I have a question that, i have a spring-mvc based project which is accessible by multiple user. My question is that when more than one user access that application then for each user there is separate controller class object or all user access the same controller class object.
There will be multiple controller instances for different requests.
Please read:
http://docs.spring.io/spring-framework/docs/2.5.x/reference/mvc.html
Related answer:
How does Spring MVC handle multiple users
If the controller is a bean (which is the usual case) then the default is one bean per Spring container context.
If you set the controller/bean to scope=prototype then you would get a new instance from the factory each time.
Related
I have a callable type class. It is a annotated with #component. I would like to create multiple instances of the callable class. To do so, I am using the application context. The problem is it simply does not work.
Refer Bean scope you want to use:
https://docs.spring.io/spring-framework/docs/3.0.0.M3/reference/html/ch04s04.html#:~:text=2%20The%20prototype%20scope,method%20call%20on%20the%20container).
singleton - once for each IoC container, your application context
prototype- multiple beans for multiple object instance
request - in case of web aware app context, each bean to a particular HTTP request, and new instance for another
session- for each HTTP session.
global session - as what name says.
depending on your use select scope as well explained by #BeUndead.
Given having next classes:
XRepository with declared a constructor with 1 argument (simple one,
not autowired), it has some autowired fields.
XService that uses XRepository as autowired.
XProcessor uses XService as autowired.
So I have to init XProcessor on runtime for specific value that will be used in XRepository constructor. On different calls I will have different arguments, so the injection should be on runtime.
Any idea how to achieve that using code configuration or annotations?
Remember that Spring needs to inject all the constructor parameters of Spring managed beans.
I believe you have two options:
Parse your URL info in controller and pass it through parameters down to persistence layer. This would be my preferred mechanism. You can create special DTO for passing various information down and keep your method signatures concise.
Your situation can alos be solved with request scope bean. You will
create one bean like this:
#Component
#Scope("request")
public class {
private String urlPart;
}
And you would autowire this component into XProcessor and
XRepository. Each request to your application will create new
instance of XRequestContext and you will parse your info in
XProcessor and store it into XRequestContext.
In XRepository you will use instance of XRequestContext to
retrieve information you stored in XProcessor.
You can read about request scope in Spring docs. It is like
ThreadLocal per request thread.
I was creating my first application using Apache wicket and am stuck on a problem. After the user logs in through the authentication method I have a new session which is created for that user. Now if I wanted to have data stored for just that user how would I use bean to implement that?
At the moment i created an interface and a class with get and set methods for the variables i wanted stored and created a bean such as <bean id="springApplicationContext" class="com..util.SpringApplicationContext"/> but what happens is the data gets overwritten but when i change the scope to "session" everyone has the same data in the bean still.
Thanks
The correct way is to use Session scoped Spring bean. There must be some error in your config if the data is visible to all users.
Using Spring has nothing to do with Wicket though!
Alternative approach is to store your data in Wicket's Session class.
Override MyApplication#newSession() method and return MySession class. The instance of MySession will be stored as an attribute in the HTTP session by Wicket. You can put any member fields inside MySession, e.g.;
public class MySession extends WebSession {
...
private MyBean myBean;
// setter and getter
...
}
Then in your Wicket code use it with: MySession.get().getMyBean().setSome(thing);
Can Spring MVC paths be set as Java config, rather than using annotations on the controller?
I want to re-use one controller class under different path mappings, and have each instance wired with different service implementations.
For example, the API will look a bit like this:
PUT /mysql/some_key/some_value
GET /mysql/some_key
DELETE /mysql/some_key
PUT /oracle/some_key/some_value
GET /oracle/some_key
DELETE /oracle/some_key
So there'd be one instance of the controller wired with a MySqlCrudService and one instance of the controller with an OracleCrudService.
How would one configure this? The controller could have the methods annotated (eg #RequestMapping(method=RequestMethod.PUT, value="/{key}/{value}"), but when constructing the controller in Java config I'd need to specify the class-level path mapping.
I have several controllers in a spring mvc application. They are regular beans that inherit from MultiActionController. They also have a custom MethodNameResolver that inspects a certain request parameter.
Now I am trying to use a new controller - a pojo with #Controller annotation. I am using #RequestMapping to resolve methods.
I am not sure if I understand this correctly, but as explained here in the spring reference, it is possible to use #RequestMapping with various filters (e.g. GET vs POST) without specifying a path, and then if a url applies to several methods then Spring falls back to InternalPathMethodNameResolver to decide which method to invoke.
How can I tell Spring to fall back to my custom MethodNameResolver? Is it enough to inject the resolver to my pojo controller?
(my controller doesn't inherit from any Spring specific class)
I guess you need to declare AnnotationMethodHandlerAdapter bean and set its methodNameResolver property.