个人理解 就是为了防止在前端输入的数据到了后台发生乱码
直接复制到web.xml里面就可以使用 亲测 能用!!!
<!-- 前端过滤器设置字符编码 -->
<filter>
<filter-name>encoding-filter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding-filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
推荐网址:https://blog.csdn.net/uhgagnu/article/details/59103027