/ W3SCHOOLS

W3schools - JSP_Elements

이 페이지는 다음에 대한 공부 기록입니다
Lecture에서 배웠던 내용을 복습하며 작성했습니다

찾으시는 정보가 있으시다면
주제별reference를 이용하시거나
우측 상단에 있는 검색기능을 이용해주세요

Elements

Scriptlet

Can contain any number of JAVA lang statements, variable or method declarations, or expressing that are valid in the page scripting lang

<!-- Syntax -->
<% code fragment %>
<!-- Can write the XML equivalent -->
<jsp:scriptlet>
code fragment
</jsp:scriptlet>
<!--- Any text, HTML or JSP elements you write must be outside the scriptlet -->
<body>
	Hello World!<br>
	<%
		out.println(“Id address = ” + request.getRemoteAddr());
    %>
</body>

Declaration

It declares one or more variables or methods that you can use in Java code later in the JSP file

  • Must declare the variable or method before use it
<!-- Syntax -->
<%! Declaration; [ declaration; ] + … %>
<% Can write the XML equivalent %>
<jsp:declaration>
	Code fragment
</jsp:declaration>
<!--  in jsp -->
<%! int i = 0;%>
<%! int a, b, c; %>
<%! Circle a = new Circle(2.0); %>

Expression

JSP expression element contains a scripting lang expression that is evaluated, converted to a String, and inserted where the expression appears in the JSP file

The expression element can contain any expression that is valid according to the Java lang Specification but you can’t use a semicolon to end an expression

<!-- Syntax -->
<%= expression %>
<!-- Can write the XML equivalent -->
<jsp:expression>
	expression
</jsp:expression>
<!-- in jsp -->
<p> date : <%= (new java.util.Date()).toLocalString() %></p>

Comment

<%-- This is JSP comment --%>

Directive

Directive affects the overall structure of the servlet class

<%@ directive attribute= “value” %>
<%@ page …. %>
<!-- Defines page-dependent attributes(scripting lang, error page, buffering requirements…) -->
<%@ include …. %>
<!-- includes a file during the translation phase -->
<%@ taglib …. %>
<!--- Declares a tag library, containing custom actions, used in the page -->

Action

It uses constructs in XML syntax to control the behavior of the servlet engine

<jsp:action_name attribute=“value”>

Action elements are basically predefined functions

Syntax Purpose
jsp:include Include a file at the time the page is requested
jsp:useBean Finds or instantiates a JavaBean
jsp:setProperty Sets the property of a JavaBean
jsp:getProperty Inserts the property of a JavaBean into the output
jsp:forward Forwards the requester to a new page
jsp:plugin Generates browser-specific code
that makes an OBJECT or EMBED tag for the Java plugin
jsp:element Defines XML elements dynamically
jsp:attribute Defines dynamically-defined XML element’s attribute
jsp:body Defines dynamically-defined XML element’s body
jsp:text Used to write template text in JSP pages and documents

Implicit Object

JSP supports nine automatically defined variables, which are also called implicit

Object Description
request Is the HttpServletRequest object associated with the request
response Is the HttpServletResponse object associated with the response to the client
out Is the PrintWriter object used to send output to the client
session Is the HttpSession object associated with the request
application Is the ServletContext object associated with the application context
config Is the ServletConfig object associated with the page
pageContext Encapsulates use of server-specific features like higher performance JspWriters
page This is simply a synonym for this,
and is used to call the methods defined by the translated servlet class
Exception It is allows the exception data to be accessed by designated JSP

Control-Flow

Can use all the APIs and building blocks of Java in JSP programming including decision-making statements, loops