Servlet Packages
There are two packages in Java Servlet that provide various features to servlet. These two packages are javax.servlet and javax.servlet.http.
javax.servlet package: This package contains various servlet interfaces and classes which are capable of handling any type of protocol.
javax.servlet.http package: This package contains various interfaces and classes which are capable of handling a specific http type of protocol.
Overview of some important interfaces and classes
javax.servlet package interface
Some of the important interfaces are listed below.
Interface |
Overview |
Servlet |
This interface is used to create a servlet class. Each servlet class must require to implement this interface either directly or indirectly. |
ServletRequest |
The object of this interface is used to retrieve the information from the user. |
ServletResponse |
The object of this interface is used to provide response to the user. |
ServletConfig |
ServletConfig object is used to provide the information to the servlet class explicitly. |
ServletContext |
The object of ServletContext is used to provide the information to the web application explicitly. |
javax.servlet package classes
Some of the important classes are listed below.
Classes |
Overview |
GenericServlet |
This is used to create servlet class. Internally, it implements the Servlet interface. |
ServletInputStream |
This class is used to read the binary data from user requests. |
ServletOutputStream |
This class is used to send binary data to the user side. |
ServletException |
This class is used to handle the exceptions occur in servlets. |
ServletContextEvent |
If any changes are made in servlet context of web application, this class notifies. |
javax.servlet.http package interface
Some of the important interface of this package are listed below:
Interface |
Overview |
HttpServletRequest |
The object of this interface is used to get the information from the user under http protocol. |
HttpServletResponse |
The object of this interface is used to provide the response of the request under http protocol. |
HttpSession |
This interface is used to track the information of users. |
HttpSessionAttributeListener |
This interface notifies if any change occurs in HttpSession attribute. |
HttpSessionListener |
This interface notifies if any changes occur in HttpSession lifecycle. |
javax.servlet.http package classes
Some of the important interface of this package are listed below.
Class |
Overview |
HttpServlet |
This class is used to create servlet class. |
Cookie |
This class is used to maintain the session of the state. |
HttpSessionEvent |
This class notifies if any changes occur in the session of web application. |
HttpSessionBindingEvent |
This class notifies when any attribute is bound, unbound or replaced in a session. |