java.io.RandomAccessFile Java Examples

private static void largeFile(String fileName) throws IOException {
    if (!new File(fileName).exists()) {
        System.out.println("not found: " + fileName);
        return;
    }
    RandomAccessFile f = new RandomAccessFile(fileName, "r");
    byte[] data = new byte[(int) f.length()];
    f.readFully(data);
    HashSet<Text> set = new HashSet<Text>(40 * 1024 * 1024);
    int end = Text.indexOf(data, 0, '\n');
    Text t = new Text(data, 0, end);
    long time = System.currentTimeMillis();
    while (true) {
        set.add(t);
        if (end >= data.length - 1) {
            break;
        }
        int start = end + 1;
        end = Text.indexOf(data, start, '\n');
        t = new Text(data, start, end - start);
        long now = System.currentTimeMillis();
        if (now - time > 2000) {
            System.out.println("size: " + set.size());
            time = now;
        }
    }
    System.out.println("file: " + fileName);
    System.out.println("size: " + set.size());

    test(set, 8, 14);
    test(set, 8, 10);
    test(set, 8, 16);
    test(set, 8, 12);
}
 

public static void printJdpPacket(JdpJmxPacket p) {
    if (getVerbose()) {
        try {
            RandomAccessFile f = new RandomAccessFile("out.dmp", "rw");
            f.write(p.getPacketData());
            f.close();
        } catch (IOException e) {
            System.out.println("Can't write a dump file: " + e);
        }

        System.out.println("Id: " + p.getId());
        System.out.println("Jmx: " + p.getJmxServiceUrl());
        System.out.println("Main: " + p.getMainClass());
        System.out.println("InstanceName: " + p.getInstanceName());
        System.out.println("ProccessId: " + p.getProcessId());
        System.out.println("BroadcastInterval: " + p.getBroadcastInterval());
        System.out.println("Rmi Hostname: " + p.getRmiHostname());

        System.out.flush();
    }
}
 

/**
 * java.io.RandomAccessFile#writeChars(java.lang.String)
 */
public void test_writeCharsLjava_lang_String() throws IOException {
    RandomAccessFile raf = new java.io.RandomAccessFile(fileName, "rw");
    raf.writeChars(unihw);
    char[] hchars = new char[unihw.length()];
    unihw.getChars(0, unihw.length(), hchars, 0);
    raf.seek(0);
    for (int i = 0; i < hchars.length; i++)
        assertEquals("Test 1: Incorrect character written or read at index " + i + ";",
                hchars[i], raf.readChar());
    raf.close();
    try {
        raf.writeChars("Already closed.");
        fail("Test 2: IOException expected.");
    } catch (IOException e) {
        // Expected.
    }
}
 

public FileChange(File file) throws IOException {
	if(!file.exists()) 
	{
		System.out.println("File not found");
		throw new IOException();
	}
	this.file = file;
	RandomAccessFile rsf = new RandomAccessFile(this.file, "rw");
	this.data = new byte[(int) rsf.length()];
	rsf.read(data);
	int pos = 0;
	while (pos < data.length) {
		instBuf.add(data[pos++]);
	}
	rsf.close();
	getLength();
}
 

public BaseRegionLoader(LevelProvider level, int regionX, int regionZ, String ext) {
    try {
        this.x = regionX;
        this.z = regionZ;
        this.levelProvider = level;
        this.filePath = this.levelProvider.getPath() + "region/r." + regionX + "." + regionZ + "." + ext;
        this.file = new File(this.filePath);
        boolean exists = this.file.exists();
        if (!exists) {
            file.createNewFile();
        }
        this.randomAccessFile = new RandomAccessFile(this.filePath, "rw");
        if (!exists) {
            this.createBlank();
        } else {
            this.loadLocationTable();
        }

        this.lastUsed = System.currentTimeMillis();
    } catch (IOException e) {
        throw new RuntimeException(e);
    }

}
 

public TwoBitParser(File f) throws Exception {
	this.f = f;
	raf = new RandomAccessFile(f,"r");
	long sign = readFourBytes();
	if(sign==0x1A412743) {
		logger.debug("2bit: Normal number architecture");
	}
	else if(sign==0x4327411A) {
		reverse = true;
		logger.debug("2bit: Reverse number architecture");
	}
	else throw new Exception("Wrong start signature in 2BIT format");
	readFourBytes();
	int seq_qnt = (int)readFourBytes();
	readFourBytes();
	seq_names = new String[seq_qnt];
	for(int i=0;i<seq_qnt;i++) {
		int name_len = raf.read();
		char[] chars = new char[name_len];
		for(int j=0;j<name_len;j++) chars[j] = (char)raf.read();
		seq_names[i] = new String(chars);
		long pos = readFourBytes();
		seq2pos.put(seq_names[i],pos);
		logger.debug("2bit: Sequence name=[{}], pos={}", seq_names[i], pos);
	}
}
 

@Test
public void testRead() throws IOException {
    // 1、创建随机访问流对象
    RandomAccessFile raf = new RandomAccessFile("raf.txt", "rw");
    int i = raf.readInt();
    System.out.println(i);
    // 该文件指针可以通过 getFilePointer方法读取，并通过 seek 方法设置。
    System.out.println("当前文件的指针位置是：" + raf.getFilePointer());

    char ch = raf.readChar();
    System.out.println(ch);
    System.out.println("当前文件的指针位置是：" + raf.getFilePointer());

    String s = raf.readUTF();
    System.out.println(s);
    System.out.println("当前文件的指针位置是：" + raf.getFilePointer());

    // 我不想重头开始了，我就要读取a，怎么办呢?
    raf.seek(4);
    ch = raf.readChar();
    System.out.println(ch);
}
 

private OutputStream openOutputStream(boolean appendToFile, final long byteOffset) throws IOException {
	throwClosed();
	throwOpenDirectory();

	if (this.opendOutputStream != null) {
		throw new IOException("OutputStream already opened");
	}
	/**
	 * Trying to open more than one InputStream or more than one
	 * OutputStream from a StreamConnection causes an IOException.
	 */
	RandomAccessFile raf = new RandomAccessFile(file, "rw");
	raf.seek(byteOffset);
	return new FileOutputStream(raf.getFD()) {
		@Override
		public void close() throws IOException {
			FileSystemFileConnection.this.opendOutputStream = null;
			super.close();
		}
	};
}
 

/**
 * Marks the index as dirty. Writes an invalid file header, and sets the dirty
 * flag which will cause the new file header to be serialized when the index is
 * disposed.
 */
protected void markDirty() {
    RandomAccessFile randomAccessFile = fRandomAccessFile;
    if (fIsDirty || randomAccessFile == null) {
        return;
    }
    try {
        // Write an invalid version until the very last moment when dispose
        // the index. This is how we know if it's corrupted or not.
        randomAccessFile.seek(0);
        randomAccessFile.writeInt(INVALID_VERSION);
    } catch (IOException e) {
        Activator.logError(MessageFormat.format(Messages.IOErrorWritingHeader, fFile), e);
    }
    fIsDirty = true;
}
 

/**
 * Check to see if a pattern matches the saved pattern. If no pattern
 * exists, always returns true.
 * 
 * @param pattern
 *            The pattern to check.
 * @return Whether the pattern matches the stored one.
 */
public boolean checkPattern(List<LockPatternView.Cell> pattern) {
	try {
		// Read all the bytes from the file
		RandomAccessFile raf = new RandomAccessFile(sLockPatternFilename,
				"r");
		final byte[] stored = new byte[(int) raf.length()];
		int got = raf.read(stored, 0, stored.length);
		raf.close();
		if (got <= 0) {
			return true;
		}
		// Compare the hash from the file with the entered pattern's hash
		return Arrays.equals(stored,
				LockPatternUtils.patternToHash(pattern));
	} catch (FileNotFoundException fnfe) {
		return true;
	} catch (IOException ioe) {
		return true;
	}
}
 

private static boolean readSection(RandomAccessFile in, ElfData elf) throws IOException {
    byte[] bytes = new byte[SECTION_HEADER_SIZE];
    in.seek(elf.e_shoff);

    for (int i = 0; i < elf.e_shnum; ++i) {
        in.readFully(bytes);

        // wrap bytes in a ByteBuffer to force endianess
        ByteBuffer buffer = ByteBuffer.wrap(bytes);
        buffer.order(elf.order);

        int sh_type = buffer.getInt(4); /* Section type */
        if (sh_type != SHT_ARM_ATTRIBUTES)
            continue;

        elf.sh_offset = buffer.getInt(16);  /* Section file offset */
        elf.sh_size = buffer.getInt(20);    /* Section size in bytes */
        return true;
    }

    return false;
}
 

private void passN() throws IOException
{

    // Get FV from file
    randomAccessFile = new RandomAccessFile(getCacheFile(), "r");

    while (randomAccessFile.getFilePointer() < randomAccessFile.length())
    {
        int recordLength = (int) randomAccessFile.readLong();
        packBuffer = growIfNeeded(packBuffer, recordLength);
        randomAccessFile.read(packBuffer, 0, recordLength);
        FeatureVector fv = toFeatureVector();
        // add to ring buffer
        addWithProb(fv);

    }

    randomAccessFile.close();

    signalEndEpoch();

}
 

/**
 * java.io.RandomAccessFile#readLine()
 */
public void test_readLine() throws IOException {
    // Test for method java.lang.String java.io.RandomAccessFile.readLine()
    RandomAccessFile raf = new java.io.RandomAccessFile(fileName, "rw");
    String s = "Goodbye\nCruel\nWorld\n";
    raf.write(s.getBytes(), 0, s.length());
    raf.seek(0);

    assertEquals("Test 1: Incorrect line read;", "Goodbye", raf.readLine());
    assertEquals("Test 2: Incorrect line read;", "Cruel", raf.readLine());
    assertEquals("Test 3: Incorrect line read;", "World", raf.readLine());
    assertNull("Test 4: Incorrect line read; null expected.", raf.readLine());

    raf.close();
    try {
        raf.readLine();
        fail("Test 5: IOException expected.");
    } catch (IOException e) {
        // Expected.
    }

}
 

@VisibleForTesting
void refreshFileConnection(int accessFileNum, IOException ioe) throws IOException {
  ReentrantLock channelLock = channelLocks[accessFileNum];
  channelLock.lock();
  try {
    FileChannel fileChannel = fileChannels[accessFileNum];
    if (fileChannel != null) {
      // Don't re-open a channel if we were waiting on another
      // thread to re-open the channel and it is now open.
      if (fileChannel.isOpen()) {
        return;
      }
      fileChannel.close();
    }
    LOG.warn("Caught ClosedChannelException accessing BucketCache, reopening file: "
        + filePaths[accessFileNum], ioe);
    rafs[accessFileNum] = new RandomAccessFile(filePaths[accessFileNum], "rw");
    fileChannels[accessFileNum] = rafs[accessFileNum].getChannel();
  } finally{
    channelLock.unlock();
  }
}
 

private void openRAF() {
  if (DiskStoreImpl.PREALLOCATE_IF) {
    openRAF2();
    return;
  }
  try {
    this.ifRAF = new RandomAccessFile(this.ifFile, getFileMode());
    long len = this.ifRAF.length();
    if (len != 0) {
      this.ifRAF.seek(len);
    }
  } catch (IOException ex) {
    throw new DiskAccessException(
        LocalizedStrings.DiskRegion_COULD_NOT_OPEN_0.toLocalizedString(this.ifFile
            .getPath()), ex, this.parent);
  }
}
 

private static ByteBuffer createByteBufferFile(int size) {
    try {
        if (tmpDir != null && logger.isLoggable(Level.INFO)) {
            logger.log(Level.INFO, "tmpDir = {0}", tmpDir.getAbsoluteFile());
        }
        File tmpFile = File.createTempFile("pmd","tmp", tmpDir);
        if (logger.isLoggable(Level.INFO)) {
            logger.log(Level.INFO, "tmpFile = {0}", tmpFile.getAbsoluteFile());
        }
        RandomAccessFile os = new RandomAccessFile(tmpFile, "rw");
        os.seek(size);
        os.write(0);
        FileChannel ch = os.getChannel();
        MappedByteBuffer  bb = ch.map(MapMode.READ_WRITE, 0, size);
        os.close();
        ch.close();
        tmpFile.delete();
        bb.order(ByteOrder.nativeOrder());
        return bb;
    } catch(IOException ex) {
        throw new RuntimeException(ex);
    }
}
 

@Override
public byte[] load(String key) {
  String filename = makeFilename(key);

  File file = new File(filename);
  if (!file.exists()) {
    return null;
  }

  byte[] data = null;

  try {
    RandomAccessFile f = new RandomAccessFile(file, "r");
    data = new byte[(int) file.length()];
    f.readFully(data);
    f.close();
  } catch (Exception e) {
    e.printStackTrace();
  }

  return data;
}
 

/**
 * Saves track properties by modifying only file tail.
 */
public void saveProperties(FileDataSource source) throws Exception {
    Track track = source.tracks.get(0);
    // Prepare new properties tail
    ByteBuffer buffer = ByteBuffer.allocate(getSerializedPropertiesSize(track));
    CodedOutputStream output = CodedOutputStream.newInstance(buffer);
    output.writeBytes(FIELD_NAME, ByteString.copyFromUtf8(track.name));
    output.writeUInt32(FIELD_COLOR, track.style.color);
    output.writeFloat(FIELD_WIDTH, track.style.width);
    output.flush();
    // Modify tail of file
    File file = new File(source.path);
    long createTime = file.lastModified();
    RandomAccessFile access = new RandomAccessFile(file, "rw");
    access.setLength(source.propertiesOffset + 1);
    access.seek(source.propertiesOffset);
    access.write(buffer.array());
    access.close();
    //noinspection ResultOfMethodCallIgnored
    file.setLastModified(createTime);
}
 

public static void printJdpPacket(JdpJmxPacket p) {
    if (getVerbose()) {
        try {
            RandomAccessFile f = new RandomAccessFile("out.dmp", "rw");
            f.write(p.getPacketData());
            f.close();
        } catch (IOException e) {
            System.out.println("Can't write a dump file: " + e);
        }

        System.out.println("Id: " + p.getId());
        System.out.println("Jmx: " + p.getJmxServiceUrl());
        System.out.println("Main: " + p.getMainClass());
        System.out.println("InstanceName: " + p.getInstanceName());
        System.out.println("ProccessId: " + p.getProcessId());
        System.out.println("BroadcastInterval: " + p.getBroadcastInterval());
        System.out.println("Rmi Hostname: " + p.getRmiHostname());

        System.out.flush();
    }
}
 

@Test (expected = InvalidProtocolBufferException.class)
public void testCorruptMeta() throws Throwable {
  EventQueueBackingStore backingStore = EventQueueBackingStoreFactory.
          get(checkpoint, 10, "test");
  backingStore.close();
  Assert.assertTrue(checkpoint.exists());
  File metaFile = Serialization.getMetaDataFile(checkpoint);
  Assert.assertTrue(metaFile.length() != 0);
  RandomAccessFile writer = new RandomAccessFile(metaFile, "rw");
  writer.seek(10);
  writer.writeLong(new Random().nextLong());
  writer.getFD().sync();
  writer.close();
  try {
    backingStore = EventQueueBackingStoreFactory.get(checkpoint, 10, "test");
  } catch (BadCheckpointException ex) {
    throw ex.getCause();
  }
}
 

public SegmentImpl(String folder, String id, long off, long len, long dwn) throws IOException {
	this.id = id;
	this.id = id;
	this.startOffset = off;
	this.folder = folder;
	this.length = len;
	this.downloaded = dwn;
	this.time1 = System.currentTimeMillis();
	this.time2 = time1;
	this.bytesRead1 = dwn;
	this.bytesRead2 = dwn;
	try {
		outStream = new RandomAccessFile(new File(folder, id), "rw");
		outStream.seek(dwn);
		Logger.log("File opened " + id);
	} catch (IOException e) {
		Logger.log(e);
		if (outStream != null) {
			outStream.close();
		}
		throw new IOException(e);
	}
	this.config = Config.getInstance();
}
 

@Override // Storage
public boolean isPreUpgradableLayout(StorageDirectory sd) throws IOException {
  if (disablePreUpgradableLayoutCheck) {
    return false;
  }

  File oldImageDir = new File(sd.getRoot(), "image");
  if (!oldImageDir.exists()) {
    return false;
  }
  // check the layout version inside the image file
  File oldF = new File(oldImageDir, "fsimage");
  RandomAccessFile oldFile = new RandomAccessFile(oldF, "rws");
  try {
    oldFile.seek(0);
    int oldVersion = oldFile.readInt();
    oldFile.close();
    oldFile = null;
    if (oldVersion < LAST_PRE_UPGRADE_LAYOUT_VERSION)
      return false;
  } finally {
    IOUtils.cleanup(LOG, oldFile);
  }
  return true;
}
 

public static void transferFile(
        final File file, 
        final OutputStream out,
        final Progress progress) throws IOException {
    RandomAccessFile in = null;
    
    try {
        transferData(in = new RandomAccessFile(file, "r"), out, progress);
    } finally {
        if (in != null) {
            try {
                in.close();
            } catch (IOException e) {
                ErrorManager.notifyDebug("Cannot close raf", e);
            }
        }
    }
}
 

public static void verifyLossOccurredForStream(final String aeronDirectoryName, final int streamId)
    throws IOException
{
    final File lossReportFile = LossReportUtil.file(aeronDirectoryName);
    assertTrue(lossReportFile.exists());

    MappedByteBuffer mappedByteBuffer = null;

    try (RandomAccessFile file = new RandomAccessFile(lossReportFile, "r");
        FileChannel channel = file.getChannel())
    {
        mappedByteBuffer = channel.map(READ_ONLY, 0, channel.size());
        final AtomicBuffer buffer = new UnsafeBuffer(mappedByteBuffer);

        final LossReportReader.EntryConsumer lossEntryConsumer = mock(LossReportReader.EntryConsumer.class);
        LossReportReader.read(buffer, lossEntryConsumer);

        verify(lossEntryConsumer).accept(
            longThat((l) -> l > 0),
            longThat((l) -> l > 0),
            anyLong(),
            anyLong(),
            anyInt(),
            eq(streamId),
            any(),
            any());
    }
    finally
    {
        IoUtil.unmap(mappedByteBuffer);
    }
}
 

protected MemoryMappedFileManager(final RandomAccessFile file, final String fileName, final OutputStream os,
        final boolean immediateFlush, final long position, final int regionLength, final String advertiseURI,
        final Layout<? extends Serializable> layout, final boolean writeHeader) throws IOException {
    super(os, fileName, layout, writeHeader, ByteBuffer.wrap(new byte[0]));
    this.immediateFlush = immediateFlush;
    this.randomAccessFile = Objects.requireNonNull(file, "RandomAccessFile");
    this.regionLength = regionLength;
    this.advertiseURI = advertiseURI;
    this.isEndOfBatch.set(Boolean.FALSE);
    this.mappedBuffer = mmap(randomAccessFile.getChannel(), getFileName(), position, regionLength);
    this.byteBuffer = mappedBuffer;
    this.mappingOffset = position;
}
 

/**
 * @param file
 *            file to check
 * @return true if file seems to be gzipped.
 * @throws CbmException
 *             if error
 */
public static boolean isGZipped(String file) throws CbmException {
	try (RandomAccessFile raf = new RandomAccessFile(file, "r")) {
		return GZIPInputStream.GZIP_MAGIC == (raf.read() & 0xff | ((raf.read() << 8) & 0xff00));
	} catch (IOException e) {
		throw new CbmException("Failed to open zip header. " + e.getMessage(), e);
	}
}
 

protected static byte[] readDelimitedBuffer(RandomAccessFile fileHandle)
    throws IOException {
  int length = fileHandle.readInt();
  Preconditions.checkState(length >= 0, Integer.toHexString(length));
  byte[] buffer = new byte[length];
  fileHandle.readFully(buffer);
  return buffer;
}
 

private byte[] extractLaunchScript(File file) throws IOException
{
    final int startZipOffset;
    try (RandomAccessFile raf = new RandomAccessFile(file, "r"))
    {
        int nextZipFileHeaderPos = 0;
        int matches = 0;
        while (matches != ZIP_FILE_HEADER.length)
        {
            int b = raf.read();
            if (b == -1)
            {
                throw new IOException("Cannot extract launch script");
            }
            if (b == ZIP_FILE_HEADER[nextZipFileHeaderPos])
            {
                matches++;
                nextZipFileHeaderPos++;
            }
            else
            {
                matches = 0;
                nextZipFileHeaderPos = 0;
            }
        }
        startZipOffset = (int) raf.getFilePointer() - ZIP_FILE_HEADER.length;
    }
    final byte[] launchScript = new byte[startZipOffset];
    try (FileInputStream is = new FileInputStream(file))
    {
        is.read(launchScript);
    }
    return launchScript;
}
 

private static String readInstallationFile(File installation) throws IOException {
    RandomAccessFile f = new RandomAccessFile(installation, "r");
    byte[] bytes = new byte[(int) f.length()];
    f.readFully(bytes);
    f.close();
    return new String(bytes);
}
 

public FileLockData(String filePath) {
	file = new File(filePath);
	try {
		randomAccessFile = new RandomAccessFile(file, "rw");
		fileChannel = randomAccessFile.getChannel();
	} catch (FileNotFoundException e) {
		e.printStackTrace();
	}
}