spring-mvc-portlet

Basic spring mvc portlet in liferay

• Unlike a single controller for all actions in a generic portlet,a spring mvc portlet consists of:

  • DispatcherPortlet,which acts as front controller,delegating requests to,
  • Mapping Handler which subsequently delegates it to other controllers,based on the request mapping or directly to,
  • View Resolvers,which map to the subsequent
  • View

• Spring framework provides usage of Forms,data binding and Validation framework

• Provides exception resolvers and interceptors

Configuring a spring portlet

• Configuration in web.xml
  • Set portlet application context used by all portlets within a web app
  • Set ContextLoaderListener to load the parent context
  • Set contextConfigLocation for listing of bean definitions
  • Set ViewRendererServlet which acts as bridge between Servlet and Portlet requests
• Configuration in portlet.xml
  • Front Controller as DispatacherPortlet
  • Portlet's own contextConfigLocation
  • Bean definitions for a certain portlet are defined per portlet application context file while the ones shared between portlets should in a parent file
• The DispatcherPortlet uses HandlerMappings to determine which Controller should handle each PortletRequest.
• A DispatcherPortlet can use multiple HandlerMappings

Key take-aways from Spring mvc liferay portlet

• Namespacing of params should be disabled in liferay portlet using liferay-portlet.xml
  • 'requires-namespaced-parameters' should be set as false -Spring uses Validator framework to enable field level validations using Bean validation from JSR 303,whose implementation is provided by Hibernate
• Due to a bug,hibernate Validator can reference hashCode method on a null object,hence that needs to be handled in hashCode implementation of the bean class
• Mapping of bean class used for user interaction and actual model class should be done appropriately -In case of similar names,make sure the correct import is done

Update:

• Defining exception in service.xml

  • The generated source is a checked exception

  • Exception should be used only to validate a certain business rule on data rather than simply validating user input

  • In current case,we check if modified date is not after a certain defined business date,else the exception is thrown

  • LocalDate API from Java 8 is used which is more utilitarian in terms of available methods

    References: https://wiki.jasig.org/download/attachments/6619258/spring-portlet-mvc-tutorial_v1.pdf https://wiki.jasig.org/download/attachments/25362440/spring-portlet-mvc-seminar.pdf