Servlets

A session is a collection of HTTP requests, over a period of time, between a client and server. Maintaining the data within the session is known as session tracking. For example, maintaining the book details added to the cart in an online book shop application. Session tracking mechanisms include the following: URL rewriting (query strings) […]

In a web application it is common to redirect the user to a web page. For example on successful authentication of a user, he/she is redirected to user home page. Otherwise, redirected to login page again. We have to ways to redirect a user: one is using the sendRedirect() method available on response object and […]

It is common in web applications to pass data or parameters from one to another page. To retrieve the values of various elements in a HTML form or from another page, we can use the following methods which are available in HttpServletRequest object: String getParameter(String  name) Enumeration getParameterNames() String[] getParamterValues(String  name)   Following example demonstrates […]

Most of the time, data (Ex: admin email, database username and password, user roles etc…) need to be provided in the production mode (client choice). Initialization parameters can reduce the complexity and maintenance. Initialization parameters are specified in the web.xml file as follows: <servlet> <servlet-name>Name of servlet</servlet-name> <servlet-class>Servlet class</servlet-class> <init-param> <param-name>Mail</param-name> <param-value>[email protected]</param-value> </init-param> </servlet>   […]

Here we will learn how to create and execute a servlet manually i.e., without using any IDEs. For developing web applications using servlets you need a application server like Apache Tomcat, and a text editor like notepad.   Video: Apache Tomcat Installation   A servlet is a normal java class which follows these set of rules: […]

Servlet API is a set of classes and interfaces that specify a contract between a servlet class and a servlet container. Some examples of servers that provide servlet containers are: Apache Tomcat, Oracle’s WebLogic, IBM’s Websphere, JBoss etc. All the API classes and interfaces are grouped into following packages: javax.servlet javax.servlet.http   javax.servlet Package   […]

Introduction   Life cycle of a servlet contains the following stages: Instantiation Initialization Servicing Destruction   Following figure illustrates the life cycle of a servlet:     Instantiation   In this stage the servlet container searches the web.xml file for servlet. If the servlet is found, it will create an object for the corresponding servlet […]

Servlets is a Java based technology for server side processing. Other languages or technologies for server side processing are PHP, JSP, node.js, Perl etc.   Definition of a Servlet   A servlet is a special Java class which is dynamically loaded on the server and used to generate dynamic content.   Following are the general […]