Interceptor

Struts2 Framework Interceptors:

Struts 2 framework provides a good list of out-of-the-box interceptors that come preconfigured and ready to use. Few of the important interceptors are listed below:

SN Interceptor & Description
1 alias
Allows parameters to have different name aliases across requests.
2 checkbox
Assists in managing check boxes by adding a parameter value of false for check boxes that are not checked.
3 conversionError
Places error information from converting strings to parameter types into the action's field errors.
4 createSession
Automatically creates an HTTP session if one does not already exist.
5 debugging
Provides several different debugging screens to the developer.
6 execAndWait
Sends the user to an intermediary waiting page while the action executes in the background.
7 exception
Maps exceptions that are thrown from an action to a result, allowing automatic exception handling via redirection.
8 fileUpload
Facilitates easy file uploading.
9 i18n
Keeps track of the selected locale during a user's session.
10 logger
Provides simple logging by outputting the name of the action being executed.
11 params
Sets the request parameters on the action.
12 prepare
This is typically used to do pre-processing work, such as setup database connections.
13 profile
Allows simple profiling information to be logged for actions.
14 scope
Stores and retrieves the action's state in the session or application scope.
15 ServletConfig
Provides the action with access to various servlet-based information.
16 timer
Provides simple profiling information in the form of how long the action takes to execute.
17 token
Checks the action for a valid token to prevent duplicate formsubmission.
18 validation
Provides validation support for actions