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> ...

1. mvc:default-servlet-handler Configures a handler for serving static resources by forwarding to the Servlet container's default Servlet. Use of this handler allows using a "/" mapping with the DispatcherServlet while still utilizing the Servlet container to serve static resources. HandlerMapping: org.springframework.web.servlet.handler.SimpleUrlHandlerMapping Handler: org.springframework.web.servlet.handler.SimpleUrlHandlerMapping Attribute Description default-servlet-name The name of the default Servlet to forward to for static resource requests. The handler will try to auto-detect the container's default Servlet at startup time using a list of known names. If the default Servlet cannot be detected because of using an unknown container or because it has been manually configured, the servlet name must be set explicitly. 2. mvc:view-controller Defines a simple Controller that selects a view to render the response. HandlerMapping: org.springframework.web.servlet.handler.SimpleUrlHandlerMapping Handler: org.springframework.web.servlet.mvc.ParameterizableViewController Attribute Description...

These bean types are essential for the Spring MVC framework. I copied them here from the Spring Documentation for quick reference. Bean type Explanation HandlerMapping Maps incoming requests to handlers and a list of pre- and post-processors (handler interceptors) based on some criteria the details of which vary by HandlerMapping implementation. The most popular implementation supports annotated controllers but other implementations exists as well. HandlerAdapter Helps the DispatcherServlet to invoke a handler mapped to a request regardless of the handler is actually invoked. For example, invoking an annotated controller requires resolving various annotations. Thus the main purpose of a HandlerAdapter is to shield the DispatcherServlet from such details. HandlerExceptionResolver Maps exceptions to views also allowing for more complex exception handling code. ViewResolver Resolves logical String-based...

Validation groups can be used to control which rules validation rules to run. A validation group can be identified by any Java interface (not class!). Multiple validation groups may be specified when validating. In this example, I added a validation group named MyValidationGroup ( src/main/java/com/example/MyValidationGroup.java in Maven project): package com.example; public interface MyVal... and added a @Size rule for a person's name, because my database can only store up to 15 characters for a person's name: package com.example; import javax.validatio... Now validate Person with a JUnit test ( src/test/java/com/example/TestPersonWithGroup.java in Maven project): package com.example; import java.util.Set; ... Test with " mvn clean test ". The rules where groups is not specified, which belong to the javax.validation.groups.Default group, are not executed with these tests.

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...

Tomcat gzip compression filter can be turned on with " compression=on " in server.xml : <Connector port="8080" protocol="HTTP/1.1" ... The default compressed MIME types are: text/html,text/xml,text/plain . It would be nice to add other types: <Connector port="8080" protocol="HTT...

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.

Javadoc for javax.validation.Validation gives three ways to bootstrap JSR303 validation: Build default validator factory: ValidatorFactory factory = Validation.buildDefault... The logic for buildDefaultValidatorFactory is: if XML configuration ( META-INF/validation.xml ) defines a provider, use it. if XML configuration does not exist or does not define a provider, use the first provider returned by ValidationProviderResolver . Use custom ValidationProviderResolver : Configuration<?> configuration = Validation ... Ask for a specific provider by class: EXAMPLEConfiguration configuration = Validation ...

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...

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 .