1.POST请求乱码
解决方法:在web.xml文件中添加post编码过滤器
<filter>
<filter-name>CharacterEncodingFilter</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>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
2.获取null的请求参数
解决方法:将entype="nultipart/from-data" 去掉
3.400 Bad Request.
解决方法:https://blog.csdn.net/tb3039450/article/details/53787187