husted 2004/03/06 18:20:37
Modified: web/example tour.html
Added: web/example base.css
Log:
Migrate tour.html to CSS.
Revision Changes Path
1.3 +23 -22 jakarta-struts/web/example/tour.html
Index: tour.html
===================================================================
RCS file: /home/cvs/jakarta-struts/web/example/tour.html,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- tour.html 7 Mar 2004 01:54:55 -0000 1.2
+++ tour.html 7 Mar 2004 02:20:37 -0000 1.3
@@ -5,13 +5,14 @@
<head>
<meta name="generator" content="HTML Tidy for Windows (vers 1st July 2003), see
www.w3.org" />
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
+ <link rel="stylesheet" type="text/css" href="base.css" />
<title>A Walking Tour of the Struts MailReader Demonstration Application</title>
</head>
<body>
<blockquote>
- <h2><font face="Arial">A Walking Tour of the Struts MailReader Demonstration
Application</font></h2>
+ <h2>A Walking Tour of the Struts MailReader Demonstration Application</h2>
<p><i>This article is meant to introduce a new user to Struts by "walking
through" the example application. See the <a
href="http://jakarta.apache.org/struts/";>Struts Users Guide and Strut's API</a> for
more documentation.</i></p>
@@ -93,7 +94,7 @@
<p>The example is still incomplete, but still a very useful introduction to
Struts. For more about installing Struts and the example application, see the Struts
readme.</p>
- <h3><a name="index.jsp" id="index.jsp"><font
face="Arial">index.jsp</font></a></h3>
+ <h3><a name="index.jsp" id="index.jsp">index.jsp</a></h3>
<p>Once installed, the example application is entered through a standard
welcome page, index.jsp. This page offers two links, one to register with the
application and one to login in (if you have already registered).</p>
@@ -103,7 +104,7 @@
<p><i>Note that the error messages are hardcoded into the welcome page; this
way they can be displayed even if the message resource is missing. In other pages, a
message resource is used to lookup and display messages, based on the user's
locale.</i></p>
</blockquote>
- <h4><font face="Arial"><a name="web.xml" id="web.xml">web.xml</a> and <a
name="ApplicationResources.properties"
id="ApplicationResources.properties">ApplicationResources.properties</a></font></h4>
+ <h4><a name="web.xml" id="web.xml">web.xml</a> and <a
name="ApplicationResources.properties"
id="ApplicationResources.properties">ApplicationResources.properties</a></h4>
<p>If you check the application's web.xml, you will see how these objects are
loaded. The message resource is loaded by the application parameter to the
ActionServlet. When the ActionServlet initializes, it parses the
ApplicationResources.properties in the package folder into the default message
resource. If you change a message in the resource, and then reload the application, it
will appear throughout the application.</p>
@@ -111,7 +112,7 @@
<p><i>You can even reload the configuration and message resources without
restarting the container. See the end of the web.xml file for details.</i></p>
</blockquote>
- <h4><a name="DatabaseServlet.java" id="DatabaseServlet.java"><font
face="Arial">DatabaseServlet.java</font></a></h4>
+ <h4><a name="DatabaseServlet.java"
id="DatabaseServlet.java">DatabaseServlet.java</a></h4>
<p>The database object has it's own initialization block. The database servlet
stores the database contents as a XML file, which is parsed by the Struts digester and
loaded as a set of nested hashtables. The outer table is the list of user objects,
each of which has its own inner hashtable of subscriptions. When you register, a user
object is stored in this hashtable ... and when you login, the user object is stored
within the session context.</p>
@@ -133,7 +134,7 @@
<p><i>In the source to the database servlet, you should notice that the
attribute name for the servlet is read from the package's constant file. This is a
good way to be sure a name or other string value is uniform between source
files.</i></p>
</blockquote>
- <h4><a name="index.jsp_2" id="index.jsp_2"><font face="Arial">index.jsp
2</font></a></h4>
+ <h4><a name="index.jsp_2" id="index.jsp_2">index.jsp 2</a></h4>
<p>Back in the index.jsp, we can find several good uses of Struts custom tags.
Two worth noting now are the base and the link tags. The base tag returns the current
URL to the page, to be sure other relative hyperlinks on the page work properly. The
link tag renders another important service. Besides being a quick way to write a
hyperlink, it will also URL encode the hyperlink to maintain the client's session --
if the current client can't store the session as a cookie.</p>
@@ -155,7 +156,7 @@
<p>At the top of the index.jsp page, you may also note several directives that
load the tag libraries. These are just the usual red tape that goes with any Java
source file.</p>
- <h3><a name="logon.jsp" id="logon.jsp"><font
face="Arial">logon.jsp</font></a></h3>
+ <h3><a name="logon.jsp" id="logon.jsp">logon.jsp</a></h3>
<p>Next, if you choose the log on link, the container loads the logon.jsp file.
You can use the default username and password (user:pass) to login. (Note that both
the username and password are case sensitive.) Better yet, try omitting or misspelling
the login in various combinations and see how the application reacts.</p>
@@ -171,7 +172,7 @@
<p>Pretty cool, but how does it work?</p>
- <h4><font face="Arial"><a name="struts-config.xml"
id="struts-config.xml">struts-config.xml</a> and <a name="LogonForm.java"
id="LogonForm.java">LogonForm.java</a></font></h4>
+ <h4><a name="struts-config.xml" id="struts-config.xml">struts-config.xml</a>
and <a name="LogonForm.java" id="LogonForm.java">LogonForm.java</a></h4>
<p>First, the logon.jsp makes use of the custom-tag "form". This tag can scan
the application's properties for a form bean related to the path /logon.jsp (from the
link on the welcome page). In this case, Struts finds one, and then checks for an
instance of this particular form bean. Not finding one, Struts creates a new form
bean. When the form is submitted, Struts grabs the form fields from the HTTP request,
and updates the waiting bean.</p>
@@ -195,7 +196,7 @@
<p>To get the most out of your form beans, Struts provides a special class,
ActionForm, with built-in support for validation and message handling that you can use
as the base for your own form beans. Each of your JSP forms will probably have a
unique set of fields, and would have their own specific form bean.</p>
- <h4><a name="LogonAction.java" id="LogonAction.java"><font
face="Arial">LogonAction.java</font></a></h4>
+ <h4><a name="LogonAction.java" id="LogonAction.java">LogonAction.java</a></h4>
<p>The initial JSP submits its form to logon.do. If you check the servlet
mappings in the example's web.xml you will see that requests for *.do files are
directed to the Struts "action" servlet (an instance of ActionServlet). In the
example, the ActionServlet refers to struts-config.xml for its own mappings (among
other things), which is where we find the reference to logon.do:</p>
@@ -245,7 +246,7 @@
<p>Go ahead and login successfully now, using the default username and password
(user and pass).</p>
- <h4><a name="struts-config.xml_2" id="struts-config.xml_2"><font
face="Arial">struts-config.xml 2</font></a></h4>
+ <h4><a name="struts-config.xml_2" id="struts-config.xml_2">struts-config.xml
2</a></h4>
<p>As mentioned, on a successful login, LogonAction forwards control to the
"success" action, and where control actually goes is determined by the mappings in
struts-config.xml. But if you check the mappings for LogonAction, you'll find this
block</p>
@@ -292,11 +293,11 @@
<p><i>If you have a sharp eye, you also may have noticed that logon.do is not
followed by any parameters from the login form (logon.do?username=user). The default
method for a from created with the Struts form tag is POST, which does not append form
parameters to the request path, as GET does. This is the opposite of the HTML form
tag, which uses GET by default.</i></p>
</blockquote>
- <h3><a name="mainMenu.jsp" id="mainMenu.jsp"><font
face="Arial">mainMenu.jsp</font></a></h3>
+ <h3><a name="mainMenu.jsp" id="mainMenu.jsp">mainMenu.jsp</a></h3>
<p>If you check the source for mainMenu.jsp, you will find some interesting new
tags. The first is app:checkLogon. This is not a standard Struts custom tag, but one
designed for the Example application. The directive at the top of the file tells us
that the app tags are defined in app.tld. Tracing through app.tld, we find that source
for this tag is (surprise!) CheckLogonTag.</p>
- <h4><a name="CheckLoginTag.java" id="CheckLoginTag.java"><font
face="Arial">CheckLoginTag.java</font></a></h4>
+ <h4><a name="CheckLoginTag.java"
id="CheckLoginTag.java">CheckLoginTag.java</a></h4>
<p>This is an excellent example of using custom tags to encapsulate application
logic. CheckLoginTag.java looks to see if the user is logged in by checking for an
object named "User" in the session context. If not, control is forwarded to
"/login.jsp". So, whenever you want to be sure someone is logged in before they access
a page, just put "<app:checkLogon/>" at the top of the JSP.</p>
@@ -340,7 +341,7 @@
<p><i>Hint: Consistent naming conventions, like the ones used throughout the
Example, make applications much easier to write and understand. Save your creativity
for the things that matter, and follow an established standard for source code
formatting, like the <a href="www.amazon.com/exec/obidos/ISBN=0521777682/">Elements of
Java Style</a>.</i></p>
</blockquote>
- <h4><a name="editRegistrationAction.java"
id="editRegistrationAction.java"><font
face="Arial">EditRegistrationAction.java</font></a></h4>
+ <h4><a name="editRegistrationAction.java"
id="editRegistrationAction.java">EditRegistrationAction.java</a></h4>
<p>Many objects in an application may do double-duty. For example,
EditRegistrationAction not only lets you update a registration, but is also used to
create a new one. Which task the object performs is determined by the action passed to
it. In the case of EditRegistrationAction, it can either edit or create a
registration, the default being create if a task is not specified. To select between
tasks, simply add ?create or ?edit to the hyperlink or form action.</p>
@@ -348,7 +349,7 @@
<p><i>Like most classes in the example application, editRegistration makes
good use of the log to track it's progress. Note that ActionServlet has had a new log
method added since the Example was written. You can now specify both the message and a
minimum logging (or debug) level. For more, see the Javadoc in your
struts-documentation application.</i></p>
</blockquote>
- <h3><font face="Arial"><a name="registration.jsp"
id="registration.jsp">registration.jsp</a> and <a name="RegistrationForm.java"
id="RegistrationForm.java">RegistrationForm.java</a></font></h3>
+ <h3><a name="registration.jsp" id="registration.jsp">registration.jsp</a> and
<a name="RegistrationForm.java"
id="RegistrationForm.java">RegistrationForm.java</a></h3>
<p>If you follow the "Edit your user registration profile" link from the
mainMenu, we will finally reach the heart of the Example application, the registration
page. This page displays everything the Example application knows about you (or at
least your login), while demonstrating several interesting techniques.</p>
@@ -386,7 +387,7 @@
<p>Otherwise, the page just contains the top portion -- a blank data-entry form
for creating the user's registration.</p>
- <h4><a name="logic:iterate" id="logic:iterate"><font
face="Arial">logic:iterate</font></a></h4>
+ <h4><a name="logic:iterate" id="logic:iterate">logic:iterate</a></h4>
<p>Beside making the usual conditional tests, you can also use logic tags to
forward control to other actions, to redirect control to another path, and to iterate
over collections. The registration page includes a good example of using the
logic:iterate tag to display the user's subscriptions.</p>
@@ -455,7 +456,7 @@
<p>You'll note that the hyperlinks to the edit and delete action for each
subscription are written with another custom tag, app:linkSubscription. Writing a
hyperlink to an action is not difficult, but it can be ugly, and makes an excellent
case for encapsulation. If you trace through the app.tld, you will find that the
source code for the linkSubscription tag lives in (<i>come on, take a guess</i>)
LinkSubscriptionTag.java.</p>
- <h4><a name="LinkSubscriptionTag.java" id="LinkSubscriptionTag.java"><font
face="Arial">LinkSubscriptionTag.java</font></a></h4>
+ <h4><a name="LinkSubscriptionTag.java"
id="LinkSubscriptionTag.java">LinkSubscriptionTag.java</a></h4>
<p>The Example application uses a subscription's host name (e.g. yahoo.com) as
a primary key, which means you can only have one subscription for each host. It also
means that to edit a subscription, all you need to know is the user and host. In fact,
the editSubscription action is designed to create, edit, or delete a subscription if
provided a user and host names in the request. The goal of LinkSubscriptionTag is then
to output a block like:</p>
@@ -499,7 +500,7 @@
<p>By this time, you must be ready to flip directly to LinkUserTag.java with
nary a glance at the configuration file ...</p>
- <h4><a name="LinkUserTag.java" id="LinkUserTag.java"><font
face="Arial">LinkUserTag.java</font></a></h4>
+ <h4><a name="LinkUserTag.java" id="LinkUserTag.java">LinkUserTag.java</a></h4>
<p>Since they solve the same general problem, LinkUserTag and
LinkSubscriptionTag are quite a bit a like, except that LinkUserTag grabs the user
bean from the session context, instead of a subscription bean from the iteration. Like
the LinkSubscriptionTag, the name for the user bean (e.g. "user") is defaulted, and
can be omitted from the tag; all that's needed is the page property -- the rest is
automatic!</p>
@@ -521,7 +522,7 @@
<p>Let's follow that "Add" link now and see what's up with the editSubcription
action anyway.</p>
- <h4><a name="EditSubscriptionAction.java"
id="EditSubscriptionAction.java"><font
face="Arial">EditSubscriptionAction.java</font></a></h4>
+ <h4><a name="EditSubscriptionAction.java"
id="EditSubscriptionAction.java">EditSubscriptionAction.java</a></h4>
<p>Predictably, we find a some now-familiar mappings in struts-config.xml</p>
@@ -556,7 +557,7 @@
<p>But before turning to our final JSP, a word about our database model ...</p>
- <h4><font face="Arial"><a name="User.java" id="User.java">User.java</a> and <a
name="Subscription.java" id="Subscription.java">Subscription.java</a></font></h4>
+ <h4><a name="User.java" id="User.java">User.java</a> and <a
name="Subscription.java" id="Subscription.java">Subscription.java</a></h4>
<p>If you're used to working with relational databases, the links between the
user and subscription objects may be confusing. A conventional relational database
would create two distinct tables, one for the users and another for the subscriptions,
and link them together with a user ID. The Example application implements a different
model, a hierarchical database. Here a "table" of subscriptions is stored within each
user object, something like the way a filing system stores documents within
folders.</p>
@@ -564,7 +565,7 @@
<p>To create a new subscription, EditSubscriptionAction.java simply creates a
new subscription object, and sets its user to the object found in the request, and
then forwards control to its input form, subscription.jsp.</p>
- <h3><a name="subcription.jsp" id="subcription.jsp"><font
face="Arial">subscription.jsp</font></a></h3>Saving the best for last,
subscription.jsp demonstrates use of some interesting Struts custom form tags,
html:options and html:checkbox.
+ <h3><a name="subcription.jsp"
id="subcription.jsp">subscription.jsp</a></h3>Saving the best for last,
subscription.jsp demonstrates use of some interesting Struts custom form tags,
html:options and html:checkbox.
<p>In registration.jsp, the Struts iteration tag was used to write a list of
subscriptions. Another place where iterations and collections are handy is the option
list for a HTML select tag. Since this is such a common situation, Struts offers a
html:options (plural) tag can take an array of objects as a parameter. The tag then
iterates over the members of the array (beans) to place each one inside an standard
option tag. So given a block like</p>
@@ -597,7 +598,7 @@
<p>A particularly tricky HTML control is the checkbox. A problem with a
checkbox is that it is only sent in the request if it is checked. If it is not
checked, it is not sent (i.e. null). This can be problematic when trying to validate
the form's data after it has been translated to a bean. The autoconnect property for a
subscription demonstrates how to handle validation of a checkbox.</p>
- <h4><a name="SubscriptionForm.java" id="SubscriptionForm.java"><font
face="Arial">SubscriptionForm.java</font></a></h4>
+ <h4><a name="SubscriptionForm.java"
id="SubscriptionForm.java">SubscriptionForm.java</a></h4>
<p>Struts validation is handled by the reset and validate methods of the
ActionForm bean. When creating your own form beans, you should subclass ActionForm,
add your own fields and their getters/setters, and implement the reset and validate
methods.</p>
@@ -624,13 +625,13 @@
<p>The actual action property is placed into the form as a hidden field, and
SaveSubscriptionAction checks that property to execute the appropriate task.</p>
- <h4><a name="SaveSubscriptionAction.java"
id="SaveSubscriptionAction.java"><font
face="Arial">SaveSubscriptionAction.java</font></a></h4>
+ <h4><a name="SaveSubscriptionAction.java"
id="SaveSubscriptionAction.java">SaveSubscriptionAction.java</a></h4>
<p>Our final stop has the job of finishing what EditSubscriptionAction.java and
subscription.jsp started. After the usual logic and error checking,
SaveSubscriptionAction either deletes or updates the subscription object being handled
by this request, and cleans up the bean, just to be tidy. By now, you should be very
comfortable reading through the source on your own, to pickup the finer points.</p>
<p>This concludes our tour. To review, you may wish to trace the path a new
user takes when they register with the application for the first time. You should also
read over each of the .java and JSP files carefully, since we only covered the high
points here.</p>
- <h3><a name="Summary" id="Summary"><font face="Arial">Summary</font></a></h3>
+ <h3><a name="Summary" id="Summary">Summary</a></h3>
<ul>
<li>Struts uses a single controller servlet to route HTTP requests.</li>
1.1 jakarta-struts/web/example/base.css
Index: base.css
===================================================================
/**
* Base stylesheet
* @version $Revision: 1.1 $ $Date: 2004/03/07 02:20:37 $
*/
body {
background-color:#FFFFFF;
color:#000000;
link:000066;
visited:#660066;
active:#33CCCC;
}
A:hover { color: #FF0000; }
h1 { font-family: Arial,Helvetica,sans-serif; }
h2 { font-family: Arial,Helvetica,sans-serif; }
h3 { font-family: Arial,Helvetica,sans-serif; }
h4 { font-family: Arial,Helvetica,sans-serif; }
h5 { font-family: Arial,Helvetica,sans-serif; }
h6 { font-family: Arial,Helvetica,sans-serif; }
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