Why servlet filter is used?

Why servlet filter is used?

A filter is an object that is invoked at the preprocessing and postprocessing of a request. It is mainly used to perform filtering tasks such as conversion, logging, compression, encryption and decryption, input validation etc.

When servlet filter is called?

A Servlet filter is an object that can intercept HTTP requests targeted at your web application. When the servlet filter is loaded the first time, its init() method is called, just like with servlets.

What is the difference between servlet and filter?

A filter is a web component on the web server that filters the request and response client and the business unit. It is giving the customized version of the request and response. Servlet is used to control the request and perform action on that particular request.

When destroy method of a filter is called?

d) The destroyer() method is called after the filter has executed. Explanation: destroy() is an end of life cycle method so it is called at the end of life cycle. 8.

What is the difference between servlets and applets?

A servlet is a Java programming language class used to extend the capabilities of a server. Applets are executed on client side. Servlets are executed on server side. Applets are used to provide interactive features to web applications that cannot be provided by HTML alone like capture mouse input etc.

When destroy method of servlet gets called?

destroy() method is called by the servlet container to indicate to a servlet that the servlet is being taken out of service. This method is only called once all threads within the servlet’s service method have exited or after a timeout period has passed.

What are the two main types of servlet?

There are two main servlet types, generic and HTTP:

• Generic servlets. Extend javax. servlet. GenericServlet. Are protocol independent.
• HTTP servlets. Extend javax. servlet. HttpServlet. Have built-in HTTP protocol support and are more useful in a Sun Java System Web Server environment.

Who maintains life cycle of servlet?

Servlet container

Who will handle servlet files?

With the Java Servlet coded, the application can be deployed to any Java application server that supports the Servlet 3.1 specification or newer. In this Java file upload example, the target server is Tomcat 9, although the latest JBoss, Jetty, WebSphere or OpenLiberty servers will also work.

How do I run a servlet file?

Call your servlet from a web browser.

1. Step 1: Create a Directory Structure under Tomcat.
2. Step 2: Write the Servlet Source Code.
3. Step 3: Compile Your Source Code.
4. Step 4: Create the Deployment Descriptor.
5. Step 5: Run Tomcat.
6. Step 6: Call Your Servlet from a Web Browser.

What is the difference between servlet context and servlet config?

ServletConfig is an object containing some initial parameters or configuration information created by Servlet Container and passed to the servlet during initialization. ServletConfig is for a particular servlet, that means one should store servlet specific information in web. xml and retrieve them using this object.

What is the extension for servlet file?

WAR (file format)

Filename extension	.war
Magic number	PK (standard ZIP file)
Developed by	Sun Microsystems
Container for	JSP, Java Servlet
Extended from	JAR

How do you write a servlet?

The steps are as follows:

1. Create a directory structure.
2. Create a Servlet.
3. Compile the Servlet.
4. Create a deployment descriptor.
5. Start the server and deploy the project.
6. Access the servlet.

What is a .JSP file?

A JSP file is a server-generated web page. It is similar to an . ASP or . PHP file, but contains Java code instead of ActiveX or PHP. The code is parsed by the web server, which generates HTML that is sent to the user’s computer.

What is generic servlet and HTTP servlet?

Defines a generic, protocol-independent servlet. To write an HTTP servlet for use on the Web, extend HttpServlet instead. GenericServlet makes writing servlets easier. It provides simple versions of the lifecycle methods init and destroy and of the methods in the ServletConfig interface.

What is the use of generic servlet?

The GenericServlet class was created to make writing servlets easier. It provides simple versions of the life-cycle methods init and destroy, and of the methods in the ServletConfig interface. It also provides a log method, from the ServletContext interface.