or exception-type is required, but not both. There's no way to aggregate error codes, such as: <!-- This does not work! --> <error-page> ... Customizing error pages is about the only way to suppress the default stack trace in Tomcat in case of an unhandled exception.
Created by James on February 02, 2012 09:20:22    Last update: February 02, 2012 09:20:22
This example came from the jQuery validation documentation. The required rule can be used to validate a required selection box when you set the value of the first option to empty. <!DOCTYPE HTML> <html> <head> <scrip... The error message is the title since no error message is specified. A more fully defined validation check would look like this: $('#my-form').validate({ errorElement: "p", ...
Created by Fang on November 21, 2011 16:30:56    Last update: December 07, 2011 08:54:32
This is a series of notes on building custom JSF 2.0 facelet taglibs, ordered from the simplest to the less simple. Hopefully it can help you to get started on how to build custom taglibs for JSF. A simple JSF facelets taglib example The simplest taglib I can think of. Using EL expression with a custom tag Make tag attributes dynamic. Mixing custom tag with facelet ui taglibs Discover things you might run into when you get into more details. Which EL context to use? Using the wrong EL context can lead to subtle bugs. JSF facelet taglib backed by a UI component A UIComponent can be a tag handler, without being TagHandler . Using tag handler, UI component and renderer with a JSF facelet...
Created by Fang on November 28, 2011 21:04:15    Last update: November 28, 2011 21:04:15
Some innocent looking JavaScript may cause a fatal error in a Facelet page. For example: <script type="text/javascript"> if (items.lengt... or <script type="text/javascript"> // jQuery code ... Because Facelet is strict XML, therefore, < and > must be escaped. There are several ways to deal with this: Do not embed JS code directly in the page. Put the code in .js files and include it in the page with the src attribute. Put JS code in a CDATA section: <h:outputScript target="head"> <![CDATA... Use XML entities: <script type="text/javascript"> // jQuery code ...
Created by nogeek on November 03, 2010 20:52:49    Last update: November 23, 2011 08:54:44
My problem is simple: in my XML data, a timestamp is provided as a long integer (number of milliseconds since the "the epoch"). When I do XSLT, I want to display it as a readable string, such as "Mon Nov 01 18:08:48 CDT 2010". After hours of struggle, I found: It's not so easy to get the job done with JDK 1.6 There are tons of garbage on the web in this space (suggestions, code snippets that simply don't work) Simple Xalan extension functions was the only resource that's somewhat informative. Even there some of the examples don't work. Below is a list of what worked and what didn't. This works: <xsl:stylesheet version="1.0" xmlns:xsl="h... This does not (providing long value to Date constructor): <xsl:stylesheet version="1.0" xmlns:xsl="h......
Created by Fang on October 22, 2011 19:51:05    Last update: October 22, 2011 20:31:48
I built a very basic JSF application and deployed to Tomcat 7.0.22, but it failed with this error: Caused by: java.lang.ClassFormatError: Absent Code... That looks weird and I wasn't able to find a sensible explanation! So I copied the jsf-api-2.1.jar , which was downloaded from the java.net Maven repository by Maven, into a temp folder. And tested it with this simple program: public class ClassFormatErrorTest { public ... I also copied servlet-api.jar from Tomcat's lib folder to the temp folder. Sure enough it failed with the same error: C:\tmp>java -cp .;jsf-api-2.1.jar;servlet-api.jar ... But when I replaced the javax.faces.webapp.FacesServlet class with one I compiled from source, the error disappears! Conclusions: The jar file jsf-api-2.1.jar from java.net Maven repository is good for compilation only (cannot be used...
Created by magnum on October 09, 2011 19:53:26    Last update: October 09, 2011 19:53:50
#include <stdio.h> #include <stdlib.h> #incl... UNIXguide.net explains this option well: This socket option tells the kernel that even if this port is busy (in the TIME_WAIT state), go ahead and reuse it anyway. If it is busy, but with another state, you will still get an address already in use error. It is useful if your server has been shut down, and then restarted right away while sockets are still active on its port. You should be aware that if any unexpected data comes in, it may confuse your server, but while this is possible, it is not likely. It has been pointed out that "A socket is a 5 tuple (proto, local addr, local port, remote addr, remote port). SO_REUSEADDR just says that you...
Created by magnum on September 25, 2011 21:51:23    Last update: September 26, 2011 20:49:22
A simple socket client in C. #include <stdio.h> #include <stdlib.h> #incl...
Created by freyo on September 07, 2011 16:46:14    Last update: September 07, 2011 19:23:00
The Android unit test framework is based on JUnit 3 , not JUnit 4. Test cases have to extend junit.framework.TestCase or a subclass (such as android.test.InstrumentationTestCase ). Tests are identified by public methods whose name starts with test , not methods annotated with @Test (as in JUnit 4). An Android test suite is packaged as an APK, just like the application being tested. To create a test package, first you need to identify the application package it is testing. Google suggests to put the test package source in a directory named tests/ alongside the src/ directory of the main application. At runtime, Android instrumentation loads both the test package and the application under test into the same process. Therefore, the tests can invoke methods on...
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