Dynamically list servlets (and request urls)?

[Sam Seaweed]

I have this large very complex system and it contains several dispatchers and a few servlets that are defined in the web.xml file. One dispatcher in particular is a set of services.

Of course good documentation is important in this case, but the thought crossed my mind that it would be nice if I could create a page that dynamically listed the services available.

So the question is in two parts really
1. Can I programatically get a list of servlets and their mappings from the web.xml?
2. Can I programatically get a list of services bound via spring using RequestMapping annotations?

I hope that was not too confusing.

[Srikkanth Mohanasundaram]

Hi Sam,

Please check the following links which will help you create a documentation page for all the @RequestMapping annotations in the @Controller classes.

RequestMappingHandler

demo

When it comes to web.xml, I'm not too sure. You can parse like any other xml file and map the servlet and servlet-mapping elements I guess.

Thanks
Srikkanth

[Sam Seaweed]

It seems to be exactly what I want, but when I try it, I get

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customDispatcherDocumentation': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping xx.xxx.xxxx.web.servlet.custom.CustomDispatcherDocumentation.handlerMapping; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
	at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588)
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645)
	at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508)
	at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449)
	at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133)
	at javax.servlet.GenericServlet.init(GenericServlet.java:212)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1161)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:981)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4071)
	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4375)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:790)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:770)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:553)
        :
        :

For various reasons I am currently restricted to Spring version 3.1.0 if that could be the problem

[Prasad Krishnegowda]

Show us your XML/Java files, it looks like there is no matching bean defined.

[Sam Seaweed]

How is the bean definition supposed to look for the RequestMappingHandlerMapping? I cannot find anything on the subject.

The dispatcher and controller both work fine as long as I do not try to autowire a RequestMappingHandlerMapping instance into it.


My dispatcher config
<?xml version="1.0" encoding="ISO-8859-1"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd"> <context:component-scan base-package="xx.xxxx.xxxx.web.servlet.custom" /> <bean id="viewResolver" class="yy.yyyyyy.yyyy.web.view.DefaultInternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> <property name="prefix" value="/custom_jsp/" /> <property name="suffix" value=".jsp" /> <property name="mode" value="www" /> </bean> <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename" value="WebAppResources" /> </bean> </beans>

package xx.xxxx.xxxx.web.servlet.custom;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

@Controller
@RequestMapping("/documentation")
public class CustomDispatcherDocumentation {

	
	RequestMappingHandlerMapping handlerMapping;
	
	@Autowired
	public CustomDispatcherDocumentation(RequestMappingHandlerMapping h) {
		handlerMapping = h;
	}
	
	@RequestMapping(value="", method=RequestMethod.GET)
	public void show(Model model) {
		model.addAttribute("handlerMethods", handlerMapping.getHandlerMethods());
	}

}

[Prasad Krishnegowda]

can you create the RequestMappingHandlerMapping bean as below.

<bean name='handlerMapping' class='org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping'/>;

and autowire it in your CustomDispatcherDocumentation.

[Sam Seaweed]

I added the bean definition to my dispatcher XML (right after the component-scan definition), however, even without wiring the bean, all of the controllers fail with the following

javax.servlet.ServletException: No adapter for handler [controller-method-signature] : Does your handler implement a supported interface like Controller?

If I remove this bean definition, the other controllers start working again.

I cannot find anything in the logs about the dispatcher failing to initialize or any errors except that when I request a URL in the dispatcher that is mapped I get the above error.

[Sam Seaweed]

*Smack forhead* I was of course missing the annotation driven tag from my dispatcher configuration

<mvc:annotation-driven/>

So of course the autowiring could not work.

Big thanks for the help.