SPRINGMVC Controller Single Case problem

SPRINGMVC controller default is a singleton singleton, specifically can see the annotations scope can be seen at a glance.

There are two reasons for a single case:

1, for performance.

2, do not need many examples.

1, this does not have the nonsense, the single case does not need each time new, certainly fast.

2, do not need an instance will confuse many people, because spring MVC official did not explicitly say can not be many examples.

The reason why I don't need it here is to see how developers use it, and if you define a lot of attributes for the controller, then the Singleton will definitely have a competitive access.

Therefore, the Singleton is completely secure as long as the attribute is not defined in the controller. Here is an example of the following:

@Controller @requestmapping ("/demo")  Public class Multviewcontroller {    privatestaticint st = 0;      // of Static    Private int index = 0;          // non-static        @RequestMapping ("/test")    publicvoid  Test () {        System.out.println (St+ + + "|" + index++);}    }

The default singleton, as the number of requests increases:

0 | 0

1 | 1

2 | 2

3 | 3

4 | 4

...

Controller adds annotations:

@Scope (value = configurablebeanfactory.scope_prototype)

At this point, no matter how many requests, the result is:

0 | 0

1 | 0

2 | 0

3 | 0

4 | 0

...

It is easy to see from the above that the singleton is thread insecure and can result in the reuse of attributes.

Best Practices:

1. Do not define member variables in the controller.

2. If you have to define a non-static member variable, set it to a multiple-case mode by annotating @scope ("prototype")

SPRINGMVC Controller Single Case problem