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<TITLE>Processing a HEAD Request in a Servlet (Java Developers Almanac Example)
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<h1>The Java Developers Almanac 1.4</h1>
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<A HREF="../javax.servlet/pkg.html">javax.servlet</A><font color="#666666" class="xsmall-font">
[11 examples]
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<B><A HREF="../javax.servlet/pkg.html#Requests">Requests</A></B><font color="#666666" class="xsmall-font">
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<h3>e1044. Processing a HEAD Request in a Servlet</h3>
By default, a HEAD request is automatically processed by the
<code>HttpServlet.doGet()</code> method using a modified response object that
simply counts and discards any characters written to the buffer. If
it is necessary to improve the performance of a servlet that is
frequently accessed with a HEAD request method, you can override the
<code>HttServlet.doHead()</code> method and implement a more efficient
algorithm. Typically, a <code>doHead()</code> implementation sets the content
length and type, as demonstrated by this example.
<P> Note: In the JWSDP 1.0, calling <code>resetBuffer()</code> does nothing
in a HEAD request. Therefore, if <code>resetBuffer()</code> is used during
servlet processing, a GET and HEAD request may return different
content lengths.
<pre> // See also <a href="../javax.servlet/com_mycompany_MyServlet.html" class="eglink"><b>e1035</b> The Quintessential Servlet</a>
// This method is called by the servlet container to process a HEAD request.
// There may be many threads calling this method simultaneously.
public void doHead(HttpServletRequest req, HttpServletResponse resp) throws IOException {
// Set the content length and type
resp.setContentLength(<font color="#0066ff"><i>123</i></font>);
resp.setContentType(<font color="#0066ff"><i>"text/html"</i></font>);
}
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<b>Related Examples</b></font></td>
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e1040. <a class="eglink" href="GetReqParam.html?l=rel">
Getting a Request Parameter in a Servlet
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e1041. <a class="eglink" href="NoMulti.html?l=rel">
Preventing Concurrent Requests to a Servlet
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e1042. <a class="eglink" href="GetReqUrl.html?l=rel">
Getting the Requesting URL in a Servlet
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e1043. <a class="eglink" href="GetHeaders.html?l=rel">
Getting a Request Header in a Servlet
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e1045. <a class="eglink" href="GetClientInfo.html?l=rel">
Getting the Client's Address in a Servlet
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