java类库详细讲解

				
				
				
				Implementing Conditional Content on a JSP Page
				(Java Developers Almanac Example)
				
				
				
				
				
				
								    BODY CODE  {font-family: Courier, Monospace;				           font-size: 11pt}				    TABLE, BODY				          {font-family: Verdana, Arial, Helvetica, sans-serif;				           font-size: 10pt}				    PRE   {font-family: Courier, Monospace;				           font-size: 10pt}				    H3    {font-family: Verdana, Arial, Helvetica, sans-serif;				           font-size: 11pt}				    A.eglink {text-decoration: none}				    A:hover.eglink {text-decoration: underline}				    -->
				
				
				
				
				
				The Java Developers Almanac 1.4
				
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				    javax.servlet.jsp
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				        Java Server Pages Output
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				    e1058.  
				    Implementing Conditional Content on a JSP Page
				
				Any non-JSP code in a JSP file is called template text and is
				automatically written to the output stream.  By wrapping template text
				fragments in scriptlets, it is possible to dynamically choose which
				fragment to generate.
				
				 These examples generate different template text depending on
				the value of request parameters:
				
				
				
				
				    <% if ("someValue".equals(request.getParameter("param1"))) { %>
				        Generate this template text if param1 equals someValue
				    <% } else { %>
				        Otherwise generate this template text
				    <% } %>
				    
				    
				    <% switch (Integer.parseInt(request.getParameter("param2"))) {
				        case 0: %>
				           Generate this template text if param2 equals 0
				    <%     break;
				        case 1: %>
				           Generate this template text if param2 equals 1
				    <%     break;
				        default: %>
				           Generate this template text if param2 equals anything else
				    <% } %>
				
				See also e1068 Conditionally Generating Output Using JSTL in a JSP Page.
				
				
				
				
				             Related Examples
				        
				
				
				
				
				e1056. 
				    Commenting a JSP Page
				
				
				
				e1057. 
				    Generating Dynamic Content on a JSP Page
				
				
				
				e1059. 
				    Handling Unhandled Exceptions in a JSP Page
				
				
				
				
				
				
				
				
				        See also: 
				
				    Java Server Pages
				  
				
				
				    Java Server Pages Headers
				  
				
				
				    Java Server Pages Input
				  
				
				
				
				
				
				
				
				
				
				© 2002 Addison-Wesley.