1、byte[]转换为InputStream
InputStream sbs = new ByteArrayInputStream(byte[] buf);

2、InputStream转换为InputStreambyte[]
ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
byte[] buff = new byte[100]; //buff用于存放循环读取的临时数据
int rc = 0;
while ((rc = inStream.read(buff, 0, 100)) > 0) {
swapStream.write(buff, 0, rc);
}
byte[] in_b = swapStream.toByteArray(); //in_b为转换之后的结果