e1059. implementing conditional content on a jsp page.txt

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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 e1069 Conditionally Generating Output Using JSTL in a JSP Page.