public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain filterChain) throws IOException, ServletException {

    //过滤中文
    request.setCharacterEncoding("utf-8");
    filterChain.doFilter(request, response);
}

<servlet>
  <description>chinese encoding</description>
  <display-name>This is the display name of my J2EE component</display-name>
  <servlet-name>EncodingFilter</servlet-name>
  <servlet-class>com.nichao.filter.EncodingFilter</servlet-class>
 </servlet>

 <servlet-mapping>
  <servlet-name>EncodingFilter</servlet-name>
  <url-pattern>/EncodingFilter</url-pattern>
 </servlet-mapping> -->
 ```
 将其修改为
 ```
 <filter>
 <filter-name>EncodingFilter</filter-name>
 <filter-class>com.sina.filter.EncodingFilter</filter-class>
 </filter>

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