JSP

Key Acronyms          JSP  = JavaServer Pages JSTL = JSP Standard Tag Library TLD  = Tag Library Descriptor WAR  = Web-application ARchive EL = Expression Language	Page Lifecycle 1. Page Translation 2. Page Compilation 3. Load Class 4. Create Object 5. Call jspInit() 6. Call _jspService() 7. Call jspDestroy()
BASIC SYNTAX Directive Elements (translation phase) <%@ page ... %>                                      - <jsp:directive.page .. /> in XML <%@ include file="filename" %>                       - <jsp:directive.include .. /> in XML <%@ taglib prefix="shortName" uri="tldUniqueName" %> - xmlns:prefix="tldUniqueName" in XML Scripting Elements <%  ...; %> - script-let   - in XML <%= ...  %> - expression   - in XML <%! ...; %> - declaration  - in XML <%-- ... --%> - comment    - in XML ${ }       - JSTL 1.0/JSP2.0
Implicit objects (note not available in declarations) application  - ServletContext config       - ServletConfig exception    - Throwable (only for pages with page directive isErrorPage="true") request      - HttpServletRequest response     - HttpServletResponse out          - JSPWriter page         - Object pageContext  - PageContext session      - HttpSession (only for pages with page directive session="true")
Page Directive Attributes autoFlush    - Boolean indicating whether buffer should flush when full (true) buffer       - buffer size in kilobytes, e.g. "32kb" contentType  - MIME type and character encoding of output (text/html;ISO-8859-1) errorPage    - URL of a JSP page capable of handling errors for this page (null) extends      - sub-class of javax.servlet.jsp.JspPage to use import       - comma-separated list of packages/classes (java.lang.*, etc..) isErrorPage  - boolean indicating page can accept errors (false) isThreadSafe - Boolean indicating whether page is thread-safe (true) language     - scripting language (java) pageEncoding - character encoding of output (ISO-8859-1) session      - boolean indicating whether takes part in a session (true)
Action Elements/Tags (request processing phase) <jsp:useBean id="beanName" class="com.classes.BeanClass" [scope="page"]/> <jsp:useBean id="beanName" class="com.classes.BeanClass" type="com.classes.BeanSuperClass"/> <jsp:useBean id="beanName" beanName="serializedName" type="com.classes.BeanSuperClass"/> <jsp:getProperty name="beanName" property="propertyName"/> <jsp:setProperty name=“beanName" property="propertyName" value="propertyValue"/> <jsp:setProperty name=“beanName" property="propertyName" [param="requestParamName"]/> <jsp:include page="relativeURL"/> <jsp:forward page="relativeURL"/> <jsp:param name="paramName" value="paramValue"/> <jsp:plugin/>
JSTL libraries http://java.sun.com/jsp/jstl/core (c) http://java.sun.com/jsp/jstl/xml (x) http://java.sun.com/jsp/jstl/fmt (fmt) http://java.sun.com/jsp/jstl/sql (sql) http://java.sun.com/jsp/jstl/fn (fn) JSTL functions (JSTL 1.1) c:out(value) c:param(name, value) c:forEach(var, items, varStatus) c:forToken c:url c:import(url)   fmt:formatNumber(value, pattern) fmt:parseNumber fmt:formatDate fmt:parseDate fmt:timeZone fmt:setTimeZone fmt:setLocale(value) fmt:bundle(basename)   fn:contains(string, substring) fn:containsIgnoreCase(string, substring) fn:endsWith(string, suffix) fn:escaleXml(string) fn:indexOf(string, substring) fn:join(array, separator) fn:length(item) fn:replace(string, before, after) fn:split(string, separator) fn:startsWith(string, prefix) fn:substring(string, begin, end) fn:substringAfter(string, substring) fn:substringBefore(string, substring) fn:toLowerCase(string) fn:toUpperCase(string) fn:trim(string)   sql:setDataSource(var,driver,url) sql:query(var,datasource) sql:update sql:transaction(dataSource)   x:parse(source, var) x:out(select) x:transform(source, xslt)
PageContext methods setAttribute(name, valueObject) getAttribute(name) setAttribute(name, valueObject, scope) getAttribute(name, scope) getAttributeNamesInScope(scope) removeAttribute(name, scope) getServletContext() getSession() getResponse() getRequest()	Variable scopes jsp:usebean  Servlet ===========  ======= page         PageContext.PAGE_SCOPE request      PageContext.REQUEST_SCOPE session      PageContext.SESSION_SCOPE application  PageContext.APPLICATION_SCOPE
Custom tag interfaces Tag          - base class for simple tags IterationTag - adds doAfterBody() for iteration processing     (default implementation -> TagSupport) BodyTag      - adds doInitBody() for handling tags with bodies (default implementation -> BodyTagSupport) Tag methods (in order of execution) setPageContext() - called by the container setParent()      - called by the container setXXXXXX()      - called for each attribute doStartTag()     - returns either EVAL_BODY_INCLUDE or SKIP_BODY (or EVAL_BODY_BUFFERED for BodyTag) setBodyContent() - called by the container (BodyTag only if EVAL_BODY_BUFFERED) doInitBody()     - return void             (BodyTag only if EVAL_BODY_BUFFERED) doAfterBody()    - returns either EVAL_BODY_AGAIN or SKIP_BODY (IterationTag and BodyTag) doEndTag()       - returns either EVAL_PAGE or SKIP_PAGE release()        - called when tag handler no longer required   doStart doAfterBody doEndTag EVAL_BODY_INCLUDE All     EVAL_BODY_BUFFERED BodyTag     EVAL_BODY_AGAIN   Iteration   SKIP_BODY All Iteration   EVAL_PAGE     All SKIP_PAGE     All
Expression Language - Literals true, false, 5, -5, 5.5, 5.5E5, "string", 'string', null Expression Language - Operators +,-,*,/,%,==,!,!=,<,>,<=,>=,&&,||,(,) condition ? ifTrue : ifFalse empty set Expression Language - Equivalent JSP expressions {$list[1]}               == <%= list.elementAt(1) %> {$map.name}              == <%= map.get("name") %> {$map['name']}           == <%= map.get("name") %> {$map[name]}             == <%= map.get(pageContext.findAttribute("name")) %> {$bean.property}         == <%= bean.getProperty() %>   {$pageContext.response}  == <%= pageContext.getResponse() %> {$pageContext.session}   == <%= pageContext.getSession() %> {$pageContext.context}   == <%= pageContext.getServletContext() %> {$pageContext.request.requestURI} == <%= pageContext.getRequest().getRequestURI() %>   {$param.name}            == <%= request.getParameter("name") %> {$paramValues.name}      == <%= request.getParameterValues("name") %> {$header.name}           == <%= request.getHeader("name") %> {$headerValues.name}     == <%= request.getHeaderValues("name") %>   {$pageScope.cart.count}  == <%= pageContext.getAttribute("cart", PageContext.PAGE_SCOPE).getCount() %> {$requestScope.cart}     == <%= pageContext.getAttribute("cart", PageContext.REQUEST_SCOPE) %> {$sessionScope.cart}     == <%= pageContext.getAttribute("cart", PageContext.SESSION_SCOPE) %> {$applicationScope.cart} == <%= pageContext.getAttribute("cart", PageContext.APPLICATION_SCOPE) %>   {$mytl:myfn()}           - calls the myfn() function of the mytl tag library   EL functions are code as public static methods and identified using the function element of the TLD.
Tag Library Descriptor (META-INF/taglib.tld) taglib short-name [display-name] [description] [uri] - if implicit taglib URI indirection is used tlib-version jsp-version tag* name [display-name] [description] tag-class   - implementation of Tag [tei-class] - implementation of TagExtraInfo [body-content] - { empty | JSP | tagdependent } [variable]* [attribute]* name [description] [required]    - { yes | no | true | false } [rtexprvalue] - { yes | no | true | false } request time expressions [type]        - request time expression type (default java.lang.String) [example] [function]* name [display-name] [description] function-class function-signature [listener]
WAR structure /WEB-INF/web.xml /WEB-INF/classes/ /WEB-INF/lib/