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Created by Fang on April 16, 2012 13:32:10
Last update: April 16, 2012 13:32:10
There are two steps to create a custom function for JSP:
Declare the function in the TLD:
<?xml version="1.0" encoding="UTF-8" ?>
<taglib...
Implement the function (must be static):
package com.example;
public class UrlTransl...
To use the function:
<%@ taglib uri="http://www.example.com/jsp/tags" p...
Created by Fang on March 30, 2012 15:04:04
Last update: March 30, 2012 15:04:04
Spring MVC 3.1 can send either JSON or HTML response on the same URL, depending on the type of response requested. With this mechanism, a page can be sent when directly requested from a link, but a JSON response can be sent in response to an AJAX request. This is the controller code:
package com.example; import java.util.Map; ... In the above example, JSON response will be sent when the HTTP request contains header "Accept: application/json". HTML response will be sent then the header is "Accept: */*", or "Accept: text/html", or anything else. You can add a limitation that the HTML response does not produce "application/json". But then the question is which response will be sent when the HTTP header is "Accept: */*"? Both methods will...
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 March 15, 2012 10:24:35
Last update: March 15, 2012 10:24:35
Suppose that I have an email field annotated with:
@NotEmpty(message="Please enter email address")
...
Bean validation will trigger two errors when no email address is entered:
the email field is empty
an empty email field is not a valid email address
Displaying both errors to the user with <form:errors> would be redundant and confusing:
<%@ taglib uri="http://www.springframework.org/tag...
This is how to display the first error only:
<spring:bind path="emailAddress">
<c:if test="$...
Created by Fang on March 02, 2012 13:23:35
Last update: March 02, 2012 13:23:35
The landing page after login can be configured with the default-target-url attribute of form-login . If a user was redirected to the login form after requesting a restricted URL, she's redirected to the original requested page after successful login.
An easy configuration looks like this:
<beans:beans xmlns="http://www.springframework.org...
But there are times that you want to do more initialization after login (such as loading user data), or apply more complex logic before redirecting. This is where the authentication-success-handler-ref attribute comes into play. You create a class that implements org.springframework.security.web.authentication.AuthenticationSuccessHandler and use that as the authentication-success-handler-ref :
<http
entry-point-ref="authProcessFilterEn...
This is a skeleton implementation:
public class MyAuthenticationSuccessHandler implem...
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 10, 2012 16:17:13
Last update: February 10, 2012 16:17:13
The annotation @org.hibernate.annotations.Type overrides the default hibernate mapping type used for a column. This can usually be omitted since Hibernate normaly infers the correct type to use.
But @Type is required in ambiguous scenarios such as a java.util.Date attribute, which can map to SQL DATE , TIME or TIMESTAMP . You use the @Type("timestamp") annotation to tell Hibernate that a timestamp converter should be used, which identifies an instance of org.hibernate.type.TimestampType .
@Type can also be used to identify custom type converters, which can be defined with @TypeDef at the class level:
@TypeDefs(
{
@TypeDef(
na...
or with an xml file:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mappi...
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 Fang on January 31, 2012 15:40:34
Last update: January 31, 2012 15:41:28
This is a simple Hello World application with Spring 3 MVC. Like the default Apache HTTPd welcome page, it displays " It works! " when successfully deployed. The sole purpose is to show the minimum elements needed to setup Spring 3 MVC.
I use Maven since it's so much easier than downloading the dependencies manually.
Directory layout:
./src
./src/main
./src/main/webapp
./src/...
pom.xml :
<?xml version="1.0" encoding="UTF-8"?>
<project...
WEB-INF/web.xml :
<?xml version="1.0" encoding="UTF-8"?>
<web-app...
WEB-INF/applicationContext.xml (empty, but needed):
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
WEB-INF/spring-servlet.xml :
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
WEB-INF/jsp/home.jsp :
<!DOCTYPE html>
<html>
<head>
<title>H...
Build with:
mvn clean package
The resulting webapp is target/springmvc.war .
Created by Fang on January 31, 2012 13:57:56
Last update: January 31, 2012 15:04:29
These are the minimum steps to configure Spring MVC in web.xml :
Bootstrap Spring MVC by registering ContextLoaderListener :
<listener>
<listener-class>
org.springfra...
Register the DispatcherServlet :
<servlet>
<servlet-name>spring</servlet-name>
...
Add servlet-mapping :
<servlet-mapping>
<servlet-name>spring</servle...
Configure DispatcherServlet with WEB-INF/spring-servlet.xml , which configures WebApplicationContext specific to this servlet.
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
Optionally, use context-param in web.xml to configure the global WebApplicationContext :
<!-- XmlWebApplicationContext is the default, so t...
If you omit this section, you have to create file WEB-INF/applicationContext.xml , even if it's empty.
This is the full web.xml :
<?xml version="1.0" encoding="UTF-8"?>
<web-app...