servletcontext.html

j2ee帮助文档软件设计/软件工程 文件格式

getRealPath</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>getRealPath</B>(<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;path)</PRE>
<DL>
<DD>Returns a <code>String</code> containing the real path 
 for a given virtual path. For example, the path "/index.html"
 returns the absolute file path on the server's filesystem would be
 served by a request for "http://host/contextPath/index.html",
 where contextPath is the context path of this ServletContext..

 <p>The real path returned will be in a form
 appropriate to the computer and operating system on
 which the servlet container is running, including the
 proper path separators. This method returns <code>null</code>
 if the servlet container cannot translate the virtual path
 to a real path for any reason (such as when the content is
 being made available from a <code>.war</code> archive).
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>path</CODE> - a <code>String</code> specifying a virtual path
<DT><B>Returns:</B><DD>a <code>String</code> specifying the real path,
                  or null if the translation cannot be performed</DL>
</DD>
</DL>
<HR>

<A NAME="getServerInfo()"><!-- --></A><H3>
getServerInfo</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>getServerInfo</B>()</PRE>
<DL>
<DD>Returns the name and version of the servlet container on which
 the servlet is running. 

 <p>The form of the returned string is 
 <i>servername</i>/<i>versionnumber</i>.
 For example, the JavaServer Web Development Kit may return the string
 <code>JavaServer Web Dev Kit/1.0</code>.

 <p>The servlet container may return other optional information 
 after the primary string in parentheses, for example,
 <code>JavaServer Web Dev Kit/1.0 (JDK 1.1.6; Windows NT 4.0 x86)</code>.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>a <code>String</code> containing at least the 
                        servlet container name and version number</DL>
</DD>
</DL>
<HR>

<A NAME="getInitParameter(java.lang.String)"><!-- --></A><H3>
getInitParameter</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>getInitParameter</B>(<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;name)</PRE>
<DL>
<DD>Returns a <code>String</code> containing the value of the named
 context-wide initialization parameter, or <code>null</code> if the 
 parameter does not exist.

 <p>This method can make available configuration information useful
 to an entire "web application".  For example, it can provide a 
 webmaster's email address or the name of a system that holds 
 critical data.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - a <code>String</code> containing the name of the
                  parameter whose value is requested
<DT><B>Returns:</B><DD>a <code>String</code> containing at least the 
                        servlet container name and version number<DT><B>See Also:</B><DD><A HREF="../../javax/servlet/ServletConfig.html#getInitParameter(java.lang.String)"><CODE>ServletConfig.getInitParameter(java.lang.String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getInitParameterNames()"><!-- --></A><H3>
getInitParameterNames</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/util/Enumeration.html" title="class or interface in java.util">Enumeration</A> <B>getInitParameterNames</B>()</PRE>
<DL>
<DD>Returns the names of the context's initialization parameters as an
 <code>Enumeration</code> of <code>String</code> objects, or an
 empty <code>Enumeration</code> if the context has no initialization
 parameters.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>an <code>Enumeration</code> of <code>String</code> 
                  objects containing the names of the context's
                  initialization parameters<DT><B>See Also:</B><DD><A HREF="../../javax/servlet/ServletConfig.html#getInitParameter(java.lang.String)"><CODE>ServletConfig.getInitParameter(java.lang.String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getAttribute(java.lang.String)"><!-- --></A><H3>
getAttribute</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A> <B>getAttribute</B>(<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;name)</PRE>
<DL>
<DD>Returns the servlet container attribute with the given name, 
 or <code>null</code> if there is no attribute by that name.
 An attribute allows a servlet container to give the
 servlet additional information not
 already provided by this interface. See your
 server documentation for information about its attributes.
 A list of supported attributes can be retrieved using
 <code>getAttributeNames</code>.

 <p>The attribute is returned as a <code>java.lang.Object</code>
 or some subclass.
 Attribute names should follow the same convention as package
 names. The Java Servlet API specification reserves names
 matching <code>java.*</code>, <code>javax.*</code>,
 and <code>sun.*</code>.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - a <code>String</code> specifying the name 
                        of the attribute
<DT><B>Returns:</B><DD>an <code>Object</code> containing the value 
                        of the attribute, or <code>null</code>
                        if no attribute exists matching the given
                        name<DT><B>See Also:</B><DD><A HREF="../../javax/servlet/ServletContext.html#getAttributeNames()"><CODE>getAttributeNames()</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="getAttributeNames()"><!-- --></A><H3>
getAttributeNames</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/util/Enumeration.html" title="class or interface in java.util">Enumeration</A> <B>getAttributeNames</B>()</PRE>
<DL>
<DD>Returns an <code>Enumeration</code> containing the 
 attribute names available
 within this servlet context. Use the
 <A HREF="../../javax/servlet/ServletContext.html#getAttribute(java.lang.String)"><CODE>getAttribute(java.lang.String)</CODE></A> method with an attribute name
 to get the value of an attribute.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>an <code>Enumeration</code> of attribute 
                        names<DT><B>See Also:</B><DD><A HREF="../../javax/servlet/ServletContext.html#getAttribute(java.lang.String)"><CODE>getAttribute(java.lang.String)</CODE></A></DL>
</DD>
</DL>
<HR>

<A NAME="setAttribute(java.lang.String, java.lang.Object)"><!-- --></A><H3>
setAttribute</H3>
<PRE>
void <B>setAttribute</B>(<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;name,
                  <A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/Object.html" title="class or interface in java.lang">Object</A>&nbsp;object)</PRE>
<DL>
<DD>Binds an object to a given attribute name in this servlet context. If
 the name specified is already used for an attribute, this
 method will replace the attribute with the new to the new attribute.
 <p>If listeners are configured on the <code>ServletContext</code> the  
 container notifies them accordingly.
 <p>
 If a null value is passed, the effect is the same as calling 
 <code>removeAttribute()</code>.
 
 <p>Attribute names should follow the same convention as package
 names. The Java Servlet API specification reserves names
 matching <code>java.*</code>, <code>javax.*</code>, and
 <code>sun.*</code>.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - a <code>String</code> specifying the name 
                        of the attribute<DD><CODE>object</CODE> - an <code>Object</code> representing the
                        attribute to be bound</DL>
</DD>
</DL>
<HR>

<A NAME="removeAttribute(java.lang.String)"><!-- --></A><H3>
removeAttribute</H3>
<PRE>
void <B>removeAttribute</B>(<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;name)</PRE>
<DL>
<DD>Removes the attribute with the given name from 
 the servlet context. After removal, subsequent calls to
 <A HREF="../../javax/servlet/ServletContext.html#getAttribute(java.lang.String)"><CODE>getAttribute(java.lang.String)</CODE></A> to retrieve the attribute's value
 will return <code>null</code>.

 <p>If listeners are configured on the <code>ServletContext</code> the 
 container notifies them accordingly.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>name</CODE> - a <code>String</code> specifying the name 
                        of the attribute to be removed</DL>
</DD>
</DL>
<HR>

<A NAME="getServletContextName()"><!-- --></A><H3>
getServletContextName</H3>
<PRE>
<A HREF="http://java.sun.com/j2se/1.5/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A> <B>getServletContextName</B>()</PRE>
<DL>
<DD>Returns the name of this web application corresponding to this ServletContext as specified in the deployment
 descriptor for this web application by the display-name element.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>The name of the web application or null if no name has been declared in the deployment descriptor.<DT><B>Since:</B></DT>
  <DD>Servlet 2.3</DD>
</DL>
</DD>
</DL>
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