/**
* Maps blah file with a random offset and checks to see if read from the ByteBuffer gets the
* right line number
*/
private static void testRead() throws Exception {
StringBuilder sb = new StringBuilder();
sb.setLength(4);
for (int x = 0; x < 1000; x++) {
try (FileInputStream fis = new FileInputStream(blah)) {
FileChannel fc = fis.getChannel();
long offset = generator.nextInt(10000);
long expectedResult = offset / CHARS_PER_LINE;
offset = expectedResult * CHARS_PER_LINE;
MappedByteBuffer b = fc.map(MapMode.READ_ONLY, offset, 100);
for (int i = 0; i < 4; i++) {
byte aByte = b.get(i);
sb.setCharAt(i, (char) aByte);
}
int result = Integer.parseInt(sb.toString());
if (result != expectedResult) {
err.println("I expected " + expectedResult);
err.println("I got " + result);
throw new Exception("Read test failed");
}
}
}
}
public static void main(String args[]) {
try {
aServer asr = new aServer();
// file channel.
FileInputStream is = new FileInputStream("");
is.read();
FileChannel cha = is.getChannel();
ByteBuffer bf = ByteBuffer.allocate(1024);
bf.flip();
cha.read(bf);
// Path Paths
Path pth = Paths.get("", "");
// Files some static operation.
Files.newByteChannel(pth);
Files.copy(pth, pth);
// file attribute, other different class for dos and posix system.
BasicFileAttributes bas = Files.readAttributes(pth, BasicFileAttributes.class);
bas.size();
} catch (Exception e) {
System.err.println(e);
}
System.out.println("hello ");
}
public static void main(String[] arguments) {
try {
// read byte data into a byte buffer
String data = "friends.dat";
FileInputStream inData = new FileInputStream(data);
FileChannel inChannel = inData.getChannel();
long inSize = inChannel.size();
ByteBuffer source = ByteBuffer.allocate((int) inSize);
inChannel.read(source, 0);
source.position(0);
System.out.println("Original byte data:");
for (int i = 0; source.remaining() > 0; i++) {
System.out.print(source.get() + " ");
}
// convert byte data into character data
source.position(0);
Charset ascii = Charset.forName("US-ASCII");
CharsetDecoder toAscii = ascii.newDecoder();
CharBuffer destination = toAscii.decode(source);
destination.position(0);
System.out.println("\n\nNew character data:");
for (int i = 0; destination.remaining() > 0; i++) {
System.out.print(destination.get());
}
System.out.println();
} catch (FileNotFoundException fne) {
System.out.println(fne.getMessage());
} catch (IOException ioe) {
System.out.println(ioe.getMessage());
}
}
public static void main(String args[]) throws Exception {
FileInputStream fin = new FileInputStream("readandshow.txt");
FileChannel fc = fin.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(1024);
fc.read(buffer);
buffer.flip();
int i = 0;
while (buffer.remaining() > 0) {
byte b = buffer.get();
System.out.println("Character " + i + ": " + ((char) b));
i++;
}
fin.close();
}
public static void main(String[] args) throws Exception {
File blah = File.createTempFile("blah", null);
blah.deleteOnExit();
ByteBuffer[] dstBuffers = new ByteBuffer[10];
for (int i = 0; i < 10; i++) {
dstBuffers[i] = ByteBuffer.allocateDirect(10);
dstBuffers[i].position(10);
}
FileInputStream fis = new FileInputStream(blah);
FileChannel fc = fis.getChannel();
// No space left in buffers, this should return 0
long bytesRead = fc.read(dstBuffers);
if (bytesRead != 0) throw new RuntimeException("Nonzero return from read");
fc.close();
fis.close();
}
public static void copyFileNIO(String filenameIn, String filenameOut, long kbchunks)
throws IOException {
FileInputStream in = new FileInputStream(filenameIn);
FileChannel inChannel = in.getChannel();
FileOutputStream out = new FileOutputStream(filenameOut);
FileChannel outChannel = out.getChannel();
long size = inChannel.size();
// outChannel.position(size-2);
// outChannel.write(ByteBuffer.allocate(1));
// outChannel.position(0);
if (debug)
System.out.println(
"read " + filenameIn + " len = " + size + " out starts at=" + outChannel.position());
long start = System.currentTimeMillis();
long done = 0;
while (done < size) {
long need = Math.min(kbchunks * 1000, size - done);
done += inChannel.transferTo(done, need, outChannel);
}
outChannel.close();
inChannel.close();
double took = .001 * (System.currentTimeMillis() - start);
if (debug) System.out.println(" write file= " + filenameOut + " len = " + size);
double rate = size / took / (1000 * 1000);
System.out.println(
" copyFileNIO("
+ kbchunks
+ " kb chunk) took = "
+ took
+ " sec; rate = "
+ rate
+ "Mb/sec");
}
public static void main(String[] argv) {
if (argv.length != 3) {
usage();
}
String tempFile = argv[0];
String testFile = argv[1];
int fileSize = Integer.valueOf(argv[2]).intValue();
int exitcode = 0;
int numRead;
int numThisBuf;
int numWritten;
if ((fileSize <= 0) || (fileSize % 4096 != 0)) {
System.out.println("Error: size is not a multiple of 4096!!!!!!");
System.out.println();
usage();
}
try {
int bufSize = 4096;
byte[] inBytes = new byte[bufSize];
byte[] outBytes = new byte[bufSize];
Random ioRandom = new Random(2006);
ioRandom.nextBytes(outBytes);
ByteBuffer inBuf = ByteBuffer.allocate(bufSize);
ByteBuffer outBuf = ByteBuffer.wrap(outBytes);
//
// Loop forever
//
while (true) {
//
// Write the temporary file
//
FileOutputStream fos = new FileOutputStream(tempFile);
FileChannel foc = fos.getChannel();
numWritten = 0;
while (numWritten < fileSize) {
outBuf.clear(); // sets limit to capacity & position to zero
while (outBuf.hasRemaining()) {
numWritten += foc.write(outBuf);
}
}
//
// Move to permanent location
//
FileChannel srcChannel = new FileInputStream(tempFile).getChannel();
FileChannel dstChannel = new FileOutputStream(testFile).getChannel();
dstChannel.transferFrom(srcChannel, 0, srcChannel.size());
srcChannel.close();
dstChannel.close();
boolean success = (new File(tempFile)).delete();
if (!success) {
System.out.println("Warning: unable to delete temporary file");
}
//
// Read and compare
//
FileInputStream fis = new FileInputStream(testFile);
FileChannel fic = fis.getChannel();
for (numRead = 0, numThisBuf = 0; numRead < fileSize; numThisBuf = 0) {
inBuf.rewind(); // Set the buffer position to 0
numThisBuf = fic.read(inBuf);
while (numThisBuf < bufSize) {
numThisBuf += fic.read(inBuf);
}
numRead += bufSize;
inBuf.rewind(); // Set the buffer position to 0
inBuf.get(inBytes);
boolean same = Arrays.equals(inBytes, outBytes);
if (same = false) {
System.out.println("Data read does not equal data written at " + numRead + " bytes");
}
}
}
} catch (FileNotFoundException fnfe) {
fnfe.printStackTrace(System.err);
exitcode = 1;
// break;
} catch (SecurityException se) {
se.printStackTrace(System.err);
exitcode = 1;
// break;
} catch (Throwable t) {
t.printStackTrace(System.err);
exitcode = 1;
}
System.exit(exitcode);
}
private void readFromFile(File file) throws IOException {
fis = new FileInputStream(file);
chan = fis.getChannel();
ByteBuffer buf = chan.map(FileChannel.MapMode.READ_ONLY, 0, (int) file.length());
readFromBuffer(buf);
}
/** Tests zero size file mapping */
private static void testZero() throws Exception {
try (FileInputStream fis = new FileInputStream(blah)) {
FileChannel fc = fis.getChannel();
MappedByteBuffer b = fc.map(MapMode.READ_ONLY, 0, 0);
}
}