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Created by Fang on March 30, 2012 10:07:25
Last update: March 30, 2012 10:09:08
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...
Created by Fang on February 23, 2012 14:25:57
Last update: March 01, 2012 13:53:59
Some example snippets for Spring message configuration and usage.
To configure a message source in Spring context (basename=messages):
<bean id="messageSource"
class="org.springf...
Locale change interceptor can also be setup with:
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
The messages file should be named messages.properties (or messages_en.properties , etc.) and located on CLASSPATH , for example: WEB-INF/classes .
To use a message resource in JSP:
<%@ taglib prefix="spring" uri="http://www.springf...
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 16, 2012 12:27:55
Last update: February 16, 2012 12:34:58
Here are some ways to run a main method using Maven:
Use the exec plugin:
mvn exec:java -Dexec.mainClass="com.example.App"
or, with arguments:
mvn exec:java -Dexec.mainClass="com.example.App" -...
Attach it to a build phase with the build element:
<build>
<plugins>
<plugin>
...
If you want to run main from Maven, it's probably just some test code. You are better off just to write a test case, or call the main method from a test class:
package com.example;
import junit.framework...
Created by James on February 02, 2012 16:09:05
Last update: February 02, 2012 16:09:17
flowplayer is another way to embed Flash in a web page. The code looks like this:
<object width="6400" height="380" data="swf/flowpl...
You need to download two swf files:
http://releases.flowplayer.org/swf/flowplayer-3.2.1.swf
http://releases.flowplayer.org/swf/flowplayer.controls-3.2.0.swf
Created by James on February 02, 2012 16:00:15
Last update: February 02, 2012 16:00:15
Video for Everybody seems to be a generic way to embed video in a web page, even without flash. This code snippet comes from that site.
<!-- first try HTML5 playback: if serving as XML, ...
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 Dr. Xi on February 01, 2012 12:55:28
Last update: February 01, 2012 12:55:28
You can define environment variables in the Tomcat context.xml file like this:
<?xml version="1.0" encoding="UTF-8"?>
<Context...
which is equivalent to the following in web.xml :
<env-entry>
<env-entry-name>varName</env-entr...
In Java code, the variable can be looked up like this:
// import javax.naming.Context;
// import javax...
Created by Fang on January 16, 2012 13:29:00
Last update: January 16, 2012 13:29:00
According to RFC 4627 , the MIME content type for JSON is application/json :
The MIME media type for JSON text is application/j...
So, in Java code:
servletResponse.setContentType("application/json")...
Created by Fang on December 05, 2011 13:04:11
Last update: December 05, 2011 13:04:11
Facelet requires strict XML syntax, so unmatched tags (start with no end, etc) generate errors. This is a trick to workaround that. The following code generates a row for every three items and for each row assigns a row id:
<!-- using ui:repeat -->
<ui:repeat var="name" ...
