What built-in objects and actions does JSP have?

Nine built-in objects and functions:

1. Request object: the client's request information is encapsulated in the request object, which can be used to understand the customer's requirements and then respond.
2. Response object: The response object contains information about the response to the customer request.
3. Session Object: the session object refers to a session between the client and the server. The session object starts when the client connects to a webapplication on the server until the client and the server are disconnected.
4. Out object: A Common Object for outputting content to the client
5. Page Object: The page object points to the current JSP page itself, a bit like this pointer in the class.
6. Application object: The Application Object shares data between users and stores global variables. It starts from the start of the server until the server is closed. During this period, this object will always exist. In this way, the object can be connected between users or between users, you can perform operations on the same attribute of this object. Operations on this object attribute anywhere will affect access by other users. The startup and shutdown of the server determine the life of the Application object.
7. Exception object: The exception object is an exception object. This object is generated when an exception occurs on a page during running. To apply this object to a JSP page, you must set iserrorpage to true; otherwise, compilation fails.
8. pagecontext object: The pagecontext object provides access to all objects and namespaces on the JSP page, that is, it can access the session on this page, you can also take a property value of the application where the page is located. It is equivalent to the aggregator of all functions on the page. Its Class Name is also called pagecontext.
9. config object: The Config object is used by the JSP Engine to transmit information to a servlet during initialization. This information includes the parameters used during servlet initialization (consisting of attribute names and attribute values) and server-related information (by passing a servletcontext object ).

 

JSP actions and functions:

JSP: include: Introduce a file when the page is requested.
JSP: usebean: Find or instantiate a JavaBean.
JSP: setproperty: Set attributes of JavaBean.
JSP: getproperty: outputs the attributes of a JavaBean.
JSP: Forward: Transfers requests to a new page.
JSP: Plugin: generate the object or embed tag for the Java Plug-in based on the browser type.