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- <html>
- <head>
- <title>JSP 2.0 Expression Language - Implicit Objects</title>
- </head>
- <body>
- <h1>JSP 2.0 Expression Language - Implicit Objects</h1>
- <hr>
- This example illustrates some of the implicit objects available
- in the Expression Lanaguage. The following implicit objects are
- available (not all illustrated here):
- <ul>
- <li>pageContext - the PageContext object</li>
- <li>pageScope - a Map that maps page-scoped attribute names to
- their values</li>
- <li>requestScope - a Map that maps request-scoped attribute names
- to their values</li>
- <li>sessionScope - a Map that maps session-scoped attribute names
- to their values</li>
- <li>applicationScope - a Map that maps application-scoped attribute
- names to their values</li>
- <li>param - a Map that maps parameter names to a single String
- parameter value</li>
- <li>paramValues - a Map that maps parameter names to a String[] of
- all values for that parameter</li>
- <li>header - a Map that maps header names to a single String
- header value</li>
- <li>headerValues - a Map that maps header names to a String[] of
- all values for that header</li>
- <li>initParam - a Map that maps context initialization parameter
- names to their String parameter value</li>
- <li>cookie - a Map that maps cookie names to a single Cookie object.</li>
- </ul>
-
- <blockquote>
- <u><b>Change Parameter</b></u>
- <form action="implicit-objects.jsp" method="GET">
- foo = <input type="text" name="foo" value="${param["foo"]}">
- <input type="submit">
- </form>
- <br>
- <code>
- <table border="1">
- <thead>
- <td><b>EL Expression</b></td>
- <td><b>Result</b></td>
- </thead>
- <tr>
- <td>\${param.foo}</td>
- <td>${param.foo} </td>
- </tr>
- <tr>
- <td>\${param["foo"]}</td>
- <td>${param["foo"]} </td>
- </tr>
- <tr>
- <td>\${header["host"]}</td>
- <td>${header["host"]}</td>
- </tr>
- <tr>
- <td>\${header["accept"]}</td>
- <td>${header["accept"]}</td>
- </tr>
- <tr>
- <td>\${header["user-agent"]}</td>
- <td>${header["user-agent"]}</td>
- </tr>
- </table>
- </code>
- </blockquote>
- </body>
- </html>
-