request.getInputStream() 和 request.getReader()不能同時調用，否則會引發java.lang.IllegalStateException異常。
API中有寫：
getInputStream
public ServletInputStream getInputStream()
throws java.io.IOException
- Retrieves the body of the request as binary data using a
ServletInputStream. Either this method or getReader() may be called to read the body, not both.
-
- Returns:
- a
ServletInputStream object containing the body of the request
- Throws:
java.lang.IllegalStateException - if the getReader() method has already been called for this request
java.io.IOException - if an input or output exception occurred