The basic steps to create a SpringMVC project

Create an empty Maven project as the parent project, delete src
Add related dependencies for this parent project

spring,servlet,jsp,jstl…

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>

Prevent Maven static resource export problems

<build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

Create a new blank Maven subproject
Right click and select add framework support

Choose web application

In this way, a web project was successfully created

Configure web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <!--注册servlet-->
    <servlet>
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--通过初始化参数指定SpringMVC配置文件的位置，进行关联-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!-- 启动顺序，数字越小，启动越早 -->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!--所有请求都会被Spring拦截-->
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>


</web-app>

The difference between / and /*: <url-pattern> / </ url-pattern> will not match the .jsp, only for the requests we write; that is, the .jsp will not enter the Spring DispatcherServlet class. <url-pattern> /* </ url-pattern> will match *.jsp, and the DispatcherServlet class of spring will appear again when returning to the jsp view, causing the corresponding controller not to be found, so a 404 error is reported.

- Pay attention to the issue of web.xml version, ask for the latest version!
- Register DispatcherServlet
- Associated SpringMVC configuration file
- Startup level is 1
- The mapping path is / [Do not use /*, it will 404]

8. Add springMVC configuration file

Add the springmvc-servlet.xml configuration file under resources. The configuration form is similar to the basic configuration of the Spring container. In order to support the annotation-based IOC, the automatic scanning package function is set. The specific configuration information is as follows:

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

    <!-- 自动扫描包，让指定包下的注解生效,由IOC容器统一管理 -->
    <context:component-scan base-package="top.faroz.controller"/>
    <!-- 让Spring MVC不处理静态资源 -->
    <mvc:default-servlet-handler />
    <!--
    支持mvc注解驱动
        在spring中一般采用@RequestMapping注解来完成映射关系
        要想使@RequestMapping注解生效
        必须向上下文中注册DefaultAnnotationHandlerMapping
        和一个AnnotationMethodHandlerAdapter实例
        这两个实例分别在类级别和方法级别处理。
        而annotation-driven配置帮助我们自动完成上述两个实例的注入。
     -->
    <mvc:annotation-driven />

    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          id="internalResourceViewResolver">
        <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <!-- 后缀 -->
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

In the view resolver, we store all the views in the /WEB-INF/ directory , which can ensure the security of the view, because the files in this directory cannot be directly accessed by the client .
- Let the IOC comments take effect
- Static resource filtering: HTML. JS. CSS. Pictures, videos...
- Annotation-driven MVC
- Configure view resolver

9. Create the controller

Write a java control class

@Controller
@RequestMapping("/HelloController")
public class HelloController {
    
    

    //真实访问地址 : 项目名/HelloController/hello
    @RequestMapping("/hello")
    public String sayHello(Model model) {
    
    
        //向模型中添加属性msg与值，可以在JSP页面中取出并渲染
        model.addAttribute("msg","hello,SpringMVC");
        //web-inf/jsp/hello.jsp
        return "hello";
    }
}

@Controller is to allow the Spring IOC container to be automatically scanned when it is initialized;
@RequestMapping is to map the request path, here because there are mappings on the class and method, it should be /HelloController/hello when accessed;
The method declares the parameters of the Model type to bring the data in the Action to the view;
Results hello method returns the name of the view, together with the prefix and suffix profile-INF into the WEB / JSP / hello .jsp. Previously, the following paragraph in springmvc-servlet.xml was used for this:

Create the view layer
Create hello.jsp in the WEB-INF/jsp directory, the view can directly retrieve and display the information brought back from the Controller;
The value or object stored in the Model can be retrieved through EL representation;

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
   <title>SpringMVC</title>
</head>
<body>
${msg}
</body>
</html>

Configure Tomcat
To run, enter the URL http://localhost:8080/HelloController/hello

Found that the result is 404

Here must pay attention to a guide package problem

Guide package problem

Add lib

Select all here, then click OK

At this time, we restarted the project and found that it was OK

The basic steps to create a SpringMVC project

Guess you like