I'm currently developing a Java backend together with JHipster 3 and ran into a problem I don't seem to be able to solve very easily.
I would like to serve static assets – in this case images – from a folder outside of the project in addition to the default front-end generated by JHipster. As of default JHipster seems to serve static assets from one directory out of two depending on environment, as configured in main/java/config/WebConfigurer.java. I would like to point /public/** to a folder in my home catalogue but keep the /** mapping for the Angular front-end.
In general Spring projects you seem to be able to add other sources for static assets by extending WebMvcConfigurerAdapter and override the addResourceHandlers method, but that doesn't seem to have an effect in my case. Adding the #EnableWebMvc annotation breaks the default JHipster mapping for their front-end. If I don't add the annotation I don't even seem to reach handleRequest() in DefaultServletHttpRequestHandler which handles the mapping to the correct servlet.
I can't give any other information on the subject at the moment, but I'm hoping someone with knowledge on JHipster will see this and point me in the right direction.
Thanks in advance, Max.
All app servers have an option to provide additional locations for class path.
For example, Tomcat's property is 'common.loader' in conf/catalina.properties.
You can then use e.g. Spring's ClassPathResource to load a resource manually, or just use a construct like '#Value("classpath:abc.txt") Resource r' to inject something known in advance.
Related
I am creating a library using spring-boot (v2.1.6.RELEASE) as a starter project that will facilitate as base extension jar responsible for configuring and starting up some of the components based on client project properties file.
The issue I am facing is that if the client project's SpringBoot Application class contains the same package path as library everything works like charm! but when client project contains different package path and includes ComponentScan, it is not able to load or start components from the library.
Did anyone encounter this issue? how to make client application to auto-configure some of the components from library jar?
Note: I am following the library creation example from here: https://www.baeldung.com/spring-boot-custom-starter
There are many things that can go wrong here, without seeing relevant parts of actual code its hard to tell something concrete. Out of my head, here are a couple of points for consideration that can hopefully lead to the solution:
Since we use starters in our applications (and sometimes people use explicit component scanning in there spring applications) and this obviously works, probably the issue is with the starter module itself. Don't think that the fact that the component scan is used alone prevents the starter from being loaded ;)
Make sure the starter is a: regular library and not packaged as a spring boot application (read you don't use spring boot plugin) and have <packaging>jar</packaging> in your pom.xml or whatever you use to build.
Make sure you have: src/main/resources/META-INF/spring.factories file
(case sensitive and everything)
Make sure that this spring.factories file indeed contains a valid reference on your configuration (java class annotated with #Configuration). If you use component scanning in the same package, it will find and load this configuration even without spring factories, in this case, its just kind of another portion of your code just packaged as a separate jar. So this looks especially "suspicious" to me.
Make sure that #Configuration doesn't have #Conditional-something - maybe this condition is not obeyed and the configuration doesn't start. For debugging purposes maybe you even should remove these #Conditional annotations just to ensure that the Configuration starts. You can also provide some logging inside the #Configuration class, like: "loading my cool library".
I'm having issues with a custom Spring Boot starter. How can a starter cause a profile to be included and pull related configuration from a config server?
Perhaps my use case is unique, because I haven't found any helpful information online. I'm working in an enterprise environment and this starter is for use by my team, so we're able to control some things (like profile names) that perhaps wouldn't make sense in the open source world.
Here is the scenario: We have a Spring Cloud Config Server running to provide configuration. Across our Spring Boot projects, we have standardized on certain profile names such as "prod" and "nonprod" to control configuration in our different environments. I am trying to create a starter to provide reusable functionality. For example purposes, let's say I'm creating a starter that provides an interface to an appliance that performs cryptographic work for us. This starter will need the IP address of the appliance and various other configuration which differs between production and non-production.
Within the config repo, I will have files such as application.yml, application-nonprod.yml, application-nonprodEncryption.yml, etc.
My goal is to have the custom encryption starter automatically include the nonprodEncryption profile when that starter is included in an application. By doing this, apps which don't need encryption do not load the encryption related properties.
Here are my experimental findings so far:
Within an application's bootstrap.yml, I can put a block such as
spring.profiles: nonprod
spring:
profiles:
include:
- nonprodEncryption
and that produces the desired result (i.e. the application-nonprodEncryption.yml file is loaded from the config server and used), but this is an undesirable solution as every app that uses my custom starter would need to include this boilerplate configuration.
When I move the above configuration to the starter's bootstrap.yml, it seems to have no effect.
When I move the above configuration to the starter's application.yml, it seems to be applied (i.e. it shows up in the The following profiles are active: list), but it is too late in the lifecycle to cause the appropriate configuration to be pulled from the config server.
Other things I've considered:
Why not just put all of the configuration into the main profile config file (e.g. application-nonprod.yml)? From a separation of concerns and maintenance standpoint, I'd like to keep configuration for individual starters isolated from each other. Also, some configuration data is more sensitive than other config data, so I don't like the idea of exposing all of the configuration to all apps, since many apps won't need some of the more sensitive configuration. Yes, they could get to it, but why load it into their memory if they don't need it?
Why not just specify the extra profiles when we launch the app? These apps will be running on a cloud platform. The platform will specify either "prod" or "nonprod" as the profile based on which tier the app is running in. I want to manage that at the platform level rather than the app level, so I want the list of profiles provided at app launch to be uniform across all apps (add adding, for example, nonprodEncryption to the list just gets me into the same situation as above - all apps would have all of the configuration, so I might as well just put it all in a single file).
We are currently using Spring Boot 1.5.10.
Any thoughts on how to achieve what I'm trying to do?
I finally found a solution (in case anyone else finds themselves in the same spot).
Step 1: Add a configuration class like this to your starter:
package com.company.bootstrap;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Profile;
#Configuration
#Profile("nonprod")
public class BootstrapNonprod {
public BootstrapNonprod(ConfigurableApplicationContext ctx) {
ctx.getEnvironment().addActiveProfile("nonprodEncryption");
}
}
This will conditionally add a profile. In this example, whenever the "nonprod" profile is active, this class will add the "nonprodEncryption" profile.
Step 2: In your starter's spring.factories file, add a line such as this:
org.springframework.cloud.bootstrap.BootstrapConfiguration=com.company.bootstrap.BootstrapNonprod
It seems like it is just that simple.
I'm developing some Spring applications using Spring Boot 1.4.1 and spring-boot-starter-thymeleaf dependency. I wish to share my Thymeleaf templates (such as header and footer) on my webserver to be able to include them in my applications. The easiest way to achieve this would be to include server root relative link to my templates in each of my apps. This way, my apps will be portable and I can get it to work seamlessly on all my environments (dev, test, prod).
From my perspective, this seems not to be a big deal since the server-relative URLs are already taken into account by Thymeleaf
<th:block th:replace="#{~/my/share/header}" />
However I can't get it to work. I always get an error like
Error resolving template "/my/share/header", template might not exist or might not be accessible by any of the configured Template Resolvers
I can confirm that my template is available because http://localhost/my/share/header.html is responding correctly (btw: I'm using Apache httpd to host my apps so I'm using the same port).
I've also tried to add ".html" at the end of the URL or implement the URLTemplateResolver (see below) but unfortunately, nothing seems to work.
#Bean
public ITemplateResolver templateResolver() {
UrlTemplateResolver templateResolver = new UrlTemplateResolver();
templateResolver.setSuffix(".html");
return templateResolver;
}
Does someone knows how to embed templates using server root relative URLs?
It sounds like there's no way to achieve this in the current version of Thymeleaf as you can see in this GitHub post. My workaround is to use the UrlTemplateResolver as described in the initial post and add a variable in my Spring Boot project (application.properties). This way, I can manage different URL depending of my deployment environments.
what's the easiest way to get the spring boot goodness but not try to autoconfigure all the things? For instance, to only run flyway with our already configured properties (some loaded via Consul + Spring Cloud), I was hoping I could do something like:
#Configuration
#Import({DataSourceAutoConfiguration.class, FlywayAutoConfiguration.class})
public class FlywaySetup {}
and have the main method just call SpringApplication.run(FlywaySetup.class)
The problem with this is it picks up all the Component Scan / crazy long list of other dependencies. Any way to specifically configure the dependencies (but still get the nicities of the framework)
If you run this app, it shouldn't use component scan at all. There's nothing that triggers component scan in spring boot besides #ComponentScan (that's available on #SpringBootApplication).
It would help if you could provide more accurate details rather than "crazy long list of other dependencies.". Running that FlywaySetup should only load those two configuration classes (important: these are not handled as auto-configuration anymore). If you have component scan, there's something else you're not showing.
You can exclude auto-configurations you don't need.
You may want to take a look at this SO answer to explore mechanism how to do that.
I'm having a problem I simply can't get my head around.
I'm creating a jsf application where I (as administrator) can upload a jar file, and that way around update the application.
Through this tutorial: http://docs.oracle.com/javase/tutorial/deployment/jar/jarclassloader.html I have managed to classload the jar file. The first issue is that I can only class load as "Object" and not cast to an other class type. I get a ClassCastException.
JarClassLoader jcl=new JarClassLoader(url);
Class cl= jcl.retreiveClass(jcl.getMainClassName());
Object ob=cl.newInstance(); //I would like to make this a RouteBuilder object instead of Object
Concretely I'm using Apache Camel, where I can add routes to an existing "core" (CamelContext). What's happening is that I have the core of apache camel running in my web app, and I can then add routes runtime. It's a route I want to package as a jar and load into the app runtime (I want to develop and test the route in my local environment, and then afterwords upload it to the production application). A concrete route is just a simple java class that extends RouteBuilder. I want to upload the jar, classLoad (URLClassLoader) the main class (maybe the whole jar? - does that make sense?), and convert it to a RouteBuilder. This seems to be impossible. I have chosen to upload the jar file to a folder outside my war, so that the routes do not get erased when I restart the webapp (is this smart or should this be done in an other way?). Is that a problem regarding name spaces? Furthermore, I haven't been able to find out whether I need to traverse my entire jar file and classload ever single class inside. Any comments on that?
To me it seems like I have some fundamental misconceptions on how extending / updating a java application is done. I simply can't find any good examples/explanations on how to solve my problem and therefore I conclude that I don't get this on a conceptual level.
Could someone elaborate on how to extend a running jsf application (I guess the same issues are relevant in native java apps), explain how to upload and class load a jar at runtime, and how to cast loaded classes to other class types than Object?
Thanks
Lasse
If you are interested in loading Routes without stopping your application you could consider using an OSGi container like Karaf. Karaf provides support for Apache Camel routes out-of-the-box: http://camel.apache.org/karaf.html
All class loading is managed by the OSGi container and you just need to run some commands to update things. I am not sure if this could work with your JSF application but it worths to take a look.