Installing the Software

Before you begin, you need to install the following software on your computer:

• NetBeans IDE 5.0 (download).
• Java Standard Development Kit (JDK™) version 1.4.2 (download) or 5.0 (download)

Optionally, you can download and use the Sun Java System (SJS) Application Server Platform Edition, JBoss, or WebLogic. However, the Tomcat Web Server that is bundled with the IDE provides all the support you need for two-tier web applications such as the one described in this quick start guide. An application server (such as the SJS Application Server, JBoss, or WebLogic) is only required when you want to develop enterprise applications.

Creating a New Struts Application

In the IDE, a "Struts application" is nothing more than a normal web application accompanied by the Struts libraries and configuration files. You create a Struts application in the same way as you create any other web application in the IDE, with the additional step of indicating that you want the Struts libraries and configuration files to be included in your application.

1. Choose File > New Project. Under Categories, select Web. Under Projects, select Web Application and click Next.

2. In the Name and Location panel, do the following:

   • Under Project Name, enter LoginPage.

   • Change the Project Location to any directory on your computer. From now on, this directory is referred to as $PROJECTHOME.

   • Select the recommendations to which your source structure will adhere, which is purely a personal preference:

     • Java BluePrints. For more information, see http://java.sun.com/blueprints/code/projectconventions.html.

     • Jakarta. For more information, see http://jakarta.apache.org/tomcat/tomcat-5.0-doc/.

   • Select the server to which you want to deploy your application. Only servers that are registered with the IDE are listed. (To register a server, go to Tools > Server Manager.)

   • Notice that the Context Path is /LoginPage.

3. Click Next.

4. In the Frameworks panel, select Struts 1.2.7:

   

   Do not change any of the values in the lower section of this panel. They serve the following purposes:

   • Action Servlet Name. Hardcoded specification of the name of the servlet entry for the Struts action servlet. The web.xml deployment descriptor contains a servlet entry for the action servlet, specifying the appropriate Struts specific parameters, such as the name of the servlet class and the path to the struts-config.xml configuration file.

   • Action URL Pattern. Allows the appropriate patterns which should be mapped to the Struts action controller to be specified. This generates a corresponding web.xml servlet mapping entry to map the specified URI pattern to the action servlet. By default, only the *.do pattern is mapped.

   • Application Resource. Lets you specify the resource bundle which will be used in the struts-config.xml file for localizing messages. By default, this is com.myapp.struts.ApplicationResource.

   • Add Struts TLDs. Lets you generate tag library descriptors for the Struts tag libraries. A tag library descriptor is an XML document which contains additional information about the entire tag library as well as each individual tag. In general, this is not necessary, because you can refer to on-line URIs rather than local TLD files.

5. Click Finish.

The IDE creates the $PROJECTHOME/LoginPage project folder in your filesystem. As with any web application in the IDE, the project folder contains all of your sources and the IDE's project metadata, such as the Ant build script. However, in addition, your web application has all of the Struts libraries on its classpath. Not only are they on the application's classpath, but they are included in the project and will be packaged with it when you build it later in this quick start guide.

The LoginPage project opens in the IDE. You can view its logical structure in the Projects window and its file structure in the Files window. For example, the Projects window should now look as follows:

In the Configuration Files node, the application includes all the Struts-specific configuration files, of which struts-config.xml is the most important. You will use this configuration file throughout this quick start guide. Also in the Configuration Files node, to handle Struts processing, the Struts servlet (i.e., the controller in the MVC paradigm) is mapped in the web.xml deployment descriptor:

<servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <init-param>
        <param-name>config</param-name>
        <param-value>/WEB-INF/struts-config.xml</param-value>
    </init-param>
    <init-param>
        <param-name>debug</param-name>
        <param-value>2</param-value>
    </init-param>
    <init-param>
       <param-name>detail</param-name>
       <param-value>2</param-value>
    </init-param>
    <load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

Above, the Struts servlet (org.apache.struts.action.ActionServlet) is specified as the servlet that will control all requests for the mapping .do. In addition, the web.xml file specifies that the Struts servlet is configured by means of the struts-config.xml file that is found in the WEB-INF folder.

Developing a Struts application is similar to developing any other kind of web application in the IDE. You use components such as JSP pages, servlets, listeners, and filters. However, you complement your web development toolkit by using the facilities provided by Struts via the IDE. For example, you use templates in the IDE to create Struts action classes and Struts actionform bean classes. On top of that, the IDE automatically registers these classes in the struts-config.xml file and lets you extend this file very easily via menu items in the Source Editor's pop-up menu.

Using Struts Custom Tag Libraries in a JSP Page

Many web applications use JavaServer Pages (JSP) for the view in the MVC paradigm, so Struts provides custom tag libraries which facilitate interaction with HTML forms. These can very easily and smoothly be set up and used in a JSP page in the IDE.

1. Right-click the LoginPage project node, choose New > JSP, and call the new JSP page loginForm. Click Finish.

2. In the Source Editor, change the default content of the <H1> tag to Login Form and do the same for the text in the <TITLE> tags.

3. Copy these first two taglib directives from the welcomeStruts.jsp file to the top of your new loginForm.jsp file:

   <%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean" %>
   <%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html" %>
   

4. In loginForm.jsp, below the <H1> tags, add the following:

   <html:form action="login">
   
      <html:submit value="Login" />
   
   </html:form>

   Notice that when you type the Struts tags, the IDE helps you by suggesting different ways of completing the code that you're typing, and further helps you by providing Struts Javadoc:

   

   Whenever you finish typing in the Source Editor, you can neaten the code by right-clicking in the Source Editor and choosing Reformat Code:

   

5. In the Component Palette on the right side of the Source Editor, within the HTML section, drag the Table item to just above the <html:submit value="Login" /> line. The Insert Table dialog box pops up. Set both the Rows and Columns to 1, so that you'll create a table consisting of one row and one column. Click OK.

   The loginForm.jsp now looks as follows:

   <html:form action="login">
       <table border="1">
           <thead>
               <tr>
                   <th></th>
               </tr>
           </thead>
           <tbody>
               <tr>
                   <td></td>
               </tr>
           </tbody>
       </table>
   
       <html:submit value="Login" />
   
   </html:form>

6. In between the <TH> tags, type the following:

   <bean:message key="login.name" />

   In between the <TD> tags, type the following:

   <html:text property="name" />

   The body of loginForm.jsp is now as follows:

   

7. In the Projects window, expand the Source Packages node, expand the com.myapp.struts node, and double-click the ApplicationResource.properties file so that it opens in the Source Editor. Add login.name as a key, anywhere in the ApplicationResource.properties file, and add a meaningful message. For example:

   login.name=Name

Using Struts to Validate a Field in a JSP Page

A Struts "actionform bean" class represents data shared between the view (in this case, a JSP page) and the Struts action class. An actionform bean class is available both for populating the view and for providing input to an action class. An actioform bean class also has a validate method to allow input mapped from the view to be verified.

1. Right-click the LoginPage project node and choose New > File/Folder. In the Web category choose Struts ActionForm Bean and click Next. Notice that your actionform bean class will be called "NewStrutsActionForm". Leave the default name for purposes of this tutorial. In a real application, you would give your actionform bean class a new, meaningful name. Select com.myapp.struts in the Package drop-down list and click Finish.

   The actionform bean class opens in the Source Editor. By default, the IDE provides it with a String called name and an int called number. Both fields also have getters and setters defined for them.

2. Open struts-config.xml in the Source Editor and note that it contains, among other things, the following:

   <form-beans>
       <form-bean name="NewStrutsActionForm" type="com.myapp.struts.NewStrutsActionForm"/>
   </form-beans>

   Hold down the Ctrl key and move your mouse over the actionform bean class's fully qualified class name:

   

   A hyperlink appears. Click it to navigate to the actionform bean class.

3. Now browse through the actionform bean class in the Source Editor. Look at the validate method that the IDE created for you:

      public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
           ActionErrors errors = new ActionErrors();
           if (getName() == null || getName().length() < 1) {
               errors.add("name", new ActionMessage("error.name.required"));
               // TODO: add 'error.name.required' key to your resources
           }
           return errors;
       }

   Notice that the field called name is validated by default. If validation fails, which happens when no name is entered in the JSP page, a message that is identified by error.name.required is returned.

4. Following the TODO instruction that the IDE put in the validate method for you, add error.name.required as a key to the ApplicationResource.properties file and add a meaningful message. For example:

   error.name.required=Enter a name!

   At the top of the file, to customize the formatting of your error message, change the first four keys to the following:

   errors.header=
   errors.prefix=<span style="color: red">
   errors.suffix=</span>
   errors.footer=
   

5. Specify where you want the error message to be rendered, by adding the following line in loginForm.jsp, right above the closing </html:form> tag:

   <html:errors />

Using Struts to Navigate between JSP Pages

A Struts "action" class is executed in response to a user request and commonly interacts with the model through a business delegate. The responsibility of an action class is to provide navigation and forward control to the appropriate view.

1. Right-click the LoginPage project node and choose New > File/Folder. In the Web category choose Struts Action and click Next.

2. In the Name and Location panel, notice that your action class will be called "NewStrutsAction". Leave the default name for purposes of this tutorial. In a real application, you would give your action class a new, meaningful name.

3. Select com.myapp.struts in the Package drop-down list.

4. Type login in Action Path (the content of Action Path is therefore now /login). Click Next.

5. In ActionForm Bean, Parameter, notice that the IDE suggests that you associate the action class with the actionform bean class that you created in the previous step. In Input Resource, browse to your loginForm.jsp page. Click Finish.

6. Open struts-config.xml in the Source Editor and note that it contains, among other things, the following:

   <action-mappings>
      <action input="/loginForm.jsp"
               name="NewStrutsActionForm"
               path="/login"
              scope="session"
               type="com.myapp.struts.NewStrutsAction"/>
      <action path="/Welcome"
           forward="/welcomeStruts.jsp"/>
   </action-mappings>

   If you want the action class to function per request, instead of per session, put the cursor in the scope attribute and press Ctrl-Space:

   

   Choose Request.

7. Hold down the Ctrl key and move your mouse over the action class's fully qualified class name:

   

   A hyperlink appears. Click it to navigate to the action class.

8. Browse through the action class and look at the execute method:

   public ActionForward execute(ActionMapping mapping, ActionForm  form,
               HttpServletRequest request, HttpServletResponse response)
               throws Exception {
   
           return mapping.findForward(SUCCESS);
   
   }

   Notice the definition of SUCCESS, at the top of the NewStrutsAction:

   private final static String SUCCESS = "success";

   The SUCCESS String declaration specifies that this action class forwards to the output view called success.

9. You need to define a page that will be displayed when the output view above is called. So, create another JSP in the same location as loginForm.jsp and call it loginSuccessful. In the Source Editor, change the default content of the <H1> tags in the new JSP files to Login Successful! and do the same for the text in the <TITLE> tags.

10. Open struts-config.xml in the Source Editor, right-click anywhere in the /login action mapping, and choose Struts > Add Forward:

    

    The Add Forward dialog box opens.

    Type success in Forward Name. Browse to loginSuccessful.jsp in Resource File. The dialog box should now look as follows:

    

    Click Add.

    Notice that struts-config.xml now shows the following (the new code is in bold):

    <action-mappings>
    
      <action input="/loginForm.jsp"
               name="NewStrutsActionForm"
               path="/login"
              scope="session"
               type="com.myapp.struts.NewStrutsAction">
           <forward name="success"
                    path="/loginSuccessful.jsp"/>
      </action>
    
      <action path="/Welcome"
           forward="/welcomeStruts.jsp"/>
    
    </action-mappings>

Using Struts to Add "Cancel" Functionality

1. In loginForm.jsp, below the <html:submit> line, create the Cancel button by adding the following:

   <html:cancel />

2. Add these lines to the execute method in org.myapp.struts.NewStrutsAction:

   if (isCancelled(request)){
     return mapping.findForward(CANCEL);
   }

   Press Ctrl-Space within the isCancelled method and then read the Javadoc to understand the method:

   

   Declare the definition of CANCEL at the top of the NewStrutsAction class, right below the definition of SUCCESS:

   private final static String CANCEL = "cancel";

3. You need to define a page that will be displayed when CANCEL is called. So, create another JSP in the same location as loginForm.jsp and call it loginCancel. In the Source Editor, change the default content of the <H1> tags in the new JSP files to Login Cancelled! and do the same for the text in the <TITLE> tags.

4. Open struts-config.xml in the Source Editor, right-click anywhere in the /login action mapping, and choose Struts > Add Forward. The Add Forward dialog box opens.

   Type cancel in Forward Name. Browse to loginCancel.jsp in Resource File. The dialog box should now look as follows:

   

   Click Add.

   Notice that struts-config.xml now shows the following (the new code is in bold):

   <action-mappings>
   
     <action input="/loginForm.jsp"
              name="NewStrutsActionForm"
              path="/login"
             scope="session"
              type="com.myapp.struts.NewStrutsAction">
          <forward name="success"
   		path="/loginSuccessful.jsp"/>
          <forward name="cancel"
                   path="/loginCancel.jsp"/>
     </action>
   
     <action path="/Welcome"
          forward="/welcomeStruts.jsp"/>
   
   </action-mappings>

5. Run the application again and notice the new Cancel button:

   

   Click it and notice that the new loginCancel.jsp page is opened in the browser.

Using Struts to Add "Logout" Functionality

1. In loginForm.jsp, below the <H1> tags, create the Logout link by adding the following:

   <html:link action="/logout">Logout</html:link>

2. You need to define a page that will be displayed when the Logout link is clicked. So, create another JSP in the same location as loginForm.jsp and call it loginOut. In the Source Editor, change the default content of the <H1> tags in the new JSP files to Have a Nice Day! and do the same for the text in the <TITLE> tags.

3. Open struts-config.xml in the Source Editor, right-click anywhere, and choose Struts > Add Forward/Include Action. The Add Forward/Include Action dialog box opens.

   Type logout in Action Path. Browse to loginOut.jsp in Resource File. The dialog box should now look as follows:

   

   Click Add.

   Notice that struts-config.xml now shows the following (the new code is in bold):

   <action-mappings>
   
     <action input="/loginForm.jsp"
              name="NewStrutsActionForm"
              path="/login"
             scope="session"
              type="com.myapp.struts.NewStrutsAction">
          <forward name="success"
   		path="/loginSuccessful.jsp"/>
          <forward name="cancel"
                   path="/loginCancel.jsp"/>
     </action>
   
     <action forward="/loginOut.jsp"
          path="/logout"/>
   
     <action path="/Welcome"
          forward="/welcomeStruts.jsp"/>
   
   </action-mappings>

4. Run the application again and notice the new Logout link:

   

   Click it and notice that the new loginOut.jsp page is opened in the browser.

Using Struts to Add "Reset" Functionality

1. In loginForm.jsp, between the Submit and Cancel buttons, create the Reset button by adding the following:

   <html:reset />

2. Run the application again and notice the new Reset button:

   

   Type something in the Name row, click Reset, and notice that Struts empties the table.