Reading Bytes From Any InputStream
Most of the time, we do get available bytes in one stroke by calling read() API in InputStream.
long length = is.available();
byte[] bytes = new byte[(int) length];
is.read(bytes);
System.out.println(new String(bytes));
The above given code may not work for InputStream which reads data from socket. Means, this will not read full data from the stream, reason could be
- network delay in transmitting content
- mounted filesystem unlinked
- message size is exceeds TCP window size
- etc.,
Hence, the following code will make sure and helps us to check whether all the bytes are received or not.
public static byte[] getBytesFromInputStream(InputStream is)
throws IOException {
// Get the size of the file
long length = is.available();
if (length > Integer.MAX_VALUE) {
// File is too large
}
// Create the byte array to hold the data
byte[] bytes = new byte[(int) length];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
offset += numRead;
}
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file ");
}
// Close the input stream and return bytes
is.close();
return bytes;
}
Read more : Reverse Reading
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