JSP Tutorials - Herong's Tutorial Examples - v5.11, by Herong Yang
Using JavaBean Objects in Scripting Elements
This section provides a tutorial example on how to use JavaBean objects in scripting elements. A JavaBean is really just Java class object, which can be used in any scripting elements.
As I mentioned in the previous section, JavaBean is just a normal Java object with some special methods. Once a JavaBean is created, we should be able to use it as Java object in any scripting elements.
Here is a sample page to show you how to use a JavaBean as a Java object. It is using the same JavaBean class, herong.DemoBean, as provided in the previous section.
<?xml version="1.0"?> <jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.3"> <!-- BeanAsObject.jspx - Copyright (c) 2006 HerongYang.com. All Rights Reserved. --> <jsp:directive.page contentType="text/html"/> <html><body> <jsp:useBean id="b" class="herong.DemoBean"/> <jsp:setProperty name="b" property="author" value="Someone"/> Line 11: author = <jsp:expression>b.getAuthor()</jsp:expression><br/> <jsp:scriptlet><![CDATA[b.setTotal(10);]]></jsp:scriptlet> Line 12: total = <jsp:getProperty name="b" property="total"/><br/> <jsp:scriptlet><![CDATA[b.setSize(15);]]></jsp:scriptlet> Line 13: size = <jsp:getProperty name="b" property="size"/><br/> Line 14: size = <jsp:scriptlet><![CDATA[out.println(b.getSize());]]></jsp:scriptlet> <br/> <jsp:scriptlet><![CDATA[ Object o = pageContext.findAttribute("b"); String s = ((herong.DemoBean)o).getSize(); out.println("Line 15: size = "+s); ]]></jsp:scriptlet><br/> </body></html> </jsp:root>
Open this JSP page with IE, you will get:
Line 11: author = Someone Line 12: total = int: 10 Line 13: size = int: 15 Line 14: size = int: 15 Line 15: size = int: 15
Note that:
Table of Contents
JSP (JavaServer Pages) Overview
Tomcat Installation on Windows Systems
Syntax of JSP Pages and JSP Documents
►JavaBean Objects and "useBean" Action Elements
"jsp:useBean" Requires Fully Qualified Class Name
Servlet Class Converted from UseBean.jspx
Setting and Getting JavaBean's Properties
►Using JavaBean Objects in Scripting Elements
Using Java Objects as JavaBeans
getProperty() Error on Tomcat 7
Refreshing Loaded JavaBean Classes
Importing Unnamed Package Class Error
Using JavaBean without Import Element Error
Creating JavaBean Classes in Named Packages
"NoClassDefFoundError" Exception
Managing HTTP Response Header Lines
Non-ASCII Characters Support in JSP Pages
Overview of JSTL (JSP Standard Tag Libraries)
Multiple Tags Working Together
Using Tomcat on CentOS Systems
Connecting to SQL Server from Servlet