JSP-built-in object

Built-in object : Tomcat helped us instantiate it.

Built-in object	Class
Pagecontext	Javax. servlet. jsp. pagecontext
Request	Javax. servlet. http. httpservletrequest
Response	Javax. servlet. http. httpservletresponse
Session	Javax. servlet. http. httpsession
Config	Javax. servlet. servletconfig
Application	Javax. servlet. servletcontext
Out	Javax. servlet. jsp. jspwriter
Page	Java. Lang. Object
Exception	Java. Lang. throwable

 

1,Built-in object(9)

There are four types: (1) servlet-related hidden objects: Page, config; (2) hidden objects related to input/output: Out, request, and response; (3) for containers, data is saved to the containers: Session, application, and pagecontext;

(4) hidden objects related to error: exception;

 

2,Two Methods of attribute(Set and obtain attributes)

-Set attributes: public abstract void setattribute (Java. Lang. string name, java. Lang. Object attribute)

-Get attribute: public abstractJava. Lang. ObjectGetattribute (Java. Lang. string name)

 

3,Storage range of the four attributes (The attribute storage range refers to the number of pages that a built-in object can save and continue to use.)

Page, request, session, Application

(1) page range (pagecontext): valid for one page. redirection is invalid.

(2) request range: valid for server redirect and invalid for client redirect.

(3) Session range: The jump is valid and the new browser is invalid.

(4) Application Scope: valid for all users and invalid for restarting the server.

 

 

Http://blog.csdn.net/xiazdong/article/details/6848382

Http://blog.sina.com.cn/s/blog_5329b1d80100ajm7.html