Struts2 Interceptor Depth Interpretation

Interceptors are the struts2 core, and many functions are implemented by interceptors.

I. Write a interceptor yourself



Write the interception in the Interceptor method





two. Configuring Interceptors in Struts2.xml

Write the <interceptor></interceptor> interceptor definition first, and then add the <interceptor-ref> reference after the action's result



Note：
The interceptor in the STRUTS2 is similar to the servlet filter, but the Struts2 interceptor can only be added in front of the action because it is configured in front of the action's result
The simple thing is that your interceptor inherits Abstactinterceptor.

Three. Method Interceptors (interception of specified methods)Methdfilterinterceptor

The above interceptor intercepts the Execute method in action, then how to intercept it by writing its own method.

1. Write a interceptor and then inherit the Methodfilterinterceptor class


2. Configure the method interceptor in Struts.xml to specify the interception method:





four. Using interceptors to verify user login

1). Write a login interceptor in addition to the login method to determine whether the user login

2). This interceptor is defined so that it should be used before each action method except for landing.

The above method return Action.login so in Struts.xml need to configure a gloabal-results name for login


Define a Interceptor-stack



Five. Executeandwaitinterceptor

When the HTTP request takes a long time, use this interceptor (on the one hand, let the user see the Waiting page, on the other hand, automatically refresh the request);
Configured as follows
1). Configure the Execandwait interceptor in the Struts.xml


2). The Handwriting wait.jsp



Six. The above interceptor interceptor can only intercept the action and cannot intercept the JSP page, so the servlet filter is required.

1). Define a filter of your own



2). Configure in Web. xml



--for verification, etc. operations





Reprinted from: http://blog.sina.com.cn/s/blog_aaa756740101hudd.html