Category: CSE Seminar Topics

Netbeans  Introduction:-

•  Type: IDE software for java environment.
•  Vendor: sun Microsystems (oracle corp).
• Open source software.
• To download from www.netbeans.org gives glassfish as built-in server also allows configuring other extend servers.
• To get help: www.netbeans.org version: 6.7.1 (compatable with jdk1.5/1.6).
• Netbeans IDE is good for web application.

 

Database table of Struts application:-

SQL> create table user-list (username varchar (20), password varchar (20))

       >insert into user-list values (‘ramu’, ‘jalli’);

      > insert into user-list values (‘ramu’, ‘pass’);

Query of the Struts application:- 

Select count (*) from user-list where username = “ramu” and password = “jalli”;

Count (*) ->1 (Valid credentials)  (or)   count (*) -> 0 (invalid credentials)

Procedure to develop in the above diagram Struts application by using NetBeans IED:-

Step1:- create java web project in Net Beans IDE by adding Struts capabilities to it.

              File –> new project –>java web –>web applicatio –>Next –>

                       Project name: StrutsDemoApp2 –>Next  –>Next –>

                               Select Struts 1.3.8

                                 Select ass Struts tld  –>finish –> Delete endex.jsp, Welcome Struts.jsp files.

Step2: Add ojdbc 14.jar file to the libraries of the project.

                Right click on libraries –>add jar –>ojdbc14.jar file browser & select.

Note:-  Jar files added to the my computer class path environment variable is not visible & access with projects created in IDE s/w. so add them to the libraries of IDE project separately.

Step3: Add form bean class to project (RegisterForm)

            Right click on source packages folder –>new  –>Struts Actionform bean

                               Classname: RegisterForm

                               Package: app.ram –> finish –>delete existing code of RegisterForm class

                                     –> declare private string username, password; –>select this line & right click –>

                                    –>insert code(Alt+insert) –>getter & setter methods.

Step4: add Action class to Struts application (project)(RegisterAction)

             Rightclick on source package  –>new –>Struts Action

                                  Classname: RegisterAction

                                    Package: app

                                  Action path: /register –>next

                                  ActionFormbean name: RegisterForm

                                  Scope:  .session O request  –> finish.

Step5: add action forward configuration to RegisterAction class configuration pointing to register.jsp.

In Struts-config.xml

                     <action name = “RegisterForm” path = “/register” scope = ”session” type = “app.

                                                                                                RegisterAction”>

                               <forward name = “result” path =”/register.jsp” />

                                  </action>

Step6: add register.jsp to the profect

          Right click on web pages –>new  –> jsp

                             Filename: register –> finish.

Register.jsp

   <% @ taglib uri = “/WEB-INF/Struts-html.ltd” prefix = “j” %>

   <% @ taglib uri = “/WEB-INF/Struts-bean.ltd” prefix = “bean” %>

   <% @ taglib uri = “/WEB-INF/Struts-logic.ltd” prefix = “logic” %>

      <j: form action = “register”>

                Username: <j: text properties = “username”/><br>

                Username: <j: password properties = “password”/><br>

                    <j: submit value = “checkDetails”/>

                     <j: form>

                        <br><br>

                      Result is: <logic: notEmpty name = “msg”>

                                       <bean: write name = “msg”>

                                        </logic: notEmpty>

Write the following code in the execute () of RegisterAction class:-

    Public ActionForward execute (-,-,-,-) throws exception

           {

              //type casting

  RegisterForm fm = (RegisterForm) fm;

         //read form page form data from form bean class object

                 String user = fm.getusername ();

                 String pwd = fm.getpassword ();

                        // write jdbc code

                             //create jdbc con object

                              Class.forname (“oracle.jdbc.driver.oracleDriver”);

                        Connection con = DriverMananger.get connection (“jdbc: oracle: thin: @localhost: 1521:

                                                                                             orcl”, “scott”, “tiger”);

             // [ctrl+shift+I – gives import statement dynamically]

              //create jdbc statement object

                 // preparedstatement ps = con. Preparestatement (“select count (*) from user-list where

                                                                               Username =? and password =?”);

                 // set values to programs.

                   Ps.setString (1, user);

                  Ps.setString (2, pwd);

                  // send & execute SQL query in D>B> s/w

             ResultSet rs = ps.execute Query ();

              // process the result

                    Int cnt = 0;

                        If (rs.next ())

                              Cnt = rs.getint (1);

                   If (cnt == 1)

                      Request.setAttribute (“msg”, “valid credentials”);

                        Else

                           Request.setAttribute (“msg”, “ivalid credentials”);

             Return mapping.findForward (“result1”);

      }

}

Step7: Run the project.

        right click on project  –>Run

• Most of the IDE software’s redeploy’s the project (web application) once modification are done in the source in the source code of the project.
• In order to make ActionServlet as front controller we need to configure the ActionServlet class in web.xml file either with extension match url-pattern or Directory match url-pattern.

Procedure to make first Struts application working with directory match url-pattern based ActionServlet class. (with respect to 1^st app.)

Step1: configure ActionServlet in web.xml file having directory match url-pattern

     In web.xml

          <servlet-mapping>

               <servlet-name> action </ servlet-name>

                <u-p> /x/y/* </u-p>

            </servlet-mapping>

Step2: configure the target action class of form page by having the following action path.

    In Struts-config.xml

            <action path = “/x/y/register” type = “app.RegisterAction” name = “rf”>

                 <forward name = “result” path = “/register.jsp”/>

             </action>

Step3: design form page Action url as shown below

            <% @ taglib uri ———-

                        —————-

               <html: form action = “/x/y/register”>

                     Username: < ——

                      Password: < ———–

                                 <html: submit  

                     </html: from>

Step4: develop remaining resource of application like other regular struts applications.

Conclusion:-

It is always to recommended to configure ActionServlet with Extension match url pattern.

To make ActionServlet trapping form page request and to make Action Servlet passing that request to starts Action class the Action url of form page (action attribute value of form tag) should be designed as shown below.

<action path of target Action class>.<extension mode in the url pattern of ActionServlet> 

Example: – if ActionServlet url pattern is *.abc

         If target Action class action path is /xyz then the form page Action url should be “xyz.abc”

Register.html (Form page) (View Layer):

<form action =”reg.do” method =”get”>                                                 —–>3 and reg.do—–>5

Username: <input type =”text” name=”uname”><br>

Password: <input type=”password” name=”password”><br>

<input type =”submit” value =”send”>                                                                 –> 4

</form>

In reg.do

Reg is actionpath of registeraction class”, .do is extension word in the url-pattern of action servlet.

Action Servlet (Controller Servlet)

Server Reads Web.xml/Container                       —->1,2

*.do —> 10

Resultpage.jsp (View Layer)                                —-> 19

Result.jsp

……..

……..

Presentation logic (Response going browser window)          —> 20

RegisterForm.java: (formbeanclass) (controller Layer)

Package app:

Public class Registerform extends action form

{

Private string uname;

Private string password;

Public void set xxx()

{

…..               —-> 14

}

Public void get xxx ()

{

……

}

}

Web-xml (D.D File)

<Web-app>

<servlet>

<s-n>action</s-n>          –> 8

<s-c>org.apache.structs.action.actionservlet</s-c>        —>9

<init-param>

<p-n>config</p-n>

<p-v>|WEB-INF|Structs-config.xml</p-v>

</init-param>

<1-0-s>2</1-0-s>

</servlet>

<servlet-mapping>

<s-n>action</s-n>         –> 7

<u-p>*.do</u-p>

</servlet-mapping>

</web-app>

Struts-config.xml (Strts configuration file and controller layer)

<struts-config>

<form-beans>

<form-bean name=”rf” type=”app.registerform”>         –>13

</form-beans>

<action-mappings>

<action-path =:/reg” type=”app registration” name =”rf”>            —-> reg-11, registeraction-15, rf-12

<forward name=”Success” path=”/result.jsp”/>                               —>18

</action-mappings>

</struts-config> 

RegisterAction (StrutsAction Calss) (Model Layer) 

Package app;

Public class register action extends action

{

Public action forward execute (—-)

{

………………                      –>16

Return actionforward obj (logical success names);            —>17

}

With respect to above sample code:-

1) Programmer deploys struts application in web server / application server.

2)  Based on load-on-startup the servlet container creates ActionServlet class object either during server startup or during the deployment of struts application. In this process ActionServlet reads & verifies the struts-configuration file entries.

3) End user launches the form page (register.html) on browser window.

4)  And 5) After filling up the form end user submits the form page which generates request url “reg.do” (http request)

6), 7), 8), 9) Since Actionservlet url pattern is *.do and form page generated request url having reg.do the ActionServlet traps & takes the request

10) ActionServlet reads form data from the form page

11) Based on “reg” word of request url the ActionServlet searches for an Action class configuration in struts configuration file whose action path is “/reg”

12) The name “rf” attribute of Action tag will be used by ActionServlet to know the form bean i.e linked with struts.Action class

13) ActionServlet creates/locates the register form class object

14) ActionServlet calls set xxx () methods on FormBean class object to write form date to FormBean properties.

15) ActionServlet creates / locates struts Action class object (Register Action)

16) ActionServlet calls execute() method of struts Action class to process the request by executing business logic

17) This execute () method returns ActionForward object with the logical name “success” to ActionServlet.

18) ActionServlet uses ActionForward configuration and got result.jsp as the result page.

19) ActionServlet forwards the control to the result page “result.jsp”.

20) The presentation logic of result.jsp formats the result and sends the results to browser window as response in the form of web page.