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<TITLE>Passing Parameters to Another JSP Page (Java Developers Almanac Example)
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<h1>The Java Developers Almanac 1.4</h1>
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<B><A HREF="../javax.servlet.jsp/pkg.html#Java Server Pages Input">Java Server Pages Input</A></B><font color="#666666" class="xsmall-font">
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<h3>e1055. Passing Parameters to Another JSP Page</h3>
An <code>include</code> action (see <a href="../javax.servlet.jsp/include.jsp.html" class="eglink"><b>e1054</b> Including a File in a JSP Page</a>)
executes the included JSP page and appends the generated output onto
its own output stream. Request parameters parsed from the URL's query
string are available not only to the main JSP page but to all included
JSP pages as well. It is possible to temporarily override a request
parameter or to temporarily introduce a new request parameter when
calling a JSP page. This is done by using the <code>jsp:param</code> action.
<P> In this example, <code>param1</code> is specified in the query string
and is automatically made available to the callee JSP page.
<code>param2</code> is also specified in the query string but is overridden by
the caller. Notice that <code>param2</code> reverts to its original value
after the call. <code>param3</code> is a new request parameter created by the
caller. Notice that <code>param3</code> is only available to the callee and
when the callee returns, <code>param3</code> no longer exists.
Here is the caller JSP page:
<pre> <html>
<head></head>
<body>
<jsp:include page=<font color="#0066ff"><i>"callee.jsp"</i></font> />
<jsp:param name=<font color="#0066ff"><i>"param2"</i></font> value=<font color="#0066ff"><i>"value2"</i></font> />
<jsp:param name=<font color="#0066ff"><i>"param3"</i></font> value=<font color="#0066ff"><i>"value3"</i></font> />
</jsp:include>
Caller:
param1: <%= request.getParameter(<font color="#0066ff"><i>"param1"</i></font>) %>
param2: <%= request.getParameter(<font color="#0066ff"><i>"param2"</i></font>) %>
param3: <%= request.getParameter(<font color="#0066ff"><i>"param3"</i></font>) %>
</body>
</html>
</pre>
Here is the JSP page being called:
<pre> Callee:
param1: <%= request.getParameter(<font color="#0066ff"><i>"param1"</i></font>) %>
param2: <%= request.getParameter(<font color="#0066ff"><i>"param2"</i></font>) %>
param3: <%= request.getParameter(<font color="#0066ff"><i>"param3"</i></font>) %>
</pre>
If the example is called with the URL:
<pre> http://hostname.com?param1=a&param2=b
</pre>
the output would be:
<pre> Callee:
param1: a
param2: value2
param3: value3
Caller:
param1: a
param2: b
param3: null
</pre>
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<b>Related Examples</b></font></td>
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e1053. <a class="eglink" href="getparam.html?l=rel">
Getting a Request Parameter in a JSP Page
</a>
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e1054. <a class="eglink" href="include.jsp.html?l=rel">
Including a File in a JSP Page
</a>
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e1056. <a class="eglink" href="usebean.jsp.html?l=rel">
Using a Bean in a JSP Page
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See also:
<a class="eglink" href="/egs/javax.servlet.jsp/pkg.html?l=rel#Java%20Server%20Pages">
Java Server Pages
</a>
<a class="eglink" href="/egs/javax.servlet.jsp/pkg.html?l=rel#Java%20Server%20Pages%20Headers">
Java Server Pages Headers
</a>
<a class="eglink" href="/egs/javax.servlet.jsp/pkg.html?l=rel#Java%20Server%20Pages%20Output">
Java Server Pages Output
</a>
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