ide/usersguide/javahelp/org/netbeans/modules/usersguide/f1_web_apps010.htm - netbeans - Git at Google

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 <title>web.xml Visual Editor: Environment Entries</title>
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 <h1>web.xml Visual Editor: Environment Entries</h1>
 <a name="BEGIN" id="BEGIN"></a>
 <p>Use the Environment Entries section to add, remove, and view the web application's environment variables. Application environment entries are initialization variables that are available throughout a web application. You can use them, for example, to validate the object's type.
 <object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
 <param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1114">
 <param name="text" value="<html><u>How?</u></html>">
 <param name="textFontSize" value="medium">
 <param name="textColor" value="blue">
 </object>
 </p>
 <p>You access application environment variables in the <code dir="ltr">java:comp/env</code> context through a JNDI lookup, unlike context parameters, which you access via a <code dir="ltr">ServletContext</code> object. So, you would extract the value of an application environment variable as shown in <a href="#CHDFAHIH">Example: Extracting the value of an application environment variable</a>.</p>
 <div id="NBCSH3847"><a id="CHDFAHIH" name="CHDFAHIH"></a>
 <p>Example: Extracting the value of an application environment variable</p>
 <pre xml:space="preserve" dir="ltr">
 InitialContext context = new InitialContext();
 String header = (String) context.lookup("java:comp/env/headerPage");
 </pre>
 <!-- -->
 <p>The JNDI lookup method expects the type specified by the <code dir="ltr">env-entry-type</code> element and throws an exception if the returned value is not of that type.</p>
 <p>To declare an application environment variable, you must register it in the web.xml file. When you do this, you provide information needed by the server to use the parameter. You tell the server which value should be returned when an environment entry is referred to in the web application.</p>
 <p>In the Visual Editor, click <b>References</b> at the top of the editor to open the References section, then click the Environment Entries header to open the Environment Entries section.
 <object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
 <param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1114">
 <param name="text" value="<html><u>How?</u></html>">
 <param name="textFontSize" value="medium">
 <param name="textColor" value="blue">
 </object>
 </p>
 <p>Click <b>Add</b> to define an environment entry element with the following properties:</p>

 <table summary="User interface elements and descriptions" dir="ltr" border="1" width="100%" frame="hsides" rules="groups" cellpadding="3" cellspacing="0">
 <col width="24%" />
 <col width="*" />
 <thead>
 <tr align="left" valign="top">
 <th align="left" valign="bottom" id="r1c1-t17">Element</th>
 <th align="left" valign="bottom" id="r1c2-t17">Description</th>
 </tr>
 </thead>
 <tbody>
 <tr align="left" valign="top">
 <td align="left" id="r2c1-t17" headers="r1c1-t17">
 <p>Entry Name</p>
 </td>
 <td align="left" headers="r2c1-t17 r1c2-t17">Specifies the variable's name, such as <code dir="ltr">headerPage</code>.</td>
 </tr>
 <tr align="left" valign="top">
 <td align="left" id="r3c1-t17" headers="r1c1-t17">
 <p>Entry Type</p>
 </td>
 <td align="left" headers="r3c1-t17 r1c2-t17">Specifies the variable's name for validation, such as <code dir="ltr">java.lang.String</code>.</td>
 </tr>
 <tr align="left" valign="top">
 <td align="left" id="r4c1-t17" headers="r1c1-t17">
 <p>Entry Value</p>
 </td>
 <td align="left" headers="r4c1-t17 r1c2-t17">Specifies the parameter's value, such as <code dir="ltr">mypages/header-0034.html</code>.</td>
 </tr>
 <tr align="left" valign="top">
 <td align="left" id="r5c1-t17" headers="r1c1-t17">
 <p>Description</p>
 </td>
 <td align="left" headers="r5c1-t17 r1c2-t17">Specifies a description, such as H<code dir="ltr">eader Page for Travel Agency Application</code>.</td>
 </tr>
 </tbody>
 </table>
 <br />
 <!-- -->
 <a id="NBCSH3852" name="NBCSH3852"></a>
 <hr><p><b>Related Topics</b></p>
 <p><i>Developing Applications with NetBeans IDE</i>,
 <object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
 <param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG2812">
 <param name="text" value="<html><u>&quot;About Deployment Descriptors&quot;</u></html>">
 <param name="textFontSize" value="medium">
 <param name="textColor" value="blue">
 </object>
 </p>
 <p><i>Developing Applications with NetBeans IDE</i>,
 <object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
 <param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1111">
 <param name="text" value="<html><u>&quot;Configuring a Web Application&quot;</u></html>">
 <param name="textFontSize" value="medium">
 <param name="textColor" value="blue">
 </object>
 </p>

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 <td align="left" width="86%"><a href="legal_notice.htm">
 Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements; and to You under the Apache License, Version 2.0.</a>
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	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
	<!--

	Licensed to the Apache Software Foundation (ASF) under one
	or more contributor license agreements. See the NOTICE file
	distributed with this work for additional information
	regarding copyright ownership. The ASF licenses this file
	to you under the Apache License, Version 2.0 (the
	"License"); you may not use this file except in compliance
	with the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing,
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	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en" dir="ltr">
	<head>
	<title>web.xml Visual Editor: Environment Entries</title>
	<link rel="stylesheet" href="ide.css" title="Oracle BLAFDoc" type="text/css"/>
	</head>

	<body>
	<p><a id="dd_multiview_references_envEntriesNode" name="dd_multiview_references_envEntriesNode"></a></p>
	<div id="NBCSH3846"><!-- infolevel="all" infotype="General" --><a id="sthref520" name="sthref520"></a>
	<h1>web.xml Visual Editor: Environment Entries</h1>
	<a name="BEGIN" id="BEGIN"></a>
	<p>Use the Environment Entries section to add, remove, and view the web application's environment variables. Application environment entries are initialization variables that are available throughout a web application. You can use them, for example, to validate the object's type.
	<object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
	<param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1114">
	<param name="text" value="<html><u>How?</u></html>">
	<param name="textFontSize" value="medium">
	<param name="textColor" value="blue">
	</object>
	</p>
	<p>You access application environment variables in the <code dir="ltr">java:comp/env</code> context through a JNDI lookup, unlike context parameters, which you access via a <code dir="ltr">ServletContext</code> object. So, you would extract the value of an application environment variable as shown in <a href="#CHDFAHIH">Example: Extracting the value of an application environment variable</a>.</p>
	<div id="NBCSH3847"><a id="CHDFAHIH" name="CHDFAHIH"></a>
	<p>Example: Extracting the value of an application environment variable</p>
	<pre xml:space="preserve" dir="ltr">
	InitialContext context = new InitialContext();
	String header = (String) context.lookup("java:comp/env/headerPage");
	</pre>
	<!-- -->
	<p>The JNDI lookup method expects the type specified by the <code dir="ltr">env-entry-type</code> element and throws an exception if the returned value is not of that type.</p>
	<p>To declare an application environment variable, you must register it in the web.xml file. When you do this, you provide information needed by the server to use the parameter. You tell the server which value should be returned when an environment entry is referred to in the web application.</p>
	<p>In the Visual Editor, click <b>References</b> at the top of the editor to open the References section, then click the Environment Entries header to open the Environment Entries section.
	<object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
	<param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1114">
	<param name="text" value="<html><u>How?</u></html>">
	<param name="textFontSize" value="medium">
	<param name="textColor" value="blue">
	</object>
	</p>
	<p>Click <b>Add</b> to define an environment entry element with the following properties:</p>

	<table summary="User interface elements and descriptions" dir="ltr" border="1" width="100%" frame="hsides" rules="groups" cellpadding="3" cellspacing="0">
	<col width="24%" />
	<col width="*" />
	<thead>
	<tr align="left" valign="top">
	<th align="left" valign="bottom" id="r1c1-t17">Element</th>
	<th align="left" valign="bottom" id="r1c2-t17">Description</th>
	</tr>
	</thead>
	<tbody>
	<tr align="left" valign="top">
	<td align="left" id="r2c1-t17" headers="r1c1-t17">
	<p>Entry Name</p>
	</td>
	<td align="left" headers="r2c1-t17 r1c2-t17">Specifies the variable's name, such as <code dir="ltr">headerPage</code>.</td>
	</tr>
	<tr align="left" valign="top">
	<td align="left" id="r3c1-t17" headers="r1c1-t17">
	<p>Entry Type</p>
	</td>
	<td align="left" headers="r3c1-t17 r1c2-t17">Specifies the variable's name for validation, such as <code dir="ltr">java.lang.String</code>.</td>
	</tr>
	<tr align="left" valign="top">
	<td align="left" id="r4c1-t17" headers="r1c1-t17">
	<p>Entry Value</p>
	</td>
	<td align="left" headers="r4c1-t17 r1c2-t17">Specifies the parameter's value, such as <code dir="ltr">mypages/header-0034.html</code>.</td>
	</tr>
	<tr align="left" valign="top">
	<td align="left" id="r5c1-t17" headers="r1c1-t17">
	<p>Description</p>
	</td>
	<td align="left" headers="r5c1-t17 r1c2-t17">Specifies a description, such as H<code dir="ltr">eader Page for Travel Agency Application</code>.</td>
	</tr>
	</tbody>
	</table>
	<br />
	<!-- -->
	<a id="NBCSH3852" name="NBCSH3852"></a>
	<hr><p><b>Related Topics</b></p>
	<p><i>Developing Applications with NetBeans IDE</i>,
	<object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
	<param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG2812">
	<param name="text" value="<html><u>"About Deployment Descriptors"</u></html>">
	<param name="textFontSize" value="medium">
	<param name="textColor" value="blue">
	</object>
	</p>
	<p><i>Developing Applications with NetBeans IDE</i>,
	<object classid="java:org.netbeans.modules.javahelp.BrowserDisplayer">
	<param name="content" value="http://www.oracle.com/pls/topic/lookup?ctx=nb8200&id=NBDAG1111">
	<param name="text" value="<html><u>"Configuring a Web Application"</u></html>">
	<param name="textFontSize" value="medium">
	<param name="textColor" value="blue">
	</object>
	</p>

	<!-- -->
	<!-- Start Footer -->


	<table summary="" cellspacing="0" cellpadding="0" width="100%">
	<tr>
	<td align="left" width="86%"><a href="legal_notice.htm">
	Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements; and to You under the Apache License, Version 2.0.</a>
	</td>
	</tr>
	</table>
	<!-- -->
	</body>
	</html>