What is servlet dispatcher in Java?

Asked By: Justyna Villamayor | Last Updated: 6th March, 2020
Category: technology and computing web development
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Servlet Request Dispatcher is an interface whose implementation defines that an object can dispatch requests to any resource (such as HTML, Image, JSP, Servlet etc.) on the server. To include the response of one Servlet into another (i.e. the client gets the response of both Servlets)

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Considering this, what is dispatcher servlet and how it works?

DispatcherServlet acts as front controller for Spring based web applications. It provides a mechanism for request processing where actual work is performed by configurable, delegate components. Each servlet will operate in its own namespace, loading its own application context with mappings, handlers, etc.

Secondly, what is RequestDispatcher in Servlet with example? RequestDispatcher methods with examples in Servlet. The RequestDispatcher interface defines an object that receives the request from client and dispatches it to the resource(such as servlet, JSP, HTML file).

Just so, what is RequestDispatcher in Java?

RequestDispatcher is an interface, implementation of which defines an object which can dispatch request to any resources(such as HTML, Image, JSP, Servlet) on the server.

What is the use of Servlet in Java?

A servlet is a Java programming language class that is used to extend the capabilities of servers that host applications accessed by means of a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by web servers.

39 Related Question Answers Found

Why do we need dispatcher servlet?

The DispatcherServlet is one of the important components of the Spring MVC web framework and acts as a Front Controller. The DispatcherServlet is a front controller like it provides a single entry point for a client request to Spring MVC web application and forwards request to Spring MVC controllers for processing.

Where is dispatcher servlet defined?

The DispatcherServlet is an actual Servlet (it inherits from the HttpServlet base class), and as such is declared in the web.xml of your web application. You need to map requests that you want the DispatcherServlet to handle, by using a URL mapping in the same web.xml file.

Can we have two dispatcher servlet?

Yes, a Spring MVC web application can have more than one DispatcherServlets. Each DispatcherServlet has to operate in its own namespace. It has to load its own ApplicationContext with mappings, handlers, etc. Only the root application context will be shared among these Servlets.

Does spring boot use dispatcher servlet?

Spring Boot automatically configures a spring application based on dependencies present or not present in the classpath as a jar, beans, properties, etc. Spring Boot auto-configures a Dispatcher Servlet if Spring MVC jar is on the classpath.

What is Servlet life cycle?

A servlet life cycle can be defined as the entire process from its creation till the destruction. The servlet is initialized by calling the init() method. The servlet calls service() method to process a client's request. The servlet is terminated by calling the destroy() method.

What is dispatcher servlet XML?

DispatcherServlet is the class which manages the entire request handling process. Like a normal servlet DispatcherServlet also needs to be configured in the web deployement Descriptor(web. xml). By default DispatcherServlet will look for a name dispatcher-servlet. xml to load the Spring MVC configuration.

What is the use of WebMvcConfigurerAdapter?

WebMvcConfigurerAdapter WebMvcConfigurationSupport
implements WebMvcConfigurer. Implements: Aware, ApplicationContextAware, ServletContextAware
Main purpose is to customize the default configuration. This is the main class providing the configuration behind the MVC Java config. As we see it implements the *Aware interfaces.

Does spring boot require Web XML?

Not even a web. xml file is required! When required, however, we can take control over parts of the configuration and override the conventions that Spring Boot puts in play. We will also, of course, do it a test run in the embedded Servlet container that Spring Boot provides.

What is Session Tracking?

Session Tracking is a way to maintain state (data) of an user. It is also known as session management in servlet. Http protocol is a stateless so we need to maintain state using session tracking techniques. Each time user requests to the server, server treats the request as the new request.

What is the purpose of RequestDispatcher interface?

The RequestDispatcher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp. This interface can also be used to include the content of another resource also. It is one of the way of servlet collaboration.

How do I use SendRedirect?

The sendRedirect() method of HttpServletResponse interface can be used to redirect the response to another resource i.e. it may be a Servlet, JSP or HTML file. It works on the client side because it uses the URL bar of the browser to make another request. Hence, it can work inside and outside the server.

What is difference between SendRedirect and RequestDispatcher?

The RequestDispatcher interface allows you to do a server side forward/include whereas sendRedirect() does a client side redirect. SendRedirect() will search the content between the servers. its the server side process and it is faster compare to the SendRedirect() method.

What is Servlet collaboration?

Servlet Collaboration means how one servlet can communicate with other. Sometimes servlets are to pass the common information that is to be shared directly by one servlet to another through various invocations of the methods.

What is JSP life cycle?

JSP Life Cycle is defined as translation of JSP Page into servlet as a JSP Page needs to be converted into servlet first in order to process the service requests. The Life Cycle starts with the creation of JSP and ends with the disintegration of that.

What is 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 HttpSession in Java?

javax.servlet.http. Interface HttpSession. public interface HttpSession. Provides a way to identify a user across more than one page request or visit to a Web site and to store information about that user. The servlet container uses this interface to create a session between an HTTP client and an HTTP server.

What is servlet chaining?

Servlet Chaining means the output of one servlet act as a input to another servlet. Servlet Aliasing allows us to invoke more than one servlet in sequence when the URL is opened with a common servlet alias. The Output from the last Servlet is sent back to the browser. The entire process is called Servlet Chaining.