java server pages creating dynamic web pages using java
Download
Skip this Video
Download Presentation
JAVA SERVER PAGES CREATING DYNAMIC WEB PAGES USING JAVA

Loading in 2 Seconds...

play fullscreen
1 / 30

JAVA SERVER PAGES CREATING DYNAMIC WEB PAGES USING JAVA - PowerPoint PPT Presentation


  • 155 Views
  • Uploaded on

JAVA SERVER PAGES CREATING DYNAMIC WEB PAGES USING JAVA. James Faeldon CS 119 Enterprise Systems Programming. Overview. Introduction to JSP Understanding the need for JSP Evaluating the benefits of JSP Installing JSP Files JSP Scripting Elements JSP Expressions JSP Scriplets

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' JAVA SERVER PAGES CREATING DYNAMIC WEB PAGES USING JAVA' - vielka-diaz


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
java server pages creating dynamic web pages using java

JAVA SERVER PAGESCREATING DYNAMIC WEB PAGES USING JAVA

James Faeldon

CS 119 Enterprise Systems Programming

overview
Overview
  • Introduction to JSP
    • Understanding the need for JSP
    • Evaluating the benefits of JSP
    • Installing JSP Files
  • JSP Scripting Elements
    • JSP Expressions
    • JSP Scriplets
    • JSP Declarations
  • JSP Page Directive
    • Understanding the purpose of the page directive
    • Designating which classes are imported
    • Specifying the MIME type of the page
introduction to jsp
Introduction to JSP
  • Java Server Pages (JSP) technology enables you to mix regular, static HTML with dynamically generated content.

OrderConfirmation.jsp

introduction to jsp1
Introduction to JSP
  • Dynamic Pages can change in response to different context or conditions.

HTTP request parameters used as dynamic content

servlets vs jsp
Servlets vs. JSP
  • Servletsare good for data processing while JSP is good for presentation.
  • Benefits of JSP
    • It is easier to write and maintain the HTML
    • You can use standard Web-site development tools
    • You can divide up your development team
reading 3 parameters example
Reading 3 Parameters (Example)

SERVLET

HTML code in JAVA

JSP

JAVA code in HTML

ThreeParams.java

ThreeParams.jsp

servlets vs jsp1
Servlets vs. JSP
  • JSP doesn’t provide any capabilities that couldn’t be accomplished with Servlets.
  • JSP documents are automatically translated into servlets behind the scenes.
  • The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other.
  • Choose the right tool for the job.
installation of jsp files
Installation of JSP files

JSP Directories for Tomcat

  • Main Location:

tomcat_install_dir/webapps/ROOT

  • Corresponding URL:

http://localhost:8080/SomeFile.jsp

  • More Specific Location (Arbitrary Subdirectory):

tomcat_install_dir/webapps/ROOT/SomeDirectory

  • Corresponding URL:

http://localhost:8080/SomeDirectory/SomeFile.jsp

types of jsp scripting elements
Types of JSP Scripting Elements
  • Expressions of the form <%= Java Expression %>, which are evaluated and inserted into the servlet’s output.
  • Scriptletsof the form <% Java Code %>, which are inserted into the servlet’s _jspService method (called by service).
  • Declarations of the form <%! Field/Method Declaration %>, which are inserted into the body of the servlet class, outside any existing methods.
using jsp expressions
Using JSP Expressions

A JSP expression is used to insert values directly into the output. It has the following form:

<%= Java Expression %>

Example:

Current time: <%= new java.util.Date() %>

predefined variables
Predefined Variables
  • request, the HttpServletRequest.
  • response, the HttpServletResponse.
  • session, the HttpSession associated with the request (unless disabled with the session attribute of the page directive
  • out, the Writer (a buffered version of type JspWriter) used to send output to the client.
  • application, the ServletContext. This is a data structure shared by all servlets and JSP pages in the Web application and is good for storing shared data.

Example:

Your hostname: <%= request.getRemoteHost() %>

writing jsp scriplets
Writing JSP Scriplets

If you want to do something more complex than output the value of a simple expression, JSP scriptlets let you insert arbitrary code. It has the following form:

<% Java Code %>

Example:

<%

String queryData = request.getQueryString();

out.println("Attached GET data: " + queryData);

%>

using jsp declarations
Using JSP Declarations

A JSP declaration lets you define methods or fields that get inserted into the main body of the servlet class. It has the following form:

<%! Field or Method Definition %>

Example:

<H1>Some Heading</H1>

<%!

private String randomHeading() {

return("<H2>" + Math.random() + "</H2>");

}

%>

<%= randomHeading() %>

jsp directive
JSP Directive
  • A JSP Directive affects the overall structure of the JSP page. It has the form:

<%@ directive attribute="value" %>

<%@ directive attribute1="value1"

attribute2="value2"

...

attributeN="valueN" %>

  • There are three main types of directives: page, include andtaglib.
the import attribute
The import Attribute

The import attribute of the page directive lets you specify the packages that should be imported into the JSP page.

<%@ page import="package.class" %>

<%@ page import="package.class1,...,package.classN" %>

Example:

<%@ page import="java.util.*" %>

Date today: <%= new Date() %>

the contenttype attribute
The contentType Attribute
  • The contentType attribute sets the Content-Type response header, indicating the MIME type of the document being sent to the client.
  • Use of the contentType attribute takes one of the following two forms.

<%@ page contentType="MIME-Type" %>

<%@ page contentType="MIME-Type; charset=Character-Set" %>

Example:

First Last Email Address

James Gosling [email protected]

Larry Brown [email protected]

Steve Balmer [email protected]

Scott McNealy [email protected]

<%@ page contentType="application/vnd.ms-excel" %>

<%-- There are tabs, not spaces, between columns. --%>

strategies for invoking dynamic code in jsp
Strategies for invoking dynamic code in JSP
  • Call Java code directly.Place all Java code in JSP page. Appropriate only for very small amounts of code.
  • Call Java code indirectly.Develop separate utility classes. Insert into JSP page only the Java code needed to invoke the utility classes.
  • Use beans. Develop separate utility classes structured as beans. Use jsp:useBean, jsp:getProperty, and jsp:setProperty to invoke the code.
  • Use the MVC architecture. Have a servlet respond tooriginal request, look up data, and store results in beans.Forward to a JSP page to present results. JSP page uses beans.
  • Use the JSP expression language. Use shorthand syntax to access and output object properties. Usually used in conjunction with beans and MVC.
  • Use custom tags. Develop tag handler classes. Invoke the taghandlers with XML-like custom tags.
slide29
Tips
  • Limit the amount of Java code that is in JSP pages. At the very least, use helper classes that are invoked from the JSP pages.
  • Put all your classes in packages.
  • Define most methods with separate Java classes, not JSP declarations.
exercise
Exercise:

Create a web page that will display the contents of the PERSON table in the owners database.

You should be able to display the records in an HTML table or in an Excel spreadsheet.

Note: If your browser does not support displaying Excel spreadsheet a prompt will show just choose to open the file.

ad