22-GuideBuidlingStrutsApp36

7/28/2019 22-GuideBuidlingStrutsApp36

1/36

1

1

Step by Step Guidefor building a simple

Struts Application

In this session, we will try to build a very simple Struts applicationstep by step.

2/30/2006


2/36

2

2

Sang Shin

[email protected]/j2ee

Java

Technology EvangelistSun Microsystems, Inc.

2/30/2006


3/36

3

3

Sample App We aregoing to build

2/30/2006


4/36

4

4

Sample App? Keld Hansen's submit application

? Things to do

Creating ActionForm object

Creating Action object

Forwarding at either success or failure throughconfiguration set in struts-config.xml file

Input validation

Internationalizaition

? You can also build it using NetBeans

The sample application we are going to use and show is Keld Hansen'ssubmit application. The source files and ant build.xml script can be foundin the handson/homework material you can download from class website.

This is a simple application but it uses most of Struts framework.

2/30/2006


5/36

5

5

Steps to follow

Now let's take a look at the steps you will follow.

2/30/2006


6/36

6

6

Steps

1.Create development directory structure

2.Write web.xml

3.Write struts-config.xml

4.Write ActionForm classes

5.Write Action classes

6.Create ApplicationResource.properties

7.Write JSP pages8.Write ant build script

9.Build, deploy, and test the application

So this is the list of steps. Of course, you don't exactly followthese steps in sequence. In fact, it is expected that some of thesesteps will be reiterated.

2/30/2006


7/36

7

7

Step 1: Create DevelopmentDirectory Structure

The first step is to create development directory structure.

2/30/2006


8/36

8

8

Development DirectoryStructure

? Same development directory structure forany typical Web application

? Ant build script should be writtenaccordingly

? If you are using NetBeans, it is taken careof by the IDE

The source directory structure is the same directory structure weused for other Web application development under Java WSDP.Of course, the build.xml script should be written accordingly.

2/30/2006


9/36

9

9

Step 2: Write web.xmlDeployment Descriptor

Step 2 is to write web.xml file.

2/30/2006


10/36

10

10

web.xml? Same structure as any other Web

application

ActionServlet is like any other servlet

Servlet definition and mapping of ActionServlet

? There are several Struts specific elements

? Struts tag libraries could be defined

Because Struts application is a genuine Web application, it hasto follow the same rules that any Web application has to follow.And one of them is the presence of web.xml deploymentdescriptor file.

The web.xml file should define ActionServlet, which is thecontroller piece that is provided by the Struts framework, and itsmapping with URI.

As you will see in the example web.xml file in the followingslide, there are several Struts specific initialization parameters.Also the Struts tag libraries also need to be declared.

2/30/2006


11/36

11

11

Example: web.xml1

2

3

4 action

5 org.apache.struts.action.ActionServlet

6

7 config

8 /WEB-INF/struts-config.xml

9

10 ...

11

12

13 action

14 *.do

15

This is the continuation of the web.xml file. Here you see the declarations ofStruts tag libraries.

2/30/2006


12/36

12

12

Step 3: Writestruts-config.xml

The next step is to write struts-config.xml

2/30/2006


13/36

13

13

struts-config.xml? Identify required input forms and then define

them as elements

? Identify required Action's and then define themas elements within element

make sure same value of name attribute of is used as the value ofname attribute of element

define if you want input validation

? Decide view selection logic and specify them as element within element

(read theslide)

2/30/2006


14/36

14

14

struts-config.xml:

1

23 678 9 10 12

This is section of the struts-config.xml file. Here wedefine one element. The value of the name attribute ofthe element is the same as the value of name attribute of element in the following slide.

2/30/2006


15/36

15

15

struts-config.xml:

12 3 45 11 12 13 1415

This is an example of element.

2/30/2006


16/36

16

16

Step 4: WriteActionForm classes

2/30/2006


17/36

17

17

ActionForm Class? Extend org.apache.struts.action.ActionForm

class

? Decide set of properties that reflect the inputform

? Write getter and setter methods for eachproperty

? Write validate() method if input validation is

desired

2/30/2006


18/36

18

18

Write ActionForm class1 package submit;23 import javax.servlet.http.HttpServletRequest;

4 import org.apache.struts.action.*;56 public final class SubmitForm extends ActionForm {78 /* Last Name */9 private String lastName = "Hansen"; // default value10 public String getLastName() {11 return (this.lastName);12 }13 public void setLastName(String lastName) {14 this.lastName = lastName;15 }1617 /* Address */18 private String address = null;19 public String getAddress() {20 return (this.address);21 }22 public void setAddress(String address) {

23 this.address = address;24 }25 ...

2/30/2006


19/36

19

19

Write validate() method1 public final class SubmitForm extends ActionForm {23 ...4 public ActionErrors validate(ActionMapping mapping,5 HttpServletRequest request) {67 ...89 // Check for mandatory data10 ActionErrors errors = new ActionErrors();11 if (lastName == null || lastName.equals("")) {12 errors.add("Last Name", new ActionError("error.lastName"));13 }14 if (address == null || address.equals("")) {15 errors.add("Address", new ActionError("error.address"));16 }17 if (sex == null || sex.equals("")) {18 errors.add("Sex", new ActionError("error.sex"));19 }20 if (age == null || age.equals("")) {21 errors.add("Age", new ActionError("error.age"));

22 }23 return errors;24 }

When this LogonForm is associated with a

controller, it will be passed to the controller

whenever its service is requested by theuser.

JSP pages acting as the view for thisLogonForm are automatically updated by

Struts with the current values of the

UserName and Password properties.If the user changes the properties via the JSP

page, the LogonForm will automatically beupdated by Struts

But what if the user screws up and enters

invalid data? ActionForms providevalidation

Before an ActionForm object is passed to acontroller for processing, a validate

method can be implemented on the formwhich allows the form to belay processing

until the user fixes invalid input as we willsee on the next slide...

2/30/2006


20/36

20

20

Step 5: WriteAction classes

2/30/2006


21/36

21

21

Action Classes? Extend org.apache.struts.action.Action class

? Handle the request

Decide what kind of server-side Model objects(EJB, JDO, etc.) can be invoked

? Based on the outcome, select the next view

2/30/2006


22/36

22

22

Example: Action Class1 package submit;

23 import javax.servlet.http.*;

4 import org.apache.struts.action.*;

5

6 public final class SubmitAction extends Action {

7

8 public ActionForward execute(ActionMapping mapping,

9 ActionForm form,

10 HttpServletRequest request,

11 HttpServletResponse response) {

12

13 SubmitForm f = (SubmitForm) form; // get the form bean

14 // and take the last name value

15 String lastName = f.getLastName();

16 // Translate the name to upper case

17 //and save it in the request object

18 request.setAttribute("lastName", lastName.toUpperCase());

1920 // Forward control to the specified success target

21 return (mapping.findForward("success"));

22 }

23 }

2/30/2006


23/36

23

23

Step 6: CreateApplicationResource.properties

and Configure web.xmlaccordingly

2/30/2006


24/36

24

24

Resource file? Create resource file for default locale

? Create resource files for other locales

2/30/2006


25/36

25

25

Example:ApplicationResource.properties

1 errors.header=Validation Error(s)

2 errors.footer=

3

4 error.lastName=Enter your last name

5 error.address=Enter your address

6 error.sex=Enter your sex

7 error.age=Enter your age

2/30/2006


26/36

26

26

Step 7: Write JSP pages

I

2/30/2006


27/36

27

27

JSP Pages? Write one JSP page for each view

? Use Struts tags for

Handing HTML input forms

Writing out messages

2/30/2006


28/36

28

28

Example: submit.jsp1

2

3

4

56

7 Submit example

8

9

10 Example Submit Page

11

12

13

14

15 Last Name:

16 Address:

17 Sex: Male

18 Female

19 Married:

20 Age:

21 0-19

22 20-4923 50-

24

2/30/2006


29/36

29

29

Example: submit.jsp

1

2 Hello

3

4 young

5 6

7 old

8

9

10

11

12

13

2/30/2006


30/36

30

30

Step 8: Write Ant BuildScript

2/30/2006


31/36

31

31

Write Ant Script? For building and running the application

? If you use NetBeans, this step is not necessary

2/30/2006


32/36

32

32

Step 9: Build, Deploy,and Test Application

2/30/2006


33/36

33

33

Accessing Web Application

2/30/2006


34/36

34

34


2/30/2006


35/36

35

35


2/30/2006


36/36

36

36

Live your lifewith Passion!

2/30/2006

Documents

22-GuideBuidlingStrutsApp36