CSCI A348/548
Lecture Notes Twenty-Two

Spring 2001 (Second semester 2000-2001)

Java Server Pages (JSP) This also serves as lab notes 11.

I'm starting these notes today and I am sure I won't be able to finish them today. But starting them off is better than waiting until a time when I can write them completely in one sitting, so expect these notes (as well as any of the notes posted this week and the one before) to change between now and the end of the semester. These are working notes. The book we are working with at this point is Marty Hall's Core Servlets and Java Server Pages (here).

JSP provides a convenient alternative to servlets for pages that most consist of fixed content.

Here's an overview of the Java Server Pages section of the book:

JSP Scripting Elements
The JSP page directive: Structuring Generated Servlets
Including Files and Applets in JSP Documents
Using JavaBeans with JSP
Creating Custom JSP Tag Libraries
Integrating Servlets and JSP

We also have a third part: Supporting Technologies

HTML Forms
Applets Talking to Servlets
JDBC (Java DataBase Connectivity)

These last three will most likely have to wait until next week.

Now let's put together some examples.

I already have the introduction from last year.

Aside from the regular HTML, three are the main types of JSP constructs that you embed in a page:

scripting elements
directives, and
actions

The lab from last year takes care of the first of these constructs.

The process of making Java Server Pages accessible on the Web is much simpler than that for servlets. Assuming you have a Web server that supports JSP (such as Tomcat), you give your file a .jsp extension and simply install it in any place you could put a normal Web page. Let's try this out: create a directory March in your Tomcat for all the JSP files and place the files there.

Example 1. Expressions.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of JSP Expressions. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>JSP Expressions</TITLE>
<META NAME="author" CONTENT="Marty Hall">
<META NAME="keywords"
      CONTENT="JSP,expressions,JavaServer,Pages,servlets">
<META NAME="description"
      CONTENT="A quick example of JSP expressions.">
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>
<H2>JSP Expressions</H2>
<UL>
  <LI>Current time: <%= new java.util.Date() %>
  <LI>Your hostname: <%= request.getRemoteHost() %>
  <LI>Your session ID: <%= session.getId() %>
  <LI>The <CODE>testParam</CODE> form parameter:
      <%= request.getParameter("testParam") %>
</UL>
</BODY>
</HTML>

You also need this style sheet in the same directory:

<STYLE TYPE="text/css">
<!--
BODY { background-color: #FDF5E6 }
A:hover { color: red }
H1 { color: #440000;
     text-align: center;
     font-family: Arial Black, Arial, Helvetica, sans-serif
}
H2 { color: #440000;
     text-align: left;
     font-family: Arial, Helvetica, sans-serif
}
H3 { color: #440000;
     text-align: left;
     font-family: Arial, Helvetica, sans-serif
}
UL { margin-top: 0;
     border-top-width: 0;
     padding-top: 0
}
DT { font-weight: bold;
}
PRE { font-size: 105%;
}
CODE { font-size: 105%; 
}
.TOC { font-size: 90%;
       font-weight: bold;
       font-family: Arial, Helvetica, sans-serif
}
TH.COLORED { background-color: #FFAD00
}
TR.COLORED { background-color: #FFAD00
}
TH.TITLE   { background-color: #EF8429;
             font-size: 28px;
             font-family: Arial, Helvetica, sans-serif;
}
-->
</STYLE>

Call it JSP-Styles.css and place it next in March.

Then try the top JSP page over the web: here.

Example 2. BGColor.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!--    
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
  <TITLE>Color Testing</TITLE>
</HEAD>

<%
String bgColor = request.getParameter("bgColor");
boolean hasExplicitColor;
if (bgColor != null) {
  hasExplicitColor = true;
} else {
  hasExplicitColor = false;
  bgColor = "WHITE";
}
%>
<BODY BGCOLOR="<%= bgColor %>">
<H2 ALIGN="CENTER">Color Testing</H2>

<%
if (hasExplicitColor) {
  out.println("You supplied an explicit background color of " +
              bgColor + ".");
} else {
  out.println("Using default background color of WHITE. " +
              "Supply the bgColor request attribute to try " +
              "a standard color, an RRGGBB value, or to see " +
              "if your browser supports X11 color names.");
}
%>

</BODY>
</HTML>

Check it on-line here (or here). What is the difference?

Example 3. Greetings.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!--   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Greetings</TITLE>
</HEAD>

<BODY>
<H2>Greetings</H2>

<% if (Math.random() < 0.5) { %>
Have a <B>nice</B> day!
<% } else { %>
Have a <B>lousy</B> day!
<% } %>

</BODY>
</HTML>

Then try it on-line over the web from here.

Example 4. AccessCounts.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!--   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>JSP Declarations</TITLE>
<META NAME="author" CONTENT="Marty Hall">
<META NAME="keywords"
      CONTENT="JSP,declarations,JavaServer,Pages,servlets">
<META NAME="description"
      CONTENT="A quick example of JSP declarations.">
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>
<H1>JSP Declarations</H1>

<%! private int accessCount = 0; %>
<H2>Accesses to page since server reboot: 
<%= ++accessCount %></H2>

</BODY>
</HTML>

Then try it on-line over the web from here.

Essentially we looked at scripting elements above:

expressions
scriptlets
declarations

The remaining examples look at:

directives and
actions

A JSP directive affects the overall structure of the servlet that results from the JSP page.

There are three types of directives:

page
include
taglib

We first look at page.

Example 5. ContentType.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>The contentType Attribute</TITLE>
</HEAD>
<BODY>

<H2>The contentType Attribute</H2>
<%@ page contentType="text/plain" %>
This should be rendered as plain text,
<B>not</B> as HTML.

</BODY>
</HTML>

Then try it on-line over the web from here.

Example 6. Excel.jsp

<%@ page contentType="application/vnd.ms-excel" %>
<%-- Note that there are tabs, not spaces, between columns. --%>
1997    1998    1999    2000    2001 (Anticipated)
12.3    13.4    14.5    15.6    16.7

Then try it on-line over the web from here.

Example 7. ApplesAndOranges.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Comparing Apples and Oranges</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>
<CENTER>
<H2>Comparing Apples and Oranges</H2>

<% 
String format = request.getParameter("format");
if ((format != null) && (format.equals("excel"))) { 
  response.setContentType("application/vnd.ms-excel");
}  
%>

<TABLE BORDER=1>
  <TR><TH></TH><TH>Apples<TH>Oranges
  <TR><TH>First Quarter<TD>2307<TD>4706
  <TR><TH>Second Quarter<TD>2982<TD>5104
  <TR><TH>Third Quarter<TD>3011<TD>5220
  <TR><TH>Fourth Quarter<TD>3055<TD>5287
</TABLE>

</CENTER>
</BODY>
</HTML>

Then try it on-line over the web from here.

Example 8. ComputeSpeed.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of using error pages (e.g. when divide by zero
or number format exception occurs on this page). 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Computing Speed</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<%@ page errorPage="SpeedErrors.jsp" %>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Computing Speed</TABLE>

<%! 
// Note lack of try/catch for NumberFormatException if
// value is null or malformed.

private double toDouble(String value) {
  return(Double.valueOf(value).doubleValue());
}
%>

<% 
double furlongs = toDouble(request.getParameter("furlongs")); 
double fortnights = toDouble(request.getParameter("fortnights"));
double speed = furlongs/fortnights;
%>

<UL>
  <LI>Distance: <%= furlongs %> furlongs.
  <LI>Time: <%= fortnights %> fortnights.
  <LI>Speed: <%= speed %> furlongs per fortnight.
</UL>

</BODY>
</HTML>

Uses SpeedErrors.jsp listed below:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of an error pages (used with ComputeSpeed.jsp). 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Error Computing Speed</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<%@ page isErrorPage="true" %>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Error Computing Speed</TABLE>
<P>
ComputeSpeed.jsp reported the following error:
<I><%= exception %></I>. This problem occurred in the
following place:
<PRE>
<% exception.printStackTrace(new PrintWriter(out)); %>
</PRE>

</BODY>
</HTML>

Then try it on-line over the web from here.

Now we look at include:

Example 9. SomeRandomPage.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of including files at page translation time. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Some Random Page</TITLE>
<META NAME="author" CONTENT="J. Random Hacker">
<META NAME="keywords"
      CONTENT="foo,bar,baz,quux">
<META NAME="description"
      CONTENT="Some random Web page.">
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>
<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Some Random Page</TABLE>
<P>
Information about our products and services.
<P>
Blah, blah, blah.
<P>
Yadda, yadda, yadda.

<%@ include file="ContactSection.jsp" %>
      
</BODY>
</HTML>

Uses the results produced by ContactSection.jsp:

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

<%-- The following become fields in each servlet that
     results from a JSP page that includes this file. --%>
<%! 
private int accessCount = 0;
private Date accessDate = new Date();
private String accessHost = "<I>No previous access</I>";
%>

<P>
<HR>
This page &copy; 2000 
<A HREF="http//www.my-company.com/">my-company.com</A>.
This page has been accessed <%= ++accessCount %>
times since server reboot. It was last accessed from 
<%= accessHost %> at <%= accessDate %>.

<% accessHost = request.getRemoteHost(); %>
<% accessDate = new Date(); %>

Then try it on-line over the web from here.

Example 10. WhatsNew.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of including files at request time. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>What's New</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<CENTER>
<TABLE BORDER=5>
  <TR><TH CLASS="TITLE">
      What's New at JspNews.com</TABLE>
</CENTER>
<P>

Here is a summary of our four most recent news stories:
<OL>
  <LI><jsp:include page="news/Item1.html" flush="true" />
  <LI><jsp:include page="news/Item2.html" flush="true" />
  <LI><jsp:include page="news/Item3.html" flush="true" />
  <LI><jsp:include page="news/Item4.html" flush="true" />
</OL>
</BODY>
</HTML>

Refers to (for purposes of including) the following files:

Item1.html

<B>Bill Gates acts humble.</B> In a startling and unexpected
development, Microsoft big wig Bill Gates put on an open act of
humility yesterday.
<A HREF="http://www.microsoft.com/Never.html">More details...</A>

Item2.html

<B>Scott McNealy acts serious.</B> In an unexpected twist, 
wisecracking Sun head Scott McNealy was sober and subdued at 
yesterday's meeting.
<A HREF="http://www.sun.com/Imposter.html">More details...</A>

Item3.html

<B>Larry Ellison acts conciliatory.</B> Catching his competitors 
off guard yesterday, Oracle prez Larry Ellison referred to his 
rivals in friendly and respectful terms.
<A HREF="http://www.oracle.com/Mistake.html">More details...</A>

Item4.html

<B>Sportscaster uses "literally" correctly.</B> In an apparent 
slip of the tongue, a popular television commentator was 
heard to use the word "literally" when he did <I>not</I> 
mean "figuratively."
<A HREF="http://www.espn.com/Slip.html">More details...</A>

Notice that each of these files needs to be placed in March/news.

Then try it on-line over the web from here.

Using JavaBeans with JSP

Full coverage of JavaBeans:

http://java.sun.com/beans/docs

For our purposes we only need to remember that:

A bean class must have a zero-argument (empty, no-args) constructor.
A bean class should have no public instance variables (fields).
Persistent values should be accessed through methods called:
- getPropertyName and
- setPropertyName
The bean will be assumed to have a property propertyName (notice the change of case).

Here's a simple bean:

package coreservlets;

/** A simple bean that has a single String property
 *  called message.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  &copy; 2000 Marty Hall; may be freely used or adapted.
 */

public class StringBean {
  private String message = "No message specified";

  public String getMessage() {
    return(message);
  }

  public void setMessage(String message) {
    this.message = message;
  }
}

It has a String property called message.

Example 11. StringBean.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Simple example of jsp:useBean and manipulating properties
with jsp:setProperty and jsp:getProperty and
with explicit Java code in scriptlets and expressions. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Using JavaBeans with JSP</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Using JavaBeans with JSP</TABLE>
 
<jsp:useBean id="stringBean" class="coreservlets.StringBean" />

<OL>
<LI>Initial value (getProperty):
    <I><jsp:getProperty name="stringBean" 
                        property="message" /></I>

<LI>Initial value (JSP expression):
    <I><%= stringBean.getMessage() %></I>
<LI><jsp:setProperty name="stringBean" 
                     property="message" 
                     value="Best string bean: Fortex" />
    Value after setting property with setProperty:
    <I><jsp:getProperty name="stringBean" 
                        property="message" /></I>

<LI><% stringBean.setMessage("My favorite: Kentucky Wonder"); %>
    Value after setting property with scriptlet:
    <I><%= stringBean.getMessage() %></I>
</OL>
             
</BODY>
</HTML>

Then try it on-line over the web from here.

The next three examples work with the following bean:

package coreservlets;

/** Simple bean to illustrate the various forms
 *  of jsp:setProperty.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  &copy; 2000 Marty Hall; may be freely used or adapted.
 */

public class SaleEntry {
  private String itemID = "unknown";
  private double discountCode = 1.0;
  private int numItems = 0;

  public String getItemID() {
    return(itemID);
  }

  public void setItemID(String itemID) {
    if (itemID != null) {
      this.itemID = itemID;
    } else {
      this.itemID = "unknown";
    }
  }

  public double getDiscountCode() {
    return(discountCode);
  }

  public void setDiscountCode(double discountCode) {
    this.discountCode = discountCode;
  }

  public int getNumItems() {
    return(numItems);
  }

  public void setNumItems(int numItems) {
    this.numItems = numItems;
  }
  
  // Replace this with real database lookup.
  
  public double getItemCost() {
    double cost;
    if (itemID.equals("a1234")) {
      cost = 12.99*getDiscountCode();
    } else {
      cost = -9999;
    }
    return(roundToPennies(cost));
  }

  private double roundToPennies(double cost) {
    return(Math.floor(cost*100)/100.0);
  }

  public double getTotalCost() {
    return(getItemCost() * getNumItems());
  }
}

Example 12.1 SaleEntry1.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of using jsp:setProperty with an explicit value
supplied to the "value" attribute. See SaleEntry2.jsp
and SaleEntry3.jsp for alternatives. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Using jsp:setProperty</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Using jsp:setProperty</TABLE>

<jsp:useBean id="entry" class="coreservlets.SaleEntry" />

<jsp:setProperty 
    name="entry" 
    property="itemID"
    value='<%= request.getParameter("itemID") %>' />
    
<%
int numItemsOrdered = 1;
try {
  numItemsOrdered = 
    Integer.parseInt(request.getParameter("numItems"));
} catch(NumberFormatException nfe) {}
%>
<jsp:setProperty 
    name="entry" 
    property="numItems"
    value="<%= numItemsOrdered %>" />

<% 
double discountCode = 1.0;
try {
  String discountString = 
    request.getParameter("discountCode");
  // Double.parseDouble not available in JDK 1.1.
  discountCode = 
    Double.valueOf(discountString).doubleValue();
} catch(NumberFormatException nfe) {}
%>
<jsp:setProperty 
    name="entry" 
    property="discountCode"
    value="<%= discountCode %>" />

<BR>
<TABLE ALIGN="CENTER" BORDER=1>
<TR CLASS="COLORED">
  <TH>Item ID<TH>Unit Price<TH>Number Ordered<TH>Total Price
<TR ALIGN="RIGHT">
  <TD><jsp:getProperty name="entry" property="itemID" />
  <TD>$<jsp:getProperty name="entry" property="itemCost" />
  <TD><jsp:getProperty name="entry" property="numItems" />
  <TD>$<jsp:getProperty name="entry" property="totalCost" />
</TABLE>
             
</BODY>
</HTML>

Then try it on-line over the web from here.

(Read the warning in the code below first).

Example 12.2 SaleEntry2.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of using jsp:setProperty and an explicity association
with an input parameter. See SaleEntry1.jsp
and SaleEntry3.jsp for alternatives. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Using jsp:setProperty</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Using jsp:setProperty</TABLE>

<jsp:useBean id="entry" class="coreservlets.SaleEntry" />

<jsp:setProperty 
    name="entry"
    property="itemID"
    param="itemID" />
    
<jsp:setProperty 
    name="entry"
    property="numItems"
    param="numItems" />
    
<%-- WARNING! Both the JSWDK 1.0.1 and the Java Web Server
              have a bug that makes them fail on double
              type conversions of the following sort.
--%>
<jsp:setProperty 
    name="entry"
    property="discountCode"
    param="discountCode" />

<BR>
<TABLE ALIGN="CENTER" BORDER=1>
<TR CLASS="COLORED">
  <TH>Item ID<TH>Unit Price<TH>Number Ordered<TH>Total Price
<TR ALIGN="RIGHT">
  <TD><jsp:getProperty name="entry" property="itemID" />
  <TD>$<jsp:getProperty name="entry" property="itemCost" />
  <TD><jsp:getProperty name="entry" property="numItems" />
  <TD>$<jsp:getProperty name="entry" property="totalCost" />
</TABLE>
             
</BODY>
</HTML>

Then try it on-line over the web from here.

Example 12.3 SaleEntry3.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of using jsp:setProperty and a general association
with the input parameters. See SaleEntry1.jsp
and SaleEntry2.jsp for alternatives. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Using jsp:setProperty</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Using jsp:setProperty</TABLE>

<jsp:useBean id="entry" class="coreservlets.SaleEntry" />
<%-- WARNING! Both the JSWDK 1.0.1 and the Java Web Server
              have a bug that makes them fail on automatic
              type conversions to double values.
--%>
<jsp:setProperty name="entry" property="*" />

<BR>
<TABLE ALIGN="CENTER" BORDER=1>
<TR CLASS="COLORED">
  <TH>Item ID<TH>Unit Price<TH>Number Ordered<TH>Total Price
<TR ALIGN="RIGHT">
  <TD><jsp:getProperty name="entry" property="itemID" />
  <TD>$<jsp:getProperty name="entry" property="itemCost" />
  <TD><jsp:getProperty name="entry" property="numItems" />
  <TD>$<jsp:getProperty name="entry" property="totalCost" />
</TABLE>
             
</BODY>
</HTML>

Then try it on-line over the web from here.

Next three examples use this same bean:

package coreservlets;

/** Simple bean to illustrate sharing beans through
 *  use of the scope attribute of jsp:useBean.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  &copy; 2000 Marty Hall; may be freely used or adapted.
 */

public class AccessCountBean {
  private String firstPage;
  private int accessCount = 1;

  public String getFirstPage() {
    return(firstPage);
  }

  public void setFirstPage(String firstPage) {
    this.firstPage = firstPage;
  }

  public int getAccessCount() {
    return(accessCount++);
  }
}

Example 13.1 SharedCounts1.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of sharing beans. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Shared Access Counts: Page 1</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Shared Access Counts: Page 1</TABLE>
<P>
<jsp:useBean id="counter" 
             class="coreservlets.AccessCountBean"
             scope="application">
  <jsp:setProperty name="counter" 
                   property="firstPage"
                   value="SharedCounts1.jsp" />
</jsp:useBean>

Of SharedCounts1.jsp (this page), 
<A HREF="SharedCounts2.jsp">SharedCounts2.jsp</A>, and
<A HREF="SharedCounts3.jsp">SharedCounts3.jsp</A>, 
<jsp:getProperty name="counter" property="firstPage" />
was the first page accessed.
<P>
Collectively, the three pages have been accessed 
<jsp:getProperty name="counter" property="accessCount" />
times.
             
</BODY>
</HTML>

Then try it on-line over the web from here.

Example 13.2 SharedCounts2.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of sharing beans. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Shared Access Counts: Page 2</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Shared Access Counts: Page 2</TABLE>
<P>
<jsp:useBean id="counter" 
             class="coreservlets.AccessCountBean"
             scope="application">
  <jsp:setProperty name="counter" 
                   property="firstPage"
                   value="SharedCounts2.jsp" />
</jsp:useBean>

Of SharedCounts2.jsp (this page), 
<A HREF="SharedCounts1.jsp">SharedCounts1.jsp</A>, and
<A HREF="SharedCounts3.jsp">SharedCounts3.jsp</A>, 
<jsp:getProperty name="counter" property="firstPage" />
was the first page accessed.
<P>
Collectively, the three pages have been accessed 
<jsp:getProperty name="counter" property="accessCount" />
times.
             
</BODY>
</HTML>

Then try it on-line over the web from here.

Example 13.3 SharedCounts3.jsp

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- 
Example of sharing beans. 
   
Taken from Core Servlets and JavaServer Pages
from Prentice Hall and Sun Microsystems Press,
http://www.coreservlets.com/.
&copy; 2000 Marty Hall; may be freely used or adapted.
-->
<HTML>
<HEAD>
<TITLE>Shared Access Counts: Page 3</TITLE>
<LINK REL=STYLESHEET
      HREF="JSP-Styles.css"
      TYPE="text/css">
</HEAD>

<BODY>

<TABLE BORDER=5 ALIGN="CENTER">
  <TR><TH CLASS="TITLE">
      Shared Access Counts: Page 3</TABLE>
<P>
<jsp:useBean id="counter" 
             class="coreservlets.AccessCountBean"
             scope="application">
  <jsp:setProperty name="counter" 
                   property="firstPage"
                   value="SharedCounts3.jsp" />
</jsp:useBean>

Of SharedCounts3.jsp (this page), 
<A HREF="SharedCounts1.jsp">SharedCounts1.jsp</A>, and
<A HREF="SharedCounts2.jsp">SharedCounts2.jsp</A>, 
<jsp:getProperty name="counter" property="firstPage" />
was the first page accessed.
<P>
Collectively, the three pages have been accessed 
<jsp:getProperty name="counter" property="accessCount" />
times.
             
</BODY>
</HTML>

Then try it on-line over the web from here.

Example 14. One.jsp

Then try it on-line over the web from here.

Last updated on Mar 29, 2001, by Adrian German for A348/A548

CSCI A348/548 Lecture Notes Twenty-Two

CSCI A348/548
Lecture Notes Twenty-Two