xml配置utf-8编码过滤器

  <filter>
      <filter-name>encoding</filter-name>
      <filter-class>com.web.filter.Encoding</filter-class>
      <init-param>
          <param-name>charset</param-name>
          <param-value>utf-8</param-value>
      </init-param>
  </filter>

  <filter-mapping>
      <filter-name>encoding</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>