I have one controller per module in my spring application and the output from first controller decides the next controller to be called.All the controllers are configured in workflow.xml file.
I am not able to understand how to call the workflow.xml from the application and the result from one controller to another passes on.
Related
as i understand MVC pattern as post MVC question
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the Model is the part of the code that knows things
the View is the part of the code that shows the things the Model
knows
the Controller is the part of the code that gets commands from the
user and tells the View what to show and the Model what to know.
in spring-mvc we have DispatcherServlet which acts as controller gets command from client, also we have developer written controllers which serve commands and resolve the view and prepare Model for that view
in spring-mvc what exactly acts as controller DispatcherServlet or developer written controllers
Your #Controller annotated classes are your controllers. Think of the DispatcherServlet - as the name tells you - as dispatcher to your controllers.This is the same approach other MVC frameworks also choose (like Struts 2).
I am using Struts 2 v 2.3.16.3 with tomcat 6.
A user will click on an action which finds an object by id and the page displays it. I have encountered a sporadic bug where the user will all of a sudden get the id of another lookup from another user on another machine. So effectively they are both calling the same action but passing different id to the request, but both end up viewing the same id.
This is obviously disastrous, and the data is totally corrupted as both users think they are editing a different record. Any ideas how make sure session/request activity is kept secure to each session?
I am also using spring and am using the #Transactional annotation in my Service layer, which returns the objects from the DAO. Is there something I need to do with this annotation to make it secure for each session ?
I am using org.springframework.orm.hibernate3.HibernateTransactionManager
Classic Thread-UnSafe problem.
Since you nominated Spring, my first guess is that you have not specified the right scope for your action beans in Spring xml configuration.
Be sure you are using scope="prototype" because otherwise the default scope of Spring is Singleton, and you don't want a single(ton) instance of an Action, that would not be ThreadLocal (and hence ThreadSafe) anymore.
If it is not that, it could be something on an Interceptor (that, differently from an action, is not Thread Safe), or you are using something static (in your Business / DAO layer, or in the Action itself) that should be not.
Usually Struts 2 action instances will get create on the request. I mean per every request new action instance will get create. But if I integrate with Spring then there will be only one action instance will get create (I am not sure correct me if I am wrong).
So in this case what is if I have instance variables in the action class?
First user here will set that instance with some instance variables and second user may set there something. How it will behave at this time?
More clarification: Instance variable means, in Struts 2, action forms won't be there so, your action itself work as a form to get the request parameters. First user enters something and second user enters something and both are setting to one instance action.
If your actions are managed by Struts container, then Struts is creating them in the default scope.
If your actions are managed by Spring container, then you need to define the scope of the action beans, because Spring by default uses singleton scope.
If you don't want to share your action beans between user's requests you should define the corresponding scope.
You can use prototype scope, which means a new instance is returned by the Spring each time Struts is being built an action instance.
I am asking this question because of the following reasons:
Usually struts 2 action instances will get create on the request. I mean per every request new action instance will get create. But if I integrate with spring then there will be only one action instance will get create (I am not sure correct me if i am wrong). So in this case what is if I have instance variables in the action class. First user he will set that instance with some instance variables and second user may set the something.
How it will behave at this time.
More clarification: Instance variable means, in struts 2, action forms wont be there so, your action itself work as a form to get the request parameters. First user enters something and second user enters something and both are setting to one instance action.
By default Spring will create a singleton instance of your action class. In that case, depending on how your action classes are written there might be such a danger.
But you can also specify that a bean be created prototypically (scope="prototype") so that a new instance of the class is created with each request.
First, If you integrated struts2 with spring, normally, the action instances are managed by spring container! this is supported by struts2 spring plugin: https://struts.apache.org/release/2.3.x/docs/spring-plugin.html
Second, as the plugin doc mentioned, by default, the action bean's scope is request, this is up to the struts2, but you can change yuor action scope to other type,i.e. session,application,etc.
I have a quick question about how to use the Spring MVC.
I just started with it and i was used to have pages that always had their data loaded calling some controller that you setted ON THE PAGE.. calling some methods on controllers to load objects at the page at load time.
Is it the same in Spring MVC? Cuz what im seeing so far is that if you want to load a page with data, you always have to use a modelandview object which is loaded by a method that you must call before... and them you return the modelandview object with its destination to the view that you want.
What im trying to know is if there is a way that the page requests some data from the controller before it gets loaded... automatically...
Dont know if im making my self clear... thanks anyway for the help!
in spring mvc, using Controllers, it is always Request->Controller(populates model and chooses view)->Response.
you could use ajax to load data from any resource (even Controllers) or jsp:useBean to explicitly call some business logic or jsp:include to include a certain fragment or a custom jsp tag.
I also face the same situation.
check the below link for getting the data from the controller before view(JSP) load.
how to load the data into index page