Difference between revisions of "Java-Business-Application/C2/Java-servlets-and-JSPs/English-timed"
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Revision as of 14:41, 24 June 2014
| Time | Narration |
| 00.01 | Welcome to the spoken-tutorial on Java Servlets and JSPs. |
| 00.06 | In this tutorial we will learn about: |
| 00.09 | 'Web server |
| 00.10 | Web container |
| 00.12 | We will also learn to create a simple Java Servlet and JSP |
| 00.18 | Here we are using |
| 00.20 | Ubuntu Version 12.04 |
| 00.23 | Netbeans IDE 7.3 |
| 00.27 | JDK 1.7 |
| 00.29 | Firefox web-browser 21.0 |
| 00.33 | You can use any web-browser of your choice. |
| 00.37 | To follow this tutorial you must have knowledge of |
| 00.41 | Core Java using Netbeans IDE and |
| 00.45 | HTML |
| 00.47 | If not, for relevant tutorials please visit our website. |
| 00.52 | Before moving onto Servlets and JSP, let us first understand a web server. |
| 00.58 | A web server is a system that delivers content to end-users over the Internet. |
| 01.05 | It is also known as Internet server. |
| 01.10 | A web container is a component of the web server that interacts with Java servlets |
| 01.18 | It is also known as servlet container. |
| 01.22 | The servlet container allows the servlets to execute inside it. |
| 01.28 | Now, let us learn how to write a simple servlet. |
| 01.32 | Switch to the Netbeans IDE.
|
| 01.35 | Click on the Projects tab on the left hand side of the IDE. |
| 01.40 | Earlier we had created a simple Project named MyFirstProject. |
| 01.46 | You can see it here on the left hand side of the IDE. |
| 01.50 | Let us now create a simple servlet inside this project. |
| 01.55 | So, right-click on MyFirstProject.
|
| 01.59 | Go to New and click on Servlets. |
| 02.03 | A New Servlet window opens. |
| 02.05 | Type the Class Name as MyServlet. |
| 02.09 | Type the Package Name as org.spokentutorial |
| 02.16 | Then click on Next. |
| 02.18 | Click on Add information to deployment descriptor (web.xml). |
| 02.23 | We can see that the Class Name is org.spokentutorial.MyServlet. |
| 02.30 | We can see that Servlet Name is same as that of the Class Name which is MyServlet. |
| 02.37 | Note that the URL pattern is the same name as that of the Class Name. i.e MyServlet |
| 02.45 | We can change it to MyServletPath. |
| 02.50 | Then click on Finish. |
| 02.53 | The source code created by the IDE for MyServlet.java is seen in the Source Editor Window. |
| 03.01 | We see MyServlet.java is created in the package org.spokentutorial. |
| 03.09 | Notice that a servlet is just like any other Java class. |
| 03.14 | Except that a servlet does not have a main method. |
| 03.19 | Now, let us learn something about Glassfish server. |
| 03.24 | A servlet is deployed in a servlet container. |
| 03.28 | We are using Glassfish as our server. |
| 03.32 | Servlet container is a component of Glassfish that interacts with servlets. |
| 03.39 | Now, let us come back to Netbeans IDE. |
| 03.42 | Note that MyServlet extends the HttpServlet. |
| 03.48 | At the bottom of the code, we can see HttpServlet methods. |
| 03.54 | Click on the plus sign on the left, to view these methods. |
| 03.59 | We see the methods - doGet, doPost and getServletInfo methods. |
| 04.09 | We can override these methods. |
| 04.12 | We can see that there is one more method named processRequest at the top. |
| 04.18 | We will delete processRequest and getServletInfo methods to avoid confusion. |
| 04.25 | So we are left with two methods doGet and doPost. |
| 04.31 | For now, we will look at the doGet method. |
| 04.35 | doGet is the default method for any simple URL request. |
| 04.41 | So we will type some code inside the doGet method. |
| 04.45 | We had already deleted processRequest method. |
| 04.49 | So, remove the method call for processRequest method. |
| 04.54 | Also remove it from the doPost method. |
| 04.58 | Now, let us come to the doGet method |
| 05.01 | We can see that there are two parameters that are passed to the doGet method. |
| 05.07 | One is the request and the other is the response object. |
| 05.12 | Also notice that, request is of type HttpServletRequest. |
| 05.18 | And response object is of type HttpServletResponse. |
| 05.22 | We will use the response object to send the HTML response back to the client side. |
| 05.30 | For that, we will have to create a PrintWriter object. |
| 05.35 | Notice that the PrintWriter class is already imported. |
| 05.40 | So, inside the doGet method type PrintWriter space writer equal to response dot getWriter open and close brackets semicolon |
| 05.57 | Press Enter. |
| 05.59 | On the next line type - |
| 06.02 | writer dot println within brackets and double quotes welcome. |
| 06.09 | Then, Press Ctrl S to save the file. |
| 06.14 | Now, let us run the servlet. |
| 06.17 | So on the left hand side, in the Projects tab right click on MyServlet dot java. |
| 06.24 | Then, Click on Run File. |
| 06.27 | We get a Set Servlet Execution URI dialog box. |
| 06.32 | Click on OK. |
| 06.35 | When the browser window opens, look at the URL. |
| 06.39 | It is localhost colon 8080 slash MyFirstProject slash MyServletPath. |
| 06.47 | Here MyFirstProject is the context name and MyServletPath is the URL Pattern that we had set. |
| 06.55 | We see the text welcome printed on the browser. |
| 07.00 | Now go back to the netbeans IDE. |
| 07.03 | In the println method we can pass html code. |
| 07.07 | For example, put welcome in h3 tag. |
| 07.12 | Now,Save the file. |
| 07.14 | Since we deployed this servlet earlier, we need not run it again.
|
| 07.20 | The web container automatically detects it. |
| 07.23 | So, we can go back to the browser. |
| 07.27 | Refresh.
|
| 07.28 | We see the message Welcome in a different format. |
| 07.32 | Now, come back to the IDE. |
| 07.35 | Thus, we have successfully created a servlet. |
| 07.39 | We can create any web application using servlets. |
| 07.45 | We used the servlet to display an HTML code. |
| 07.49 | Notice that, we have HTML code inside the Java code. |
| 07.54 | Even though this is possible, it is difficult to do for large web applications. |
| 08.00 | And hence not a recommended practice. |
| 08.03 | It would be better to replace this using JSP (Java Server Pages.) |
| 08.10 | We will see the use of servlets and jsps. |
| 08.13 | Servlets and JSPs are used together to separate presentation from content. |
| 08.20 | Servlets act as the controller and JSPs act as the view |
| 08.25 | Servlets contain HTML code inside Java code. |
| 08.30 | JSPs contain Java code inside HTML code. |
| 08.35 | We will learn more about these in the coming tutorials. |
| 08.39 | Now, Switch back to Netbeans IDE. |
| 08.42 | We will now create a simple JSP page. |
| 08.47 | So, Right click on MyFirstProject. |
| 08.50 | Go to New. |
| 08.51 | and click on JSP. |
| 08.54 | A new JSP window opens. |
| 08.57 | Type the filename as welcome . |
| 09.01 | And then click on Finish. |
| 09.04 | Click on the Projects tab on the left hand side |
| 09.07 | We can see that Welcome.jsp is under Web Pages folder. |
| 09.13 | Now, In the editor, change Hello World to Welcome. |
| 09.19 | Notice that Welcome is within h1 tags. |
| 09.23 | Now, Save the file. |
| 09.25 | Come back to the browser. |
| 09.27 | In the url after MyFirstProject slash type welcome.jsp |
| 09.35 | We see the output Welcome. |
| 09.38 | Therefore for presentation purpose jsp is preferred. |
| 09.42 | Let us summarize |
| 09.44 | In this tutorial we have learnt |
| 09.47 | About web server and web container |
| 09.49 | To create a simple servlet |
| 09.52 | To create a simple jsp |
| 09.55 | Please make sure that you have completed this tutorial before proceeding further. |
| 10.01 | Watch the video available at the following link |
| 10.04 | It summarizes the Spoken Tutorial project |
| 10.08 | If you do not have good bandwidth, you can download and watch it |
| 10.13 | The Spoken Tutorial Project Team |
| 10.15 | Conducts workshops using spoken tutorials |
| 10.19 | Gives certificates for those who pass an online test |
| 10.22 | For more details, please write to contact at spoken hyphen tutorial dot org |
| 10.28 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 10.32 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 10.40 | More information on this Mission is available at http://spoken-tutorial.org/NMEICT- Intro |
| 10.50 | The Library Management System has been contributed by a leading software MNC, through their Corporate Social Responsibility program |
| 11.00 | They have also validated the content for this spoken tutorial. |
| 11.04 | This is Arya Ratish from IIT Bombay signing off.
Thank you for joining. |
