Tài liệu Session 2: Using JSP Tags docx

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Tiêu đề	Using JSP Tags
Trường học	eACCP
Chuyên ngành	Dynamic Pages Using JSP
Thể loại	tài liệu
Năm xuất bản	2003
Thành phố	Hanoi

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Số trang	41
Dung lượng	293 KB

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Session 2 Using JSP Tags eACCP2003/Dynamic Pages Using JSP/ Session 2/ 2 of 45 Session Objectives  Describe the various elements of a JavaServer Page  Describe the various JSP Tags in brief eACCP2003/Dynamic Pages Using JSP/ Session 2/ 3 of 45 What does a JSP look like?  Three main JSP constructs:  Directives  Allows one to control structure of the servlet  Scripting Elements  Used to include Java code  Actions  Specific tags that affect the runtime behavior of the JSPs eACCP2003/Dynamic Pages Using JSP/ Session 2/ 4 of 45 An Example <HTML> <HEAD><TITLE>MyFirstProgram.jsp</TITLE></HEAD> <BODY> <! MyFirstProgram.JSP > <%@ page import = "java.util.Date" %> <% out.println("Hello there!"); %> <Br> <%= "Current date is " + new Date() %> </BODY> </HTML> Fixed Template data JSP Directive JSP Expression JSP Scriptlet eACCP2003/Dynamic Pages Using JSP/ Session 2/ 5 of 45 What happens under the hood? User Request Web Server/ Servlet Engine JSP Handler Servlet (Page Compilation Servlet) New or modified file? Compile into Servlet Execute Servlet Yes No eACCP2003/Dynamic Pages Using JSP/ Session 2/ 6 of 45 Various Elements in a JSP  Directives  page  Defines information that will be globally available for a JSP  include  Used to insert text and code at JSP translation time  taglib  Defines a mechanism for extending the current set of JSP tags eACCP2003/Dynamic Pages Using JSP/ Session 2/ 7 of 45 Different Attributes of the Page Directive Attribute Definition language = ”<scriptingLanguage>” This attribute tells the server about the language to be used to complete the JSP file. At present, Java is the only language that can be used. extends = ”<className>" This attribute defines the parent class that the generated servlet will extend. import = ”<importList>" This attribute defines the list of packages that will be available to this JSP. However, a comma must separate each package. session = "true | false" This attribute determines whether the session data will be available to this page. The default is true. buffer = "none | <size in kb>" This attribute determines whether the output stream is buffered. The default value is 8 kb. eACCP2003/Dynamic Pages Using JSP/ Session 2/ 8 of 45 Different Attributes of the Page Directive – (1) Attribute Definition autoFlush = "true | false" Determines whether the output buffer will be flushed automatically, or whether it will raise an exception when the buffer is full. The default is true. isThreadSafe = "true | false" Specifies whether page can service more than one request at a time. The default is true. info = ”<text>" Specifies information about the JSP, can be accessed by Servlet.getServletInfo(). errorPage = ”<error_URL>" This attribute represents the relative URL to the JSP that will handle exceptions. isErrorPage = "true | false" This attribute states whether or not the JSP is an errorPage. The default is false. contentType = ”<ctinfo>" This attribute represents the MIME type and character set of the response. eACCP2003/Dynamic Pages Using JSP/ Session 2/ 9 of 45 Using page Attributes - An example <%@ page language = "java" import = "java.rmi.*, java.util.*" session = "true" buffer = "12kb" autoFlush = "true" info = "page directive jsp" errorPage = "Error.jsp" isErrorPage = "false" isThreadSafe = "false" %> <HTML> <TITLE> JSP Elements </TITLE> <HEAD> <H1> JSP Elements </H1> </HEAD> <BODY> </BODY> </HTML> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 10 of 45 More on Directives  include directive  Syntax <%@ include file = “relativeURLspec” %>  taglib directive  Syntax <%@ taglib uri = “tagLibraryURI” prefix = “tagPrefix” %> [...]... < /jsp: include> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 24 of 45 Employeeinfo .jsp eACCP2003/Dynamic Pages Using JSP/ Session 2/ 21 of 45 JSP. .. usually JavaBeans        eACCP2003/Dynamic Pages Using JSP/ Session 2/ 19 of 45 JSP Standard Actions – (1)      Associates an instance of a pre-defined JavaBean with a given scope and ID Sets the value of a bean’s property    Accesses...   Enables the JSP engine to dispatch the current request to a static resource, a servlet, or to another JSP at runtime The syntax is as follows: < /jsp: forward> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 26 of 45 Using - An Example s Forward .jsp Using the JSP Forward action... eACCP2003/Dynamic Pages Using JSP/ Session 2/ 31 of 45 } Using - An Example (1) UsePlugin .jsp < /jsp: plugin> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 32 of 45 JSP Standard Actions – (6)  JSP actions have the following characteristics:         These tags are case-sensitive... request.getParameter("employee")); out.println("Title:" + request.getParameter("title")); %> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 28 of 45 Forward .jsp eACCP2003/Dynamic Pages Using JSP/ Session 2/ 22 of 45 Using - An Example This JSP will search for an employee’s... ((request.getParameter("companyID")).equals("1")) {%> < /jsp: forward> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 27 of 45 Using - An Example – (1) MarthaHome .jsp < /jsp: plugin> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 30 of 45 Using - An Example HelloApplet.java public class HelloApplet extends JApplet { public HelloApplet()... Pages Using JSP/ Session 2/ 16 of 45 JSP Scripting Elements – (5) Declarations are the definition of class-level variables and methods that are used in a JSP Syntax: Example: Declaration This page has been accessed time(s) since the server was rebooted eACCP2003/Dynamic Pages Using JSP/ Session 2/ 17 of 45 JSP Scripting . Session 2 Using JSP Tags eACCP2003/Dynamic Pages Using JSP/ Session 2/ 2 of 45 Session Objectives  Describe the various. Page  Describe the various JSP Tags in brief eACCP2003/Dynamic Pages Using JSP/ Session 2/ 3 of 45 What does a JSP look like?  Three main JSP constructs:  Directives  Allows

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