What is ActionForm?
An ActionForm is a JavaBean
that extends org.apache.struts.action.ActionForm. ActionForm maintains the session state for web application
and the ActionForm object is automatically populated
on the server side with data entered from a form on the client side.
What is Struts Validator Framework?
Struts Framework provides the functionality to validate the form
data. It can be use to validate the data on the users browser as well as on the
server side. Struts Framework emits the java scripts and it can be used
validate the form data on the client browser. Server side validation of form
can be accomplished by sub classing your From Bean with DynaValidatorForm
class. The Validator framework was developed by David
Winterfeldt as third-party add-on to Struts. Now the Validator framework is a part of Jakarta
Commons project and it can be used with or without Struts. The Validator framework comes integrated with the Struts
Framework and can be used without doing any extra settings.
Give the Details of XML files used in Validator Framework?
The Validator Framework uses two XML configuration
files validator-rules.xml and validation.xml. The validator-rules.xml defines
the standard validation routines, these are reusable and used in
validation.xml. to define the form specific
validations. The validation.xml defines the validations applied to a form bean.
How you will display validation fail errors on jsp
page? - The following tag displays all the errors: < html:errors/ >
Why do we need Struts?
Java technologies give developers a serious boost when creating
and maintaining applications to meet the demands of today's public Web sites
and enterprise intranets. Struts combines Java Servlets, Java ServerPages,
custom tags, and message resources into a unified framework. The end result is
a cooperative, synergistic platform, suitable for development teams,
independent developers, and everyone in between.
How does Struts work?
Java Servlets are designed to handle requests made by
Web browsers. Java ServerPages are designed to create
dynamic Web pages that can turn billboard sites into live applications. Struts uses a special Servlet as a
switchboard to route requests from Web browsers to the appropriate ServerPage. This makes Web applications much easier to
design, create, and maintain.
Is Struts compatible with
other Java technologies?
Yes. Struts is committed to supporting industry
standards. Struts acts as an integrator of Java technologies so that they can
be used in the "real world".
Who wrote Struts?
There are several active committers to the Struts project, working
cooperatively from around the globe. Dozens of individual developers and
committers contributed to the Struts 1.x codebase. All interested Java
developers are invited to contribute to the project. Struts is a Apache
Software Foundation project, with the mission to "provide secure,
enterprise-grade server solutions based on the Java Platform that are developed
in an open and cooperative fashion".
Struts was created by Craig R. McClanahan and donated to The Apache Software
Foundation in May 2000. Craig was the primary developer of both Struts 1.x and
Tomcat 4. Tomcat 4 was the basis for the official reference implementation for
a servlet 2.3 and JSP 1.2 container.
Craig's current focus is as architect of the Sun Java Studio Creator (formerly
Project Rave). Craig also serves as the Specification Lead for JavaServer Faces (JSR-127), and is the Web Layer Architect
for the Java2 Enterprise Edition (J2EE) platform as a whole.
Why is it called Struts?
It's a reference to struts in the architectural sense, a reminder
of the nearly invisible pieces that hold up buildings, houses, and bridges.
Do I have to credit Struts on my own
website?
You need to credit Struts if you redistribute your own framework based on
Struts for other people to use. (See the Apache License for details.) But you
do not need to credit Struts just because your web application utilizes the
framework. It's the same situation as using the Apache HTTPD server or Tomcat.
Not required if its just running your web site.
Where can I get a copy of Struts?
The best place to download Struts is at struts.apache.org. The nightly builds
are very stable, and recommended as the best place to start today.
How do I install Struts?
To develop applications with Struts, you can usually just add the Struts JAR
file to your Java development environment. You can then start using the Struts
classes as part of your own application. A blank Struts application (in the webapps directory, open struts-blank.war) is provided,
which you can just copy to get a quick-start on your own brainchild.
Since the full source code for Struts is available, we also provide complete
instructions for compiling your own Struts JAR from scratch. (This is actually
easier than it looks!)
Your Struts application can usually be deployed using a standard WAR file. In
most cases, you simply deposit the WAR file on your application server, and it
is installed automatically. If not, step-by-step installation instructions for
various servlet containers are available.
When do I need "struts.jar" on
my classpath?
When you are compiling an application that uses the Struts classes, you must
have the "struts.jar" on the classpath your
compiler sees -- it does not have to be on your CLASSPATH environment variable.
Why is that an important distinction? Because if you are using a servlet container on your development machine to test your
application, the "struts.jar" must not be on your CLASSPATH
environment variable when running the container. (This is because each Web
application must also have their own copy of the Struts classes, and the
container will become confused if it is on the environment path as well.)
There are several general approaches to this issue:
* Use ANT for building your projects -- it can easily assemble classpaths for the compiler. (This is how Struts itself is
built, along with Tomcat and most other Java-based projects).
* Use an IDE where you can configure the "class path" used for
compilation independent of the CLASSPATH environment variable.
* Use a shell script that temporarily adds struts.jar to the classpath just for compilation, for example javac -classpath
/path/to/struts.jar:$CLASSPATH $@
Does Struts include its own unit tests?
Struts currently has two testing environments, to reflect the fact that some
things can be tested statically, and some really need to be done in the
environment of a running servlet container.
For static unit tests, we use the JUnit framework.
The sources for these tests are in the "src/test"
hierarchy in the source repository, and are executed via the "test.junit" target in the top-level build.xml file.
Such tests are focused on the low-level functionality of individual methods,
are particularly suitable for the static methods in the org.apache.struts.util
utility classes. In the test hierarchy, there are also some "mock
object" classes (in the org.apache.struts.mock
package) so that you can package up things that look like servlet
API and Struts API objects to pass in as arguments to such tests.
Another valuable tool is Struts TestCase which
provides a useful harness for Action classes that can be used with JUnit or Cactus.
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