字符编码过滤器

**背景：**中文乱码配置
在web.xml 文件中增加配置

<filter>
 <filter-name>encoding</filter-name>
  <filter-class>org.springframework.web.filter.Charac
terEncodingFilter</filter-class>
 <init-param>
  <param-name>encoding</param-name>
   <param-value>utf-8</param-value>
   </init-param>
    </filter>
     	<filter-mapping>
      	<filter-name>encoding</filter-name> 
     	 <url-pattern>/*</url-pattern>
    </filter-mapping>