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<div class="subTitle"><span class="packageLabelInType">Package</span> <a href="../../../javax/servlet/http/package-summary.html">javax.servlet.http</a></div>
<h2 title="Class HttpServlet" class="title">Class HttpServlet</h2>
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<div class="contentContainer">
<ul class="inheritance">
<li>java.lang.Object</li>
<li>
<ul class="inheritance">
<li><a href="../../../javax/servlet/GenericServlet.html" title="class in javax.servlet">javax.servlet.GenericServlet</a></li>
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<li>javax.servlet.http.HttpServlet</li>
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<dt>All Implemented Interfaces:</dt>
<dd><code>java.io.Serializable</code>, <code><a href="../../../javax/servlet/Servlet.html" title="interface in javax.servlet">Servlet</a></code>, <code><a href="../../../javax/servlet/ServletConfig.html" title="interface in javax.servlet">ServletConfig</a></code></dd>
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<pre>public abstract class <span class="typeNameLabel">HttpServlet</span>
extends <a href="../../../javax/servlet/GenericServlet.html" title="class in javax.servlet">GenericServlet</a></pre>
<div class="block">Provides an abstract class to be subclassed to create
an HTTP servlet suitable for a Web site. A subclass of
<code>HttpServlet</code> must override at least
one method, usually one of these:
<ul>
<li> <code>doGet</code>, if the servlet supports HTTP GET requests
<li> <code>doPost</code>, for HTTP POST requests
<li> <code>doPut</code>, for HTTP PUT requests
<li> <code>doDelete</code>, for HTTP DELETE requests
<li> <code>init</code> and <code>destroy</code>,
to manage resources that are held for the life of the servlet
<li> <code>getServletInfo</code>, which the servlet uses to
provide information about itself
</ul>
<p>There's almost no reason to override the <code>service</code>
method. <code>service</code> handles standard HTTP
requests by dispatching them to the handler methods
for each HTTP request type (the <code>do</code><i>Method</i>
methods listed above).
<p>Likewise, there's almost no reason to override the
<code>doOptions</code> and <code>doTrace</code> methods.
<p>Servlets typically run on multithreaded servers,
so be aware that a servlet must handle concurrent
requests and be careful to synchronize access to shared resources.
Shared resources include in-memory data such as
instance or class variables and external objects
such as files, database connections, and network
connections.
See the
<a href="http://java.sun.com/Series/Tutorial/java/threads/multithreaded.html">
Java Tutorial on Multithreaded Programming</a> for more
information on handling multiple threads in a Java program.</div>
<dl>
<dt><span class="seeLabel">See Also:</span></dt>
<dd><a href="../../../serialized-form.html#javax.servlet.http.HttpServlet">Serialized Form</a></dd>
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<th class="colFirst" scope="col">Constructor</th>
<th class="colLast" scope="col">Description</th>
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<tr class="altColor">
<th class="colConstructorName" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#HttpServlet--">HttpServlet</a></span>()</code></th>
<td class="colLast">
<div class="block">Does nothing, because this is an abstract class.</div>
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<caption><span id="t0" class="activeTableTab"><span>All Methods</span><span class="tabEnd"> </span></span><span id="t2" class="tableTab"><span><a href="javascript:show(2);">Instance Methods</a></span><span class="tabEnd"> </span></span><span id="t4" class="tableTab"><span><a href="javascript:show(8);">Concrete Methods</a></span><span class="tabEnd"> </span></span></caption>
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<th class="colFirst" scope="col">Modifier and Type</th>
<th class="colSecond" scope="col">Method</th>
<th class="colLast" scope="col">Description</th>
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<tr id="i0" class="altColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doDelete-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doDelete</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a DELETE request.</div>
</td>
</tr>
<tr id="i1" class="rowColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doGet-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doGet</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method) to
allow a servlet to handle a GET request.</div>
</td>
</tr>
<tr id="i2" class="altColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doHead-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doHead</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Receives an HTTP HEAD request from the protected
<code>service</code> method and handles the
request.</div>
</td>
</tr>
<tr id="i3" class="rowColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doOptions-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doOptions</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a OPTIONS request.</div>
</td>
</tr>
<tr id="i4" class="altColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doPost-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doPost</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a POST request.</div>
</td>
</tr>
<tr id="i5" class="rowColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doPut-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doPut</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a PUT request.</div>
</td>
</tr>
<tr id="i6" class="altColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#doTrace-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">doTrace</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a TRACE request.</div>
</td>
</tr>
<tr id="i7" class="rowColor">
<td class="colFirst"><code>protected long</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#getLastModified-javax.servlet.http.HttpServletRequest-">getLastModified</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req)</code></th>
<td class="colLast">
<div class="block">Returns the time the <code>HttpServletRequest</code>
object was last modified,
in milliseconds since midnight January 1, 1970 GMT.</div>
</td>
</tr>
<tr id="i8" class="altColor">
<td class="colFirst"><code>protected void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#service-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">service</a></span>​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)</code></th>
<td class="colLast">
<div class="block">Receives standard HTTP requests from the public
<code>service</code> method and dispatches
them to the <code>do</code><i>Method</i> methods defined in
this class.</div>
</td>
</tr>
<tr id="i9" class="rowColor">
<td class="colFirst"><code>void</code></td>
<th class="colSecond" scope="row"><code><span class="memberNameLink"><a href="../../../javax/servlet/http/HttpServlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-">service</a></span>​(<a href="../../../javax/servlet/ServletRequest.html" title="interface in javax.servlet">ServletRequest</a> req,
<a href="../../../javax/servlet/ServletResponse.html" title="interface in javax.servlet">ServletResponse</a> res)</code></th>
<td class="colLast">
<div class="block">Dispatches client requests to the protected
<code>service</code> method.</div>
</td>
</tr>
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<h3>Methods inherited from class javax.servlet.<a href="../../../javax/servlet/GenericServlet.html" title="class in javax.servlet">GenericServlet</a></h3>
<code><a href="../../../javax/servlet/GenericServlet.html#destroy--">destroy</a>, <a href="../../../javax/servlet/GenericServlet.html#getInitParameter-java.lang.String-">getInitParameter</a>, <a href="../../../javax/servlet/GenericServlet.html#getInitParameterNames--">getInitParameterNames</a>, <a href="../../../javax/servlet/GenericServlet.html#getServletConfig--">getServletConfig</a>, <a href="../../../javax/servlet/GenericServlet.html#getServletContext--">getServletContext</a>, <a href="../../../javax/servlet/GenericServlet.html#getServletInfo--">getServletInfo</a>, <a href="../../../javax/servlet/GenericServlet.html#getServletName--">getServletName</a>, <a href="../../../javax/servlet/GenericServlet.html#init--">init</a>, <a href="../../../javax/servlet/GenericServlet.html#init-javax.servlet.ServletConfig-">init</a>, <a href="../../../javax/servlet/GenericServlet.html#log-java.lang.String-">log</a>, <a href="../../../javax/servlet/GenericServlet.html#log-java.lang.String-java.lang.Throwable-">log</a></code></li>
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<h3>Methods inherited from class java.lang.Object</h3>
<code>clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait</code></li>
</ul>
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<a name="HttpServlet--">
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<h4>HttpServlet</h4>
<pre>public HttpServlet()</pre>
<div class="block">Does nothing, because this is an abstract class.</div>
</li>
</ul>
</li>
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<a name="doGet-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">
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<h4>doGet</h4>
<pre>protected void doGet​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method) to
allow a servlet to handle a GET request.
<p>Overriding this method to support a GET request also
automatically supports an HTTP HEAD request. A HEAD
request is a GET request that returns no body in the
response, only the request header fields.
<p>When overriding this method, read the request data,
write the response headers, get the response's writer or
output stream object, and finally, write the response data.
It's best to include content type and encoding. When using
a <code>PrintWriter</code> object to return the response,
set the content type before accessing the
<code>PrintWriter</code> object.
<p>The servlet container must write the headers before
committing the response, because in HTTP the headers must be sent
before the response body.
<p>Where possible, set the Content-Length header (with the
<a href="../../../javax/servlet/ServletResponse.html#setContentLength-int-"><code>ServletResponse.setContentLength(int)</code></a> method),
to allow the servlet container to use a persistent connection
to return its response to the client, improving performance.
The content length is automatically set if the entire response fits
inside the response buffer.
<p>When using HTTP 1.1 chunked encoding (which means that the response
has a Transfer-Encoding header), do not set the Content-Length header.
<p>The GET method should be safe, that is, without
any side effects for which users are held responsible.
For example, most form queries have no side effects.
If a client request is intended to change stored data,
the request should use some other HTTP method.
<p>The GET method should also be idempotent, meaning
that it can be safely repeated. Sometimes making a
method safe also makes it idempotent. For example,
repeating queries is both safe and idempotent, but
buying a product online or modifying data is neither
safe nor idempotent.
<p>If the request is incorrectly formatted, <code>doGet</code>
returns an HTTP "Bad Request" message.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - an <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client has made
of the servlet</dd>
<dd><code>resp</code> - an <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet sends
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error is
detected when the servlet handles
the GET request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the GET
could not be handled</dd>
<dt><span class="seeLabel">See Also:</span></dt>
<dd><a href="../../../javax/servlet/ServletResponse.html#setContentType-java.lang.String-"><code>ServletResponse.setContentType(java.lang.String)</code></a></dd>
</dl>
</li>
</ul>
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<h4>getLastModified</h4>
<pre>protected long getLastModified​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req)</pre>
<div class="block">Returns the time the <code>HttpServletRequest</code>
object was last modified,
in milliseconds since midnight January 1, 1970 GMT.
If the time is unknown, this method returns a negative
number (the default).
<p>Servlets that support HTTP GET requests and can quickly determine
their last modification time should override this method.
This makes browser and proxy caches work more effectively,
reducing the load on server and network resources.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <code>HttpServletRequest</code>
object that is sent to the servlet</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>a <code>long</code> integer specifying
the time the <code>HttpServletRequest</code>
object was last modified, in milliseconds
since midnight, January 1, 1970 GMT, or
-1 if the time is not known</dd>
</dl>
</li>
</ul>
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<h4>doHead</h4>
<pre>protected void doHead​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block"><p>Receives an HTTP HEAD request from the protected
<code>service</code> method and handles the
request.
The client sends a HEAD request when it wants
to see only the headers of a response, such as
Content-Type or Content-Length. The HTTP HEAD
method counts the output bytes in the response
to set the Content-Length header accurately.
<p>If you override this method, you can avoid computing
the response body and just set the response headers
directly to improve performance. Make sure that the
<code>doHead</code> method you write is both safe
and idempotent (that is, protects itself from being
called multiple times for one HTTP HEAD request).
<p>If the HTTP HEAD request is incorrectly formatted,
<code>doHead</code> returns an HTTP "Bad Request"
message.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the request object that is passed to the servlet</dd>
<dd><code>resp</code> - the response object that the servlet
uses to return the headers to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the HEAD
could not be handled</dd>
</dl>
</li>
</ul>
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<h4>doPost</h4>
<pre>protected void doPost​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a POST request.
The HTTP POST method allows the client to send
data of unlimited length to the Web server a single time
and is useful when posting information such as
credit card numbers.
<p>When overriding this method, read the request data,
write the response headers, get the response's writer or output
stream object, and finally, write the response data. It's best
to include content type and encoding. When using a
<code>PrintWriter</code> object to return the response, set the
content type before accessing the <code>PrintWriter</code> object.
<p>The servlet container must write the headers before committing the
response, because in HTTP the headers must be sent before the
response body.
<p>Where possible, set the Content-Length header (with the
<a href="../../../javax/servlet/ServletResponse.html#setContentLength-int-"><code>ServletResponse.setContentLength(int)</code></a> method),
to allow the servlet container to use a persistent connection
to return its response to the client, improving performance.
The content length is automatically set if the entire response fits
inside the response buffer.
<p>When using HTTP 1.1 chunked encoding (which means that the response
has a Transfer-Encoding header), do not set the Content-Length header.
<p>This method does not need to be either safe or idempotent.
Operations requested through POST can have side effects for
which the user can be held accountable, for example,
updating stored data or buying items online.
<p>If the HTTP POST request is incorrectly formatted,
<code>doPost</code> returns an HTTP "Bad Request" message.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - an <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client has made
of the servlet</dd>
<dd><code>resp</code> - an <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet sends
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error is
detected when the servlet handles
the request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the POST
could not be handled</dd>
<dt><span class="seeLabel">See Also:</span></dt>
<dd><a href="../../../javax/servlet/ServletOutputStream.html" title="class in javax.servlet"><code>ServletOutputStream</code></a>,
<a href="../../../javax/servlet/ServletResponse.html#setContentType-java.lang.String-"><code>ServletResponse.setContentType(java.lang.String)</code></a></dd>
</dl>
</li>
</ul>
<a name="doPut-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">
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<li class="blockList">
<h4>doPut</h4>
<pre>protected void doPut​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a PUT request.
The PUT operation allows a client to
place a file on the server and is similar to
sending a file by FTP.
<p>When overriding this method, leave intact
any content headers sent with the request (including
Content-Length, Content-Type, Content-Transfer-Encoding,
Content-Encoding, Content-Base, Content-Language, Content-Location,
Content-MD5, and Content-Range). If your method cannot
handle a content header, it must issue an error message
(HTTP 501 - Not Implemented) and discard the request.
For more information on HTTP 1.1, see RFC 2616
<a href="http://www.ietf.org/rfc/rfc2616.txt"></a>.
<p>This method does not need to be either safe or idempotent.
Operations that <code>doPut</code> performs can have side
effects for which the user can be held accountable. When using
this method, it may be useful to save a copy of the
affected URL in temporary storage.
<p>If the HTTP PUT request is incorrectly formatted,
<code>doPut</code> returns an HTTP "Bad Request" message.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>resp</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
PUT request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the PUT
cannot be handled</dd>
</dl>
</li>
</ul>
<a name="doDelete-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">
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<h4>doDelete</h4>
<pre>protected void doDelete​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a DELETE request.
The DELETE operation allows a client to remove a document
or Web page from the server.
<p>This method does not need to be either safe
or idempotent. Operations requested through
DELETE can have side effects for which users
can be held accountable. When using
this method, it may be useful to save a copy of the
affected URL in temporary storage.
<p>If the HTTP DELETE request is incorrectly formatted,
<code>doDelete</code> returns an HTTP "Bad Request"
message.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>resp</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
DELETE request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the
DELETE cannot be handled</dd>
</dl>
</li>
</ul>
<a name="doOptions-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">
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<li class="blockList">
<h4>doOptions</h4>
<pre>protected void doOptions​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a OPTIONS request.
The OPTIONS request determines which HTTP methods
the server supports and
returns an appropriate header. For example, if a servlet
overrides <code>doGet</code>, this method returns the
following header:
<p><code>Allow: GET, HEAD, TRACE, OPTIONS</code>
<p>There's no need to override this method unless the
servlet implements new HTTP methods, beyond those
implemented by HTTP 1.1.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>resp</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
OPTIONS request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the
OPTIONS cannot be handled</dd>
</dl>
</li>
</ul>
<a name="doTrace-javax.servlet.http.HttpServletRequest-javax.servlet.http.HttpServletResponse-">
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<h4>doTrace</h4>
<pre>protected void doTrace​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Called by the server (via the <code>service</code> method)
to allow a servlet to handle a TRACE request.
A TRACE returns the headers sent with the TRACE
request to the client, so that they can be used in
debugging. There's no need to override this method.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>resp</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
TRACE request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the request for the
TRACE cannot be handled</dd>
</dl>
</li>
</ul>
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<h4>service</h4>
<pre>protected void service​(<a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http">HttpServletRequest</a> req,
<a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http">HttpServletResponse</a> resp)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Receives standard HTTP requests from the public
<code>service</code> method and dispatches
them to the <code>do</code><i>Method</i> methods defined in
this class. This method is an HTTP-specific version of the
<a href="../../../javax/servlet/Servlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-"><code>Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)</code></a> method. There's no
need to override this method.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>resp</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
HTTP request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the HTTP request
cannot be handled</dd>
<dt><span class="seeLabel">See Also:</span></dt>
<dd><a href="../../../javax/servlet/Servlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-"><code>Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)</code></a></dd>
</dl>
</li>
</ul>
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<h4>service</h4>
<pre>public void service​(<a href="../../../javax/servlet/ServletRequest.html" title="interface in javax.servlet">ServletRequest</a> req,
<a href="../../../javax/servlet/ServletResponse.html" title="interface in javax.servlet">ServletResponse</a> res)
throws <a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a>,
java.io.IOException</pre>
<div class="block">Dispatches client requests to the protected
<code>service</code> method. There's no need to
override this method.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../javax/servlet/Servlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-">service</a></code> in interface <code><a href="../../../javax/servlet/Servlet.html" title="interface in javax.servlet">Servlet</a></code></dd>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../javax/servlet/GenericServlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-">service</a></code> in class <code><a href="../../../javax/servlet/GenericServlet.html" title="class in javax.servlet">GenericServlet</a></code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>req</code> - the <a href="../../../javax/servlet/http/HttpServletRequest.html" title="interface in javax.servlet.http"><code>HttpServletRequest</code></a> object that
contains the request the client made of
the servlet</dd>
<dd><code>res</code> - the <a href="../../../javax/servlet/http/HttpServletResponse.html" title="interface in javax.servlet.http"><code>HttpServletResponse</code></a> object that
contains the response the servlet returns
to the client</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code>java.io.IOException</code> - if an input or output error occurs
while the servlet is handling the
HTTP request</dd>
<dd><code><a href="../../../javax/servlet/ServletException.html" title="class in javax.servlet">ServletException</a></code> - if the HTTP request cannot
be handled</dd>
<dt><span class="seeLabel">See Also:</span></dt>
<dd><a href="../../../javax/servlet/Servlet.html#service-javax.servlet.ServletRequest-javax.servlet.ServletResponse-"><code>Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)</code></a></dd>
</dl>
</li>
</ul>
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