#EnableZuulProxy doesn't work under a servlet 2.5 container. Is there any workaround to get spring-cloud zuul work under a servet 2.5 container?
Also I could not find the annotation processor of #EnableZuulProxy. Please provide the class which propesses #EnableZuulProxy so that I can better understand what this annotation really does.
Spring Cloud is meant to be run on servlet 3.0. That being said, it is possible to get #EnableZuulProxy running on servlet 2.5. I had to figure out a hack for this as I had to get this working in Tomcat 6.
The main issue is due to the ZuulConfiguration.class, which has the method:
#Bean
#ConditionalOnMissingBean(name = "zuulServlet")
public ServletRegistrationBean zuulServlet() { ... }
The issue here is that ServletRegistrationBean uses javax.servlet.Registration$Dynamic, which is not available until Servlet 3.0. This results in a NoClassDefFoundError.
To work around this, use the spring-boot-legacy project to first register a DispatcherServlet. Secondly, you'll have to manually create a zuul servlet.
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>com.dm.gateway.microservicegateway.Application</param-value>
</context-param>
<listener>
<listener-class>org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener</listener-class>
</listener>
<filter>
<filter-name>ContextLifecycleFilter</filter-name>
<filter-class>com.netflix.zuul.context.ContextLifecycleFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>ContextLifecycleFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextAttribute</param-name>
<param-value>org.springframework.web.context.WebApplicationContext.ROOT</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<servlet-name>zuul</servlet-name>
<servlet-class>com.netflix.zuul.http.ZuulServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>appServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>
I found the best way to remove the auto servlet registration, is to just make a verbatim copy of ZuulConfig called ZuulOverrideConfig, and remove the zuulServlet() method. This is because the ZuulProxyConfiguration extends ZuulConfiguration, and it seemed to create the bean even when i tried to override it. I'm not 100% on the mechanics behind this, so there may be a better way.
The second change I made in ZuulOverrideConfig was to call an extended implementation of ZuulFilterInitializer, called 'LegacyZuulFilterInitializer`. This is because for some reason, the Zuul servlet was being crated, and able to be invoked, but no filters were bootstrapped. This extension is a hacky way to get the filters to bootstrap.
Next, I created a copy of ZuulProxyConfiguration called ZuulLegacyProxyConfiguraiton, and had it extend ZuulOverrideConfig.class.
Finally, I annotated the Application class as follows.
#EnableCircuitBreaker
#EnableDiscoveryClient
#Import(ZuulLegacyProxyConfiguration.class)
#SpringBootApplication
public class Application {....}
After all these hacks, the implementation finally worked as expected. I wouldn't suggest using this for long, as it's pretty hacky. You won't get configuration class updates automatically when moving to new versions, and I can't guarantee that something won't break randomly!
This is using Spring Cloud 1.1.4.RELEASE
Gist of all the code.
#EnableZuulProxy is from Spring Cloud which is based on Spring Boot which is Servlet 3.0 and above. If you need to use Servlet 2.5 you can use the Netflix APIs directly.
#EnableZuulProxy is meta-annotated with #Import(ZuulProxyConfiguration.class) so I guess that's what you mean when you say "propesses"? If you don't know what an #Import is, go and read up on Spring.
Related
I am just starting out trying to see what spring flow is about.This book that i have is describing how i have to configure the dispathcer-servlet.xml and create some flows in there.
Problem is i cannot find this dispatcher-servlet.xml file in my java spring application to start the configuration.Where is it?
I searched on here and on google but i only find people who already have n dispatcher-servlet.xml file and they are asking how to configure it.
Any help would be greatly appreciated!
You don't need dispatcher-servlet.xml to configure DispatcherServlet. It's just a default name Spring will look for if not defined. You can define config in contextConfigLocation init-param when defining DispatcherServlet in web.xml. Or, if you have single DispatcherServlet, you can use global spring xml configuration. If you have a working java spring application, look for
<context-param>
<param-name>contextConfigLocation</param-name>
...
</context-param>
or
<servlet>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
...
</servlet>
in your web.xml
If you don't find it in web.xml, you will have to configure it yourself. I also think that the book might be for webflow 1.x. Try using official Spring Webflow reference, it's a good starting point, and is up-to-date:
https://docs.spring.io/spring-webflow/docs/current/reference/html/
Specifically, for Dispatcher servlet configuration look at this chapter:
https://docs.spring.io/spring-webflow/docs/current/reference/html/spring-mvc.html#spring-mvc-config-web.xml
I am trying to setup Angular 7 with a maven based back-end java project into a single war file. At the moment I am trying to configure the web.xml file where I am currently having this problem. I am not sure at all if my approach is valid or 'good' therefore I will first describe what I am trying to do (if you think better on this aspect please do correct me).
So I have a couple of JAX-RS classes which I'd like to serve as a REST API. For this purpose I have created corresponding javax.ws.rs.core.Application classes to provide these REST components. Then I am including the Application classes in the web.xml file. Below are the files:
web.xml
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>backend.backendservice.StammSolvaraJahrRestApplication</servlet-name>
<servlet-class>backend.backendservice.StammSolvaraJahrRestApplication</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>backend.backendservice.StammSolvaraJahrRestApplication</servlet-name>
<url-pattern>/rmz/*</url-pattern>
</servlet-mapping>
Another variation of web.xml that I tried
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>backend.backendservice.StammSolvaraJahrRestApplication</servlet-name>
<servlet-class>backend.backendservice.StammSolvaraJahrRestApplication</servlet-class>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>backend.backendservice.StammSolvaraJahrRestApplication</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>backend.backendservice.StammSolvaraJahrRestApplication</servlet-name>
<url-pattern>/rmz/*</url-pattern>
</servlet-mapping>
Application class
public class StammSolvaraJahrRestApplication extends Application {
#Override
public Set<Class<?>> getClasses() {
Set<Class<?>> sets = new HashSet<>();
sets.add(StammSolvaraJahrRest.class);
return sets;
}
}
The error that I get is: java.lang.ClassCastException: backend.backendservice.StammSolvaraJahrRestApplication cannot be cast to javax.servlet.Servlet and if I remove the <servlet-class> then I'll get No servlet class has been specified for servlet. I am following https://docs.oracle.com/cd/E24329_01/web.1211/e24983/configure.htm#RESTF183 and How to deploy a JAX-RS application? among others but it seems not to be working.
There are two ways to define your JAX-RS servlet.
1) With Application Subclass like the one you have, you can skip the web.xml config and just add the application annotation
#ApplicationPath("resources")
public class StammSolvaraJahrRestApplication extends Application
2) With web.xml config
<servlet>
<display-name>JAX-RS Servlet</display-name>
<servlet-name>package.hierarchy.StammSolvaraJahrRestApplication</servlet-name>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>package.hierarchy.StammSolvaraJahrRestApplication</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>JaxRSServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
If you skip the servlet mapping from the last one, it will use your your #ApplicationPath specified value, or "/resources" if the previous one is missing.
The problem is just what it says. This line in your web.xml requires a javax.servlet.Servlet:
<servlet-class>backend.backendservice.StammSolvaraJahrRestApplication</servlet-class>
Since an Application is not a javax.servlet.Servlet, you're getting the error at runtime when your XML file is processed.
If you can, I would suggest that you start with a Spring Boot starter application. Spring Boot handles all of this for you. It can even embed a Tomcat server inside a jar file so that you can run your server like a simple Java application. Doing this would save you having to worry about what you're dealing with here.
When using GWT we use this URL forms:
Debug:
http://127.0.0.1:8888/index.html?gwt.codesvr=127.0.0.1:9997#hash
Compiled:
http://127.0.0.1:8888/index.html#hash
I need to be able to access the underlying Rest API.
Which I need to map within the "root"
http://127.0.0.1:8888/{contentId}
However this will sure break the GWT application access, and that it will not be accessible anymore.
How can I make this work together, considering the main requirement to have the Rest API in the root?
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<context-param>
<param-name>resteasy.guice.modules</param-name>
<param-value>org.jboss.errai.ui.demo.server.MyModule</param-value>
</context-param>
<listener>
<listener-class>
org.jboss.resteasy.plugins.guice.GuiceResteasyBootstrapServletContextListener
</listener-class>
</listener>
<servlet>
<servlet-name>Resteasy</servlet-name>
<servlet-class>
org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Resteasy</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>
Edit:
The idea is that I should be able to do both:
http://127.0.0.1:8888/index.html#hash
and
http://127.0.0.1:8888/abc123
That is, to co-exist with the "GWT servlet" since both the GWT servlet and the Rest API "servlet" will be deployed in the same server and same webapp path.
Obviously you need to take care of root context in your own servlet. The basic idea is to map YourRoutingServlet to /* path and then handle get/post and other calls by analyzing the request path(gwt or rest) and delegate handling to appropriate servlet.
Depenging on you application specific you can extend e.g. gwt servlet(RemoteServiceServlet) and check request url and if this is a gwt url(with #hash) then just call super method, if not then delegate the req/resp to rest servlet.
This would also mean that you have to have instance of rest servlet in your servlet or you can use servlet redirects(which I would not suggest)
I have a UserCredetnialsDatSourceAdapter defined in my Spring app context file. I also have a custom filter added to the Spring via the DelegatingFilterProxy.
This filter is using the #Autowire to get a reference to the DataSource Bean. I also #Autowire the DataSource in my DAO. When I debug I see different instance id's to the datasource in the Filter and DAO instances. Why are there 2 instances whenthese are singletons by default?
I also fired up jvisualvm and I looked at the heap and all my beans in my app context have 2 instances? Thanks for any insight maybe the bean pre/post processing has something do with it or maybe I should not be using #Autowire in a Filter. Any help is apprciated. Thanks!
EDIT
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config-context.xml</param-value>
</context-param>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/web-context.xml,/WEB-INF/config-context.xml</param-value>
</init-param>
Interesting I think I see what it going on. There are 2 instances because there are 2 contexts. One for the app and 1 for each request (Thread) I assume? Is there a way to specfiy which context to use? Maybe filter is not the answer and I will need to use AOP. Need to research how to inject a bean in #Aspect, if that is even possible.
Thanks!!
-Joe
You are importing your /WEB-INF/config-context.xml as part of your Root Application Context(one loaded up by ContextLoaderListener) as well as your Web Context(loaded by DispatcherServlet). You can probably remove it from the one for DispatcherServlet.
I have a Spring ApplicationListener bean registered to listen for ContextRefreshed events. For some odd reason though, I get two calls to the onApplicationEvent(ContextRefreshedEvent) method at the completion of the context initialization. Is this normal behavior or is it indicative of a problem with my configuration? I'm using Jetty 8 for my Servlet container.
My relevant web.xml configuration is as follows
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/spring/spring-config.xml</param-value>
</context-param>
<servlet>
<servlet-name>Spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value></param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet-mapping>
<servlet-name>Spring</servlet-name>
<url-pattern>/service/*</url-pattern>
</servlet-mapping>
Thanks!
Even though you did not specify a contextConfigLocation for your DispatcherServlet it still creates a child context and the second refreshed event is for that context. Use event.getApplicationContext() to find out which context the event is for.
it happened to me as well, on a different event-listener. (ApplicationListener<AuthenticationFailureBadCredentialsEvent>)
I suspected the ContextLoaderListener, and when I removed the declaration from the web.xml, the app was working properly. Then I had to figure out what is its purpose, of the ContextLoaderListener...
Role/Purpose of ContextLoaderListener in Spring?
the interesting answer there is:
ContextLoaderListener is optional. Just to make a point here: you can
boot up a Spring application without ever configuring
ContextLoaderListener ...just the basic minimum web.xml with
DispatcherServlet
It looks like bug.
https://jira.springsource.org/browse/SPR-6589
If you are using 3.0 try it on the latest available release which is 3.05.
I had this problem too but fixed it. I was injecting the dataSource into my DAO (and instantiating a JdbcTemplate with it)....but I also had a Spring bean configured for JDBCTemplate.
I should have been injecting my DAO with the jdbcTemplate...that avoids the duplicate.