搭建一个SSM项目 - 3:第二个S--Spring MVC

前一章 搭建一个SSM项目 - 2:第一个S--Spring

1:pom.xml添加依赖

引入Spring-mvc需要的坐标

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${springVersion}</version>
    </dependency>

下面的依赖，可以把返回的bean转成json

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.11.1</version>
    </dependency>

2:配置spring-config.xml,beans.xml

我把spring beans的配置分成两个
spring-config.xml:一个只配置只配置视图层（@Controller）
beans.xml:只配置业务层(@Service)和持久层(@Repository)
这看个人习惯。

spring-config.xml

<?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">
    <context:component-scan base-package="com.ppf" use-default-filters="false">
        <!--只扫描Controller-->
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>
    
<!--    spring -mvc 的注解开启-->
    <mvc:annotation-driven />
<!--    配置一个handler来处理静态资源-->
    <mvc:default-servlet-handler />
</beans>

beans.xml

<?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"
       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">
    <context:component-scan base-package="com.ppf">
        <!--不扫描Controller-->
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>
</beans>

2:配置web.xml

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

<!--在这个ContextLoaderListener监听器里，把beans.xml加载-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:beans.xml</param-value>
  </context-param>
  
<!--增加request和response字符集的编解码过滤器-->
  <filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <!--要使用的字符集，一般我们使用UTF-8(保险起见UTF-8最好)-->
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
    <init-param>
      <!--是否强制设置request的编码为encoding，默认false，不建议更改-->
      <param-name>forceRequestEncoding</param-name>
      <param-value>false</param-value>
    </init-param>
    <init-param>
      <!--是否强制设置response的编码为encoding，建议设置为true，下面有关于这个参数的解释-->
      <param-name>forceResponseEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
  </filter>
  
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

<!--这个是必须的，所有请求都经过这里。-->
  <servlet>
    <servlet-name>DispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring-config.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>