Notes by Fang
Displaying keyword search results 1 - 10
Created by Fang on May 17, 2012 19:31:39
Last update: May 17, 2012 19:31:39
To inject ServletContext into a Spring bean:
implement ServletContextAware :
import javax.servlet.ServletContext;
import...
Define bean in Spring application context:
<beans:bean id="myBean"
class="com.example.M...
Created by Fang on May 03, 2012 15:07:17
Last update: May 03, 2012 15:07:52
Scaling an image with default Java API loses quality (horribly!):
public static BufferedImage resizeImage(Buffer...
The imgscalr library does the job beautifully. And its' very easy to do:
// import org.imgscalr.Scalr;
public static...
To import the library in Maven:
<dependency>
<groupId>org.imgscalr</groupId>
...
Created by Fang on April 16, 2012 12:58:35
Last update: April 16, 2012 12:58:35
To implement a JSP custom tag with dynamic attributes (for example, to pass-thru arbitrary attributes not handled by the JSP tag):
Set the dynamic-attributes element to true in the TLD:
<tag>
<name>mark</name>
<tag-class>c...
The tag handler must implement javax.servlet.jsp.tagext.DynamicAttributes :
package com.example.jsp;
import java.io.*;
...
Created by Fang on February 24, 2012 14:38:06
Last update: April 06, 2012 13:19:29
Step 1: create a Json factory:
package com.my.service.dev;
import java.io....
Step 2: use it:
ObjectMapper mapper = new ObjectMapper(new AllowCo...
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 28, 2012 12:30:22
Last update: March 28, 2012 12:30:36
To check password against login credential:
// import org.springframework.security.authenticat...
To replace authentication credentials with a new one:
SecurityContext securityContext = SecurityContextH...
Created by Fang on March 16, 2012 12:35:26
Last update: March 16, 2012 12:35:26
To programmatically resolve a spring message:
// import org.springframework.web.servlet.support....
Created by Fang on March 06, 2012 14:38:52
Last update: March 06, 2012 15:56:45
This may or may not be useful, but I did the research so here's the code.
import org.springframework.beans.factory.annotatio...
Created by Fang on March 06, 2012 12:25:33
Last update: March 06, 2012 12:25:33
In the bean validation API javadoc, for every constraint annotation, there's a corresponding .List annotation. For example, for @NotNull , there's @NotNull.List , for which JavaDoc says: Defines several @NotNull annotations on the same element What would you accomplish with multiple @NotNull annotations that you cannot accomplish with one @NotNull ? This is a test to reveal some of the facts. Change the Person class to:
package com.example; public class Person { ... Add another JUnit test ( src/test/com/example/TestPersonWithList.java ): package com.example; import java.util.Itera... As the test shows, a Person bean can never be valid because we are requiring that name must begin with Mr and Ms . One might think that the same can be accomplished by simply repeating the @Pattern annotation multiple times,...
