Java Server Pages

JavaServer Pages (JSP) Svetlin Nakov Borislava Spasova Creating Dynamic Web Pages

Contents ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Contents (2) ,[object Object],[object Object],[object Object],[object Object]

Introduction to JSP Technology

What is JSP? ,[object Object],[object Object],[object Object],[object Object],[object Object]

JSP Technology ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Date JSP Page – Example ,[object Object],<html> <head><title>Date JSP example </title></head> <body> The date is: <% out.println(new java.util.Date()); %> </body> </html> date.jsp

JSP Expressions ,[object Object],[object Object],[object Object],<%= Java e xpression %> The time is : <%= new java.util.Date() %> The square root of 2 is : <%= Math.sqrt(2) %> The value of PI is: <%= Math.PI %>

Predefined JSP Variables ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

JSP Expressions – More Examples ,[object Object],[object Object],[object Object],Your hostname: <%= request.getRemoteHost() %> Session timeout : <%= session.getMaxInactiveInterval() %> Browser: <%= request.getHeader("User-Agent") %>

JSP Scriptlets ,[object Object],[object Object],<% Java c ode %> <% String queryData = request.getQueryString(); out.println("Attached GET data: " + queryData); %>

JSP Scriptlets – Example ,[object Object],[object Object],<% if (Math.random() < 0.5) { %> Have a <B>nice</B> day! <% } else { %> Have an <B>interesting</B> day! <% } %> <% for (int i=0; i<10; i++) { %> <%= i %> * <%= i %> = <%= i*i %> <br> <% } %>

JSP Internals How JSP Pages Are Transformed to Servlets?

JSP Technology Internals ,[object Object],[object Object],[object Object],[object Object],JSP Page ( date .jsp ) Java servlet ( date .java ) Compiled Java servlet ( date . class ) JSP compiler javac

JSP Technology Internals ,[object Object],<html> <head><title>Date JSP example</title></head> <body> The date is: <% out.println(new java.util.Date()); %> </body> </html> date.jsp JSP compilation package org.apache.jsp; public final class date_jsp extends HttpJspBase implements JspSourceDependent { ... } date_jsp.java ebappsSP-Demosdate.jsp orkatalinaocalhostJSP-Demosrgpachesp

JSP Declarations and Directives

JSP Declarations ,[object Object],[object Object],[object Object],<%! Java c ode (fields and methods) %> <%! long counter = 0; public void getCounter() { return counter; } %>

JSP Declarations ,[object Object],[object Object],[object Object],[object Object],<%! private static int accessCount = 0; %> This page has been accessed <%= ++accessCount %> times.

JSP Directives ,[object Object],[object Object],[object Object],<%@ directive attribute="value" %> <%@ directive attribute1="value1" attribute2="value2" ... attributeN="valueN" %>

The JSP @ page Directive ,[object Object],[object Object],[object Object],[object Object],import="package.class " or import="package.class1, ..., package.classN" <%@ page import="java.util.*" %>

The JSP @ page Directive (2) ,[object Object],[object Object],[object Object],contentType="MIME-Type" or contentType="MIME-Type; charset=Character-Set" <%@ page contentType="text/plain" %> <% response.setContentType("text/plain"); %>

The JSP @ page Directive (3) ,[object Object],[object Object],[object Object],session="true|false" errorPage="url" isErrorPage="true|false"

The JSP @ include Directive ,[object Object],[object Object],[object Object],[object Object],<%@ include file="relative url" %> <%@ include file="/ include/ menu.jsp" %>

Using JSP @ include Directive ,[object Object],< html > < body > <%@ include file="/navbar.html" %>  </ body > </ html >

Dynamic Include ,[object Object],[object Object],[object Object],<jsp:include page="header.jsp" /> <% String headerPage = "header.jsp" ; %> <jsp:include page="<%= headerPage %>" />

JSP Predefined Variables request , response , session , application , config , …

More About The JSP Predefined Variables ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More About The JSP Predefined Variables (2) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More About The JSP Predefined Variables (3) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More About The JSP Predefined Variables (4) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Using The application Object ,[object Object],[object Object],[object Object],synchronized (application) { Vector items = (Vector) application.getAttribute ("items"); if (sharedItems == null) { sharedItems = new Vector (); application.setAttribute ("items", items); } }

Using The application Object – Example <%@ page import="java.util.Vector" %> <%// Get the global list of shared items Vector<String> sharedItems; synchronized (application) { sharedItems = (Vector<String>) application.getAttribute ("items"); if (sharedItems == null) { sharedItems = new Vector<String>(); application.setAttribute ("items", sharedItems); } } // Append the new item (if exists) String newItem = request.getParameter("item"); if (newItem != null) sharedItems.addElement(newItem); %>

Using The application Object – Example (2) <html> <head><title>Global Shared List</title></head> <body> Available shared items: <ol> <% for (String item : sharedItems) { %> <li><%= item %></li> <% } %> </ol> <form method="POST" action="Global-Shared-List.jsp"> <input type="text" name="item"> <input type="submit" value="Add"> </form> </body> </html>

Client and Server Redirections

Client Redirection to Another URL ,[object Object],[object Object],[object Object],[object Object],[object Object],response.sendRedirect(<url>); response.sendRedirect("date.jsp");

Server Redirection to Another Resource ,[object Object],[object Object],[object Object],[object Object],request.getRequestDispatcher(<url>). forward(request, response) request.getRequestDispatcher("date.jsp"). forward(request, response);

<jsp:forward> ,[object Object],[object Object],[object Object],<jsp:forward page= {" relativeURL " | "<%= expression %>"} /> <jsp:forward page={" relativeURL " | "<%= expression %>"} > <jsp:param name=" parameterName " value="{ parameterValue | <%= expression %>}" /> </jsp:forward>

<jsp:forward> – Example ,[object Object],[object Object],[object Object],<jsp:forward page="Global-Shared-List.jsp"> <jsp:param name=" item " value= "This item is added by JSP-forward.jsp" /> </jsp:forward>

Escaping Problems And How to Avoid Them

Escaping Problems ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Escaping Problems – Example ,[object Object],[object Object],<html> You entered: <%= request.getParameter("something") %> <form> Enter something:<br> <input type="text" name="something"> <input type="submit"> </form> </html> <script language="JavaScript">alert('Bug!');</script>

What To Escape? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Escape The HTML Special Characters ,[object Object],[object Object]," " Quotation Mark & & Ampersand > > Greater Than < < Less Than Character HTML Entity Character Name       Tab <br> New Line   Space Escaping Character Name

HTML Escaping ,[object Object],[object Object],public static String htmlEscape(String text) { if (text == null) { return ""; } StringBuilder escapedText = new StringBuilder(); for (int i=0; i<text.length(); i++) { char ch = text.charAt(i);

HTML Escaping (2) if (ch == '<') escapedText.append("<"); else if (ch == '>') escapedText.append(">"); else if (ch == '&') escapedText.append("&"); else if (ch == 'amp;quot;') escapedText.append("""); else escapedText.append(ch); } String result = escapedText.toString(); return result; }

Problems ,[object Object],[object Object],[object Object]

Problems (2) ,[object Object],[object Object],[object Object]

Homework ,[object Object],[object Object],[object Object]

Homework (2) ,[object Object],[object Object],[object Object]

Java Server Pages

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Java Server Pages

Similar to Java Server Pages (20)

More from BG Java EE Course

More from BG Java EE Course (20)

Recently uploaded

Recently uploaded (20)

Java Server Pages

Editor's Notes