Key Points -
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MVC is a design pattern where an application is can be divided into 3 layers so that each layer has exactly one responsibility and does not know much about other layers.
Model - Looks into application's business logic and interactions with database.
View - Looks into presentation part on how to display. Also, view technologies can be changed easily or upgraded as view is not dependent on other layers.
Controller - Acts as a middleman in which additional logic can be added for controlling role based access (example). Also, takes command from View layer ( add data, edit data, delete data, etc) and gets the work done from Model layer.(request/response)
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Dispatcher Servlet -
1. Web application works with client-server architecture. Client sends a request for some resource and server responds with a resource.
2. We need a servlet which process request with the help of other classes (data + business logic) and send response.
3. DispatcherServlet handles all requests in a central place and sends request to the controller which in turn processes (store/load) data based on the business rules.
4. DispatcherServlet uses FrontController design pattern which means handling of an application will be done at a central place.
5. Example web.xml
<web-app>
<servlet>
<servlet-name>example</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>example</servlet-name>
<url-pattern>*.form</url-pattern>
</servlet-mapping>
</web-app>
(Taken from http://docs.spring.io/spring-framework/docs/2.0.x/reference/mvc.html)
6. URLs ending with .form will be handled by example dispatcher servlet.
7. Spring framework looks for a file named [servlet-name]-servlet.xml in the WEB-INF directory of web application. Also, creates beans defined in this xml file.
As per above point 5 - file name will be example-servlet.xml
<context:component-scan base-package="com.xyz.xyz" />
<!-- Configuration defining views files -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/views/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
8. If you want to give different servlet name or different location (other than default location i.e.,WEB-INF directory, then add following details in the web.xml file
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/example-servlet.xml
</param-value>
</context-param>
-----------------------------------------------------------------------------------------------------------------------
MVC is a design pattern where an application is can be divided into 3 layers so that each layer has exactly one responsibility and does not know much about other layers.
Model - Looks into application's business logic and interactions with database.
View - Looks into presentation part on how to display. Also, view technologies can be changed easily or upgraded as view is not dependent on other layers.
Controller - Acts as a middleman in which additional logic can be added for controlling role based access (example). Also, takes command from View layer ( add data, edit data, delete data, etc) and gets the work done from Model layer.(request/response)
------------------------------------------------------------------------------------------------------------------------
Dispatcher Servlet -
1. Web application works with client-server architecture. Client sends a request for some resource and server responds with a resource.
2. We need a servlet which process request with the help of other classes (data + business logic) and send response.
3. DispatcherServlet handles all requests in a central place and sends request to the controller which in turn processes (store/load) data based on the business rules.
4. DispatcherServlet uses FrontController design pattern which means handling of an application will be done at a central place.
5. Example web.xml
<web-app>
<servlet>
<servlet-name>example</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>example</servlet-name>
<url-pattern>*.form</url-pattern>
</servlet-mapping>
</web-app>
(Taken from http://docs.spring.io/spring-framework/docs/2.0.x/reference/mvc.html)
6. URLs ending with .form will be handled by example dispatcher servlet.
7. Spring framework looks for a file named [servlet-name]-servlet.xml in the WEB-INF directory of web application. Also, creates beans defined in this xml file.
As per above point 5 - file name will be example-servlet.xml
<context:component-scan base-package="com.xyz.xyz" />
<!-- Configuration defining views files -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/views/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
8. If you want to give different servlet name or different location (other than default location i.e.,WEB-INF directory, then add following details in the web.xml file
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/example-servlet.xml
</param-value>
</context-param>
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