Common instruction learning and JSP development instruction in jsp development

Common instruction learning and JSP development instruction in jsp development

(1) JSP commands

JSP Commands include page commands, include commands, and taglib commands.

(2) role of the page command

Syntax:

<% @ Page property name 1 = "property value 1"... property name n = "property value n" %>

1. import: import a Java class or package on the specified JSP page.

2. session: Restrict whether the session is available. The default value true indicates that the session is available, and fasle is unavailable.

3. isErrorPage: Specifies whether the JSP page is used to handle abnormal error pages. If it is set to true, exception is available. The default value is false.

4. errorPage = "URL": when a page exception occurs, it is the jump path.

5. contentType = "text/html; charset = UTF-8": the browser determines the document type based on the appearance.

6. pageEncoding: Specify the page encoding format.

7. autoFlush = "true | false": indicates whether the buffer is automatically cleared. The default value is true.

8. info = "text": describes information about the JSP page.

9. isThreadSafe = "false | true": whether to allow multithreading to use this page. The default value is true.

10. buffer = "8 KB": indicates whether the output stream has a cache. The default value is 8 KB.

11. Extends = "class": Specifies the parent class inherited by the Servlet generated on the JSP page.

(3) include commands to introduce files

<% @ Include file = "file path (either absolute or relative)" %>

Instance demo

<% @ Page import = "java. util. date "%> <% @ page language =" java "contentType =" text/html; charset = UTF-8 "pageEncoding =" UTF-8 "%> <! -- Embed HTML in JSP --> <! DOCTYPE html PUBLIC "-// W3C // dtd html 4.01 Transitional // EN" "https://www.w3.org/TR/html4/loose.dtd"> 
Output:

(3) taglib commands related to tags
Import package: jstl-1.2.jar, jstl-standard.jar
<% Taglib uri = "tagliburi" prefix = "tagPre" %> uri: indicates the location where the custom tag library is stored. prefix: distinguishes the tag names of different tag libraries.
Example:
<% @ Page language = "java" contentType = "text/html; charset = UTF-8 "pageEncoding =" UTF-8 "%> <% @ taglib uri =" https://java.sun.com/jstl/core_rt "prefix =" c "%> <! DOCTYPE html PUBLIC "-// W3C // dtd html 4.01 Transitional // EN" "https://www.w3.org/TR/html4/loose.dtd"> 
In the browser address bar, output: https: // localhost/Project/index. jsp? Username = "Kaina ":
Output: