Creating and Using a JavaBeans Component

To declare that your JSP page will use a JavaBeans component, you use a jsp:useBean element. There are two forms:

<jsp:useBean id="beanName"
    class="fully-qualified-classname" scope="scope"/>

and

<jsp:useBean id="beanName"
    class="fully-qualified-classname" scope="scope">
    <jsp:setProperty .../>
</jsp:useBean>

The second form is used when you want to include jsp:setProperty statements, described in the next section, for initializing bean properties.

The jsp:useBean element declares that the page will use a bean that is stored within and is accessible from the specified scope, which can be application, session, request, or page. If no such bean exists, the statement creates the bean and stores it as an attribute of the scope object (see Using Scope Objects). The value of the id attribute determines the name of the bean in the scope and the identifier used to reference the bean in EL expressions, other JSP elements, and scripting expressions (see Chapter 9, Scripting in JSP Pages). The value supplied for the class attribute must be a fully qualified class name. Note that beans cannot be in the unnamed package. Thus the format of the value must be package-name.class-name.

The following element creates an instance of mypkg.myLocales if none exists, stores it as an attribute of the application scope, and makes the bean available throughout the application by the identifier locales:

<jsp:useBean id="locales" scope="application"
    class="mypkg.MyLocales"/>