request.getInputstrem方法的注意点

读取一次后，流已经被读完，且不能reset，如需多次读取，需手动的缓存

http://ayaoxinchao.iteye.com/blog/2110902   《request.getInputStream()只能获取一次的问题》

From what I've read by Googling, any of the following methods will render getInputStream empty if called first:

• getParameter
• getParameterNames
• getParameterValues
• getParameterMap

http://stackoverflow.com/questions/6780562/tomcat-filter-adversely-affecting-request-input-stream-input-stream-empty

http://stackoverflow.com/questions/4449096/how-to-read-inputstream-multiple-times