Java Reference
In-Depth Information
If you specify a context-relative or page-relative URL for the value attribute, <c:url> prepends
the context path of the web application to the URL; for example, if the context path of the web
application is /bookWeb/books , the <c:url> action <c:url value='/book.jsp'/> will result
in url:/bookWeb/books/book.jsp .
The <c:redirect>Action
The <c:redirect> action sends an HTTP redirect to the client, redirecting the browser to an alternate
URL. The <c:redirect> action provides the URL rewriting with a redirect.
Here's the syntax without body content:
<c:redirect url="value" [context="context"]/>
Here's the syntax with body content to specify query string parameters:
<c:redirect url="value" [context="context"]>
<c:param> subtags
</c:redirect>
The <c:redirect> action has two attributes: the URL that will be used to redirect to and an optional context.
The attributes of <c:redirect> are listed in the Table 3-23 .
Table 3-23. <c:redirect> Attributes
Name
Type
Description
url
String
The URL of the resource to redirect to
context
String
The name of the context when redirecting to a relative URL resource that belongs to
a foreign context
The URL, relative or absolute, follows the same URL rewriting rules as <c:url> . Listing 3-55
illustrates redirecting to an external resource, which is an absolute URL.
Listing 3-55. Using <c:redirect>
<c:redirect url=" http://www.yourbookstore.com " />
You can redirect to a resource in a foreign context using the context attribute. The URL specified
must start with a / as a context-relative URL, and as defined, the context name must also start with
a / . Listing 3-56 illustrates redirecting to a foreign resource in a foreign context.
Listing 3-56. redirecting to a foreign resource in a foreign context.
<c:redirect url="/foreignresource.html" context="/foreigncontext" />
In this chapter, we have looked at the nuts and bolts of the Java EE machine in the web tier: the web
components (servlets and JSP), the feature-rich Expression Language, and the ready-to-use custom
actions (JSTL). Now we'll talk about best-practice solutions using patterns.
 
 
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