/**
* InputStream 转换成byte[]
* @param input
* @return
* @throws IOException
*/
private static byte[] toByteArray(InputStream input) throws IOException {
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[1024*4];
int n = 0;
while (-1 != (n = input.read(buffer))) {
output.write(buffer, 0, n);
}
return output.toByteArray();
}