在project Structure删除原有的web.xml,创建其他名字的web.xml(之后改回这个名字)

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    3.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4.          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
    5.          version="4.0">
    6.     <!--添加中文编码过滤器-->
    7.     <filter>
    8.         <filter-name>filter1</filter-name>
    9.         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    10.         <!--
    11.         private String encoding;
    12.        private boolean forceRequestEncoding = false;
    13.        private boolean forceResponseEncoding = false;
    14.        -->
    15.         <init-param>
    16.             <param-name>encoding</param-name>
    17.             <param-value>UTF-8</param-value>
    18.         </init-param>
    19.         <init-param>
    20.             <param-name>forceRequestEncoding</param-name>
    21.             <param-value>true</param-value>
    22.         </init-param>
    23.         <init-param>
    24.             <param-name>forceResponseEncoding</param-name>
    25.             <param-value>true</param-value>
    26.         </init-param>
    27.     </filter>
    28.     <filter-mapping>
    29.         <filter-name>filter1</filter-name>
    30.         <url-pattern>/*</url-pattern>
    31.     </filter-mapping>
    32.     <!--注册springmvc框架-->
    33.     <servlet>
    34.         <servlet-name>springmvc</servlet-name>
    35.         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    36.         <init-param>
    37.             <param-name>contextConfigLocation</param-name>
    38.             <param-value>classpath:springmvc.xml</param-value>
    39.         </init-param>
    40.     </servlet>
    41.     <servlet-mapping>
    42.         <servlet-name>springmvc</servlet-name>
    43.         <url-pattern>/</url-pattern>
    44.     </servlet-mapping>
    45.     <!--注册spring框架,目的就是启动spring容器-->
    46.     <!--用监听器去使用-->
    47.     <listener>
    48.         <listener-class>ContextLoaderListener</listener-class>
    49.     </listener>
    50. </web-app>

    **ContextLoaderListener**我们要找源码

    在**Maven:org.springframework:spring-web:版本号**->**org.springframework.web.context.ContextLoaderListener**

    public class ContextLoaderListener extends ContextLoader implements ServletContextListener/*整个项目相关的监听器*/ {
    ...
    //初始化
    @Override
    public void contextInitialized(ServletContextEvent event) {
        initWebApplicationContext(event.getServletContext());
    }

    //销毁
    @Override
    public void contextDestroyed(ServletContextEvent event) {
        closeWebApplicationContext(event.getServletContext());
        ContextCleanupListener.cleanupAttributes(event.getServletContext());
    }
    ...
}

    我们只不过是把spring的容器放在了这个方法中，让它去启动

    <?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">
    <!--添加中文编码过滤器-->
    <filter>
        <filter-name>filter1</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <!--
        private String encoding;
       private boolean forceRequestEncoding = false;
       private boolean forceResponseEncoding = false;
       -->
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceRequestEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>filter1</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!--注册springmvc框架-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <!--注册spring框架,目的就是启动spring容器-->
    <!--用监听器去使用-->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <!--通配符表示，所有以'applicationContext_'开头的配置文件都注册-->
        <param-value>classpath:applicationContext_*.xml</param-value>
    </context-param>
</web-app>

    这就是我们web.xml文件的注册