上网搜索原因如下:
Q: In Tomcat, I got a "Post data too big" error.
A: Apache Tomcat by default sets a limit on the maximum size of HTTP POST requests it accepts.
In Tomcat 5, this limit is set to 2097152 (2 Mb).
When you try to upload files or post forms that are larger than 2 MB, this error can occur.
The solution is to reconfigure Tomcat to accept larger POST requests, either by increasing
the limit, or by disabling it.
This can be done by editing Tomcat's server.xml.
In the element, add an attribute "maxPostSize" and set a larger value (in bytes) to increase the limit.
Setting it to 0 will disable the size check.
解决的办法是修改 tomcat 的配置文件 $TOMCAT_HOME$/conf/server.xml,找到里面的Connector标签,在该标签中添加 "maxPostSize" 属性,将该属性值设置成你想要的最大值,单位是字节,如果你把这个值设置为 0(maxPostSize="0"),tomcat 将不再检查 POST 的大小
如下
<Connector URIEncoding="UTF-8" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" enableLookups="false" maxHttpHeaderSize="8192" maxSpareThreads="75" maxThreads="150" minSpareThreads="5" port="8080" redirectPort="8443" maxPostSize="0"/>