Java Servlets Tutorial
Java Servlet Technology resides at server side and it generates the dynamic web page, used to create a web application. Java Servlets Tutorial are programs that act as a middle layer between a request coming from a Web browser/HTTP client and databases or the applications on the HTTP server.
Java Servlet can be defined in many ways, which depends on the context.
– A servlet is one of the technologies which is used to create the web application.
– A servlet is an API which provides many interfaces and classes including documentation.
– The servlet is an interface, which must be implemented for creating any servlet.
– The servlet is a class that extends the capabilities of the servers and responds to the incoming request.
– A servlet can respond to any type of requests.
– Servlet is a web component which is disposed on the server to create a dynamic web page.
– A servlet is called as an object. It receives a request and generates a response which is based on a request.
There are some important key points that must be known while programming of a servlet, such as a server, container, get and post request etc. The basic terms used in servlet areas:
• HTTP(Hypertext Transfer Protocol)
• HTTP Request Types
• Differences between getting and post method
• Server and distinction between web and application server
• Content Type
• XML introduction
Also, Java servlets can be generated automatically from JSP that is Java Server Pages by the JSP compiler. There are differences between Java servlets and JSP that is servlets typically enclosed HTML inside Java code, while JSP enclosed Java code in HTML.
To deploy and run the servlet, a Java servlet container (web container) must be used. The servlet container is actually the component of a web server which interacts with the servlets. The servlet/web container is responsible for managing the lifecycle of servlets, also mapping a URL to a particular servlet and assuring that the URL requester has the correct access rights.
Life Cycle of Java Servlets Tutorial:-
A Java servlet life cycle can be described as the entire process from its creation till the destruction. Following are the paths followed by a Java servlet:
– The Java servlet is initialized by calling the init () method.
– The init() method can be called at only once. Firstly, it is called when a servlet is created and not called again for each user request.
– Simply, the init() method creates(loads) some data that will be used throughout the life of the servlet.
– The servlet calls service() method to process a client’s request.
– The actual task is performed by the service() method. It is one of the main methods.
– The web(servlet) container calls the service() method which is used to handle requests coming from the browsers.
– The service() method is called by the container which invokes doGet, doPost, doPut, doDelete.
– In each service request, doGet() and doPost() methods are frequently used.
– The servlet is terminated by calling the destroy() method.
– This method is also called at only once at the end of the servlet’s lifecycle.
– The destroy() method gives a chance to a servlet to close the database connections.
4) Finally, a Java servlet is garbage collected by the garbage collector of the JVM.
Why is a training of Java Servlets required?
A Java servlet gives a platform-independent, component-based method for building Web-based applications without the performance limitations of CGI programs. Java Servlets have access to the JDBC API to access enterprise databases, including the entire family of Java APIs.
There are some uses that are why Java servlets tutorial are used which are as follows:
– Servlets are often used to process or store the data that was submitted from an HTML form.
– Servlets also used to give dynamic content such as the results of a database query.
– Servlets manage state information which does not exist in the stateless HTTP protocol.
– You can collect input from users through web page forms by using a servlet.
– By using Java servlets, you can create dynamic web pages and also present records from the database or another source.
– Also, Java Servlets often provide the same purpose as programs implemented using the CGI(Common Gateway Interface).
There are also some major tasks of Java servlets tutorial that are as follows:
– Servlet reads the explicit data sent by the browsers(clients). This contains an HTML form on a Web page or it could also come from an applet.
– It reads the implicit HTTP request data sent by the browsers(clients). This consist of cookies, media types and compression schemes the browser understands, and so forth.
– Servlets process the data and generate the results. This process requires talking to a database, executing an RMI or CORBA call, invoking a Web service, or computing the response directly.
– It sends the explicit data that is the document to the clients. This document can be sent in different formats, including text (HTML or XML), binary (GIF images), Excel, etc.
– It also sends the implicit HTTP response to the browsers or clients. This includes telling the browsers and other clients what type of document is being returned (e.g., HTML), setting cookies and caching parameters, and other similar tasks.
Goals and Objectives of Java Servlets Tutorial Course:
- The primary goal of this course is to prepare students for a successful professional career in the advance java.
- To get a good knowledge of java servlets.
- Who works in other technology but interested to learn Java Servlets, for them online learning platform is best because it saves time and other efforts.
- The main purpose of Java Servlets is that they grant browsers to upload intelligent search agents to a Web server.
- Java Servlets handle the communications protocols required to send applets to a web browser.
- In simple words, the main objective is to make you awesome in java servlets.
Java Servlets Tutorial Course Pre-Requisites:
- Basic Computer Knowledge
- Passion to Learn
- Knowledge about C, C#
Target Audience for Java Servlets Tutorial Course
- Java Professionals or developers
- New developers who are interested to learn Java Servlets.
- New as well as experienced users also, of all Java language.
- All developers
- This Java servlets tutorial course is designed who want to make their future in java.
- This Java servlets tutorial has been prepared for the beginners to help them to understand the basic to advanced concepts of Java Servlets.
- This learning program will give you enough understanding on Java servlet concepts from where you can take yourself means from beginners to a higher level of expertise.
Java Servlets Tutorial Courses Advantages:
CGI technology has some disadvantages which were overcome by Java servlet. Various advantages of Java servlets Tutorial are as follows:
• Servlet container creates threads for handling multiple requests to the servlet. Threads have lots of advantages over the Processes.
• Servlet gives better performance because it creates a thread for each request.
• There is no any Portability issue because it uses Java language.
• No need to worry about the memory leak, garbage collection etc because Java servlets are managed by the JVM.
• Java servlets tutorial is secure because it uses Java language.
• Servlets are written in Java so they are platform independent.
• There is no need to create a separate process to handle each client request because they execute within the address space of web server.
• Java servlets tutorial can communicate with databases, applets or other software via the sockets and RMI because full functionality of the Java class libraries is available to the servlet.
• It doesn’t require installing a particular piece of software to access/manipulating java applications.
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