javax.servlet
接口 ServletRequestAttributeListener

所有超级接口：

EventListener

public interface ServletRequestAttributeListener
extends EventListener

Interface for receiving notification events about ServletRequest attribute changes.

Notifications will be generated while the request is within the scope of the web application. A ServletRequest is defined as coming into scope of a web application when it is about to enter the first servlet or filter of the web application, and as going out of scope when it exits the last servlet or the first filter in the chain.

In order to receive these notification events, the implementation class must be either declared in the deployment descriptor of the web application, annotated with WebListener, or registered via one of the addListener methods defined on ServletContext.

The order in which implementations of this interface are invoked is unspecified.

从以下版本开始：

Servlet 2.4

方法摘要

void	attributeAdded(ServletRequestAttributeEvent srae) Receives notification that an attribute has been added to the ServletRequest.
void	attributeRemoved(ServletRequestAttributeEvent srae) Receives notification that an attribute has been removed from the ServletRequest.
void	attributeReplaced(ServletRequestAttributeEvent srae) Receives notification that an attribute has been replaced on the ServletRequest.

方法详细信息

attributeAdded

void attributeAdded(ServletRequestAttributeEvent srae)

Receives notification that an attribute has been added to the ServletRequest.

参数：

srae - the ServletRequestAttributeEvent containing the ServletRequest and the name and value of the attribute that was added

attributeRemoved

void attributeRemoved(ServletRequestAttributeEvent srae)

Receives notification that an attribute has been removed from the ServletRequest.

参数：

srae - the ServletRequestAttributeEvent containing the ServletRequest and the name and value of the attribute that was removed

attributeReplaced

void attributeReplaced(ServletRequestAttributeEvent srae)

Receives notification that an attribute has been replaced on the ServletRequest.

参数：

srae - the ServletRequestAttributeEvent containing the ServletRequest and the name and (old) value of the attribute that was replaced