Currently we have a PropertyOverrideConfigurer from Spring that is used to override some values of our configuration, the configuration is then used in Spring and Seam. Now I'd like to create an OverrideConfigurer that uses a DB connection managed by Seam to inject the overridden values into the configuration.
Is there already such a class or am I on my own?
I see that there is no support from Spring. Probably you need to do it yourself. This link may help you to confirm that you need do it yourself.
Related
I learning Spring boot and found that in some examples use the same properties with the prefix spring.jpa.properties while other do it without prefix.
For instance:
The article explains second level cahche https://www.baeldung.com/hibernate-second-level-cache and autor shows example of needed properties ( example on autor's gitHub):
hibernate.cache.use_second_level_cache=true
hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory
But it did not work for me, and I spent few hours loking for the reason, but then i noticed, someone use prefix spring.jpa.properties. to get it working (Exact moment from video lesson):
spring.jpa.properties.hibernate.cache.use_second_level_cache=true
spring.jpa.properties.hibernate.cache.region.factory_class=org.hibernate.cache.ehcache.EhCacheRegionFactory
Which perfectly worked for me.
So my questions are:
why are they working in different way?
how to understand which properties in which cases requires this prefix?
is it probably something related to my project settings OR Spring Boot version?
any other suggestions are appreciated :)
Thank you in advance!
There are a couple of things in play here. First the tutorial you use is using plain Spring not Spring Boot. Which means a manually configured EntityManagerFactory on which you directly can set the provider specific properties. Like hibernate.cache.use_second_level_cache.
As you decided to use Spring Boot you don't have a manually configured EntityManagerFactory (although you could!). Which means you are using an autoconfigured EntityManagerFactory. Properties for this reside in the spring.jpa namespace for properties.
As it isn't feasible to specify properties for each and every extension for Hibernate (or other JPA providers) only some commonly used ones are exposed like spring.jpa.generate-ddl and a few provider specific ones in the spring.jpa.hibernate namespace. However to set all the other properties in an autoconfigured way there needed to be something else. Hence the spring.jpa.properties prefix. Anything specified in there will be passed on as is (without the said prefix ofcourse) to the EntityManagerFactory for configuration.
I need a why to change the JPA catalog element in my java class? We have many database environments which we need to be able to deploy our application too. Example: In your dev environment we have a database for new development, and production support. All database live on the same server so we have the following database names: am_web_dd and am_web_ps. So we need to be able to change the catalog at build time or start up time. We've thought of using Maven to do a search and replace during build but I was wondering if there is a way of doing this with a parameter?
Here is one of our #RooJpaActiceRecord statements:
#RooJpaActiveRecord(catalog = "am_web_t4", schema = "dbo", table = "user_t")
I would like to be able to make catalog a parameter. Is this possible? if not what would be the best approach?
Thank you for your time!
I know it is possible from a JPA standpoint, but I don't think you will be able to using straight Roo. This might help.
There may also be a way to use a Java Configuration object in Spring to build your JPA Entity Manager. I think that's were you want to set it.
The approach you suggest of making catalog dynamic would be suitable if you wanted to let the user choose/change the schema on demand, however, it looks like this is not your requirements, so I would steer away from this path as it more difficult than you need.
You can use spring profiles to define different database connections and use an environment variable to define which one is active. Spring profiles can be set in XML or java configuration classes.
I am a Struts2 and Spring newbie and looking for some insight. When we load a web application we would typically want to cache some default look up data. e.g. if we wanted to store states or other data that does not change frequently and add it to the application context where we can access it across the application. What is the best way to realize this in a Struts2 application integrated with Spring? I read a bit about annotating with #PostConstruct which means I define my own class/method that would get a handle to the context by calling ServletActionContext.getServletContext() and then use setAttribute to add something. Is that a good way of going about things or is there a better option? Or would simply implementing a ServletContextListener be ideal?
Thanks for any input.
If you want to use the ServletContext, use Spring's ServletContextAware interface and then use an #PostConstruct or afterPropertiesSet method to add items to the servlet context.
This is simpler to use than the listener and integrates seamlessly with Spring, giving you access to properties files declared in Spring and any other beans.
Say I have a file with each line depicting a different command (but of the same kind), which I want to read out and check and run and maybe do other operations such as merging, comparing and most importantly, store the commands into database.
To do that, I create the Command Class, and new a new Command object while reading each line of the file. Now the problem is, a Command object need to make use of, say a Spring bean which provides database access. As a result, I have to pass in that bean as a constructor argument of the Command class, which is very ugly, which doesn't seem to be the "Spring way"...
and I don't want to use ApplicationContextAware to make my class coupled to the Spring context.
Is there a best practice for this situation?
I very new to Spring and I know it might be a dumb question ...
I would create a CommandFactory that is coupled with spring and use that in your consumer instead. If the factory implements an interface you are not coupling yourself in the consumer and you don't close your possibilities of using a different -non spring coupled- one at a later point (e.g. testing).
In this case I think it is the best way to make the classes created by new Spring Beans.
Therefor annotate them with #Configurable, enable AspectJ, and read the Spring Reference Chapter 7.8.1 Using AspectJ to dependency inject domain objects with Spring
I have a spring based web-application that needs to get data from ActiveMQ via a JMX connection.
I am using MBeanServerConnectionFactoryBean (in Spring) to get various MBean attributes from ActiveMQ.
I have only one MBeanServerConnectionFactoryBean as a member variable, which is used to get the data. If multiple requests/threads come concurrently will there be any issues? Will there be any race conditions?
Please suggest the best way to keep the code thread-safe.
Spring FactoryBean objects are not intended to be used directly from your code, they're supposed to be used in your Spring config. As such, they are designed to be executed once and once only.
If you want to use them, including MBeanServerConnectionFactoryBean, then you need to create them, configure them, use them and discard them each and every time you want to get the object they create. They are most definitely not thread-safe.
Better yet, do it as the design intended and use them in your Spring config.