What are the built-in objects in jsp

jsp built-in objects include: 1. request; 2. response; 3. pageContext; 4. session; 5. application; 6. out; 7. config; 8. page. Detailed introduction: 1. request, HttpServletRequest object, represents the HTTP request sent by the client, through which the request parameters, header information, path information, etc. can be obtained; 2. response, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

JSP (JavaServer Pages) is a Java-based server-side programming technology that provides many built-in objects for processing requests, responses, session management, etc. The following are common built-in objects in JSP:

1. request: HttpServletRequest object, which represents the HTTP request sent by the client. You can use it to obtain request parameters, header information, path information, etc.

<%  
String param = request.getParameter("param");  
%>

2. response: HttpServletResponse object, representing the server’s HTTP response. You can use it to set the content type of the response, set cookies, redirect, etc.

<%  
response.setContentType("text/html");  
%>

3. pageContext: PageContext object provides access to other built-in objects and some control over the JSP page execution process.

<%  
String title = pageContext.getTitle();  
%>

4. session: HttpSession object, representing the user’s session. Data can be stored and retrieved within the session.

<%  
session.setAttribute("key", "value");  
String value = (String) session.getAttribute("key");  
%>

5. application: ServletContext object, representing the context of the Web application. Data can be stored application-wide and accessible to all users.

<%  
ServletContext context = getServletContext();  
context.setAttribute("key", "value");  
String value = (String) context.getAttribute("key");  
%>

6. out: JspWriter object, used to output content to the client. Can be used to output HTML, XML, etc.

<%  
out.println("Hello, World!");  
%>

7. config: ServletConfig object, representing the configuration information of the JSP page. Initialization parameters can be obtained through it.

<%  
ServletConfig config = getServletConfig();  
String param = config.getInitParameter("param");  
%>

8. Page: An object of Object type, representing the current JSP page itself. In a JSP page, you can use the page object to call methods of other Java classes.

These are common built-in objects in JSP. They provide rich functions and convenient interfaces, making it easier for JSP developers to handle HTTP requests, responses, and session management of Web applications.

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