According to Tomcat7's documentation, setting maxPostSize in Connector to a value less than or equal to 0 may disable the limit of the size of a post request. But in fact, when I set it to 0, uploading a file in multipart/form-data enctype still got the error of exceeding the max size limit. When I set it to -1, no limit occurs, but other strange things happened.

If I set maxPostSize to -1, and leave the text field "description" to blank, it responses:maxPostSize=0 results in a limit of zero. -1 is the correct value for no limit. I'll get that fixed shortly.

说明：在tomcat7.0，使用了servlet3.0, maxPostSize属性，如果设置0，并不是无限提交，如果设置-1，是无限的正确的值。

maxPostSize="-1"

参考：http://www.cnblogs.com/luoruiyuan/p/6518524.html