Spring mvc basics

1. Start the server and load some configuration files

DispatcherServlet object is created 
springmvc.xml is loaded 
HelloController object is created 
InternalResourceViewResolver View resolver object is created to 
enable annotation support for mvc

Corresponding code

Initial website page index.jsp

<%--
  Created by IntelliJ IDEA.
  User: ASUS
  Date: 2020/4/11
  Time: 12:56
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

    <h3> Getting started </ h3>

    <a href="hello">12</a>

</body>
</html>

View Code

springmvc.xml configuration file: enable annotation support, enable annotation bean scanning package, instantiate the view parser object,

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!-Open the annotation scanning package->
    <context:component-scan base-package="cn.cast"/>

    <!-View parser object->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

    <!-Turn on SpringMVC framework annotation support->
    <mvc:annotation-driven/>

</beans>

View Code

web.xml configuration file: configure DispatcherServlet (interceptor) and its properties

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>

  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!-Load configuration file->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <!-Load the configuration file when the server starts->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <!-Intercept all requests->
    <url-pattern>/</url-pattern>
  </servlet-mapping>

</web-app>

View Code

HelloContoller class: used to handle / hello requests

package cn.cast.controller;

/**
 * Controller class
 */

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public  class HelloController {
     / * *
     * Request mapping annotation: path = / hello
     * / hello becomes the request path for this method execution
     * @return
     */
    @RequestMapping(path = "/hello")
    public String sayHello(){
        System.out.println("Hello SpringMVC");
        return "success";
    }

}

View Code

success.jsp: response page returned after processing the request

<%--
  Created by IntelliJ IDEA.
  User: ASUS
  Date: 2020/4/11
  Time: 13:15
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

    < h3 > Successful entry </ h3 >

</body>
</html>

View Code

2. Background processing request

　　Received <a href="hello"> 12 </a> request in the background

　　-> All requests are intercepted by DispatcherServlet

　　-> The interceptor calls HelloController's sayHello (already configured to respond to / hello requests) method

　　-> The method returns "success" after execution

　　-> Interceptor parses "success" through the view parser, plus prefix and suffix, make the page jump to success.jsp

　　-> The corresponding package returned is this success.jsp

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