当前系统只支持UTF编码接入，通过encodingFilter进行筛选过滤，如下：
<filter>
<filter-name>encodingFilter</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>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
但是最新接入的商户需要使用GBK编码，为了减少对已有系统的影响，考虑到filter的传递性，于是增加如下filter对应新的url pattern
<filter>
<filter-name>gbkEncodingFilter</filter-name>
<filter-class>
org.springframework.web.filter.CharacterEncodingFilter
</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>GBK</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>gbkEncodingFilter</filter-name>
<url-pattern>/gbkurl</url-pattern>
</filter-mapping>
通过这样设置，至少保证从request到应用的链路不会产生乱码，同样有其他需求可以通过新增对应字符编码的filter和url mapping来实现。
目前能想到的就这个了，以后有好的再考虑优化
