SpringMVC is a front-end control framework that will replace the traditional Servlet work. Spring MVC is a big component of Spring.
Disadvantages of Serclet :
1- 1 servlet needs to configure at least 8 lines of xml . If there are many large-scale system servlets , the entire xml configuration will become very cumbersome.
2-It is cumbersome for the servlet to obtain the data passed in by the user. Each time it receives a data, it needs to write request.getParameter("name")
3- The parameter types obtained by the server are all String types, and the programmer needs to manually convert the types.
4- For an operation, you need to write a Servlet for processing
5- The method of servlet is single, only doget () doPost ();
Components of SpringMVC:
1- The front controller is only responsible for forwarding the request and response objects
2- The processor mapper matches the URL to the corresponding Controller
3- The processor adapter executes the corresponding handel
4- The view parser converts the logical name of the page into the corresponding specific page path
Spring MVC calling process:
1- The client sends a request request
2- Request handler mapper to handle handler (find matching Controller class)
3- Return the Controller class that can handle it
4- The request processor adapter executes the handler (internally executed according to the matching rules)
5-Execute handler (Controller-service--dao)
6- Return the processing result and return the ModelAndView object (model represents the processed data View represents the logical name hello of the page)
7- Return the ModelAndView object to the front controller
8- Request the view parser to parse the View object (splicing the logical name of the page into a complete page path /WEB-INF/hello.jsp)
9- Return the full page path to the front controller again
10- Fill the model data into the Request field in the page
Getting Started
1- Import the jar package:
2- Configure Dis patcherServlet - in web.xml
3- Write the core configuration file of spring MVC
Name specification: By default, the name of the configuration file is + the name of the servlet + " -servlet.xml " ----> (springmvc-servlet.xml)
4- Implement the Controller interface
5- Configure the view resolver
springMVC modifies the location of the core configuration file:
<servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--Modify the location of the configuration file--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping>
The annotation form of springMVC:
1-Start springMVC annotation
2- Use the annotation @RequestMapping
Get the request object and the response object:
Solve the problem of Chinese garbled characters:
<!--Solve the problem of Chinese garbled characters--> <filter> <filter-name>characterEncoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>characterEncoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>