java.io.RandomAccessFile.length()方法的使用及代码示例

x33g5p2x  于2022-01-28 转载在 其他  
字(10.3k)|赞(0)|评价(0)|浏览(250)

本文整理了Java中java.io.RandomAccessFile.length方法的一些代码示例，展示了RandomAccessFile.length的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。RandomAccessFile.length方法的具体详情如下：
包路径：java.io.RandomAccessFile
类名称：RandomAccessFile
方法名：length

RandomAccessFile.length介绍

[英]Returns the length of this file in bytes.
[中]返回此文件的长度（字节）。

代码示例

代码示例来源：origin: libgdx/libgdx

public long length () {
  try {
    if (!exists()) {
      return 0;
    }
    RandomAccessFile raf = new RandomAccessFile(this, "r");
    long len = raf.length();
    raf.close();
    return len;
  } catch (IOException e) {
    return 0;
  }
}

代码示例来源：origin: stackoverflow.com

import java.io.RandomAccessFile;
RandomAccessFile f = new RandomAccessFile(fileName, "r");
byte[] b = new byte[(int)f.length()];
f.readFully(b);

代码示例来源：origin: apache/storm

private byte[] readFile(File file) throws IOException {
  RandomAccessFile raf = new RandomAccessFile(file, "r");
  byte[] buffer = new byte[(int) raf.length()];
  raf.readFully(buffer);
  raf.close();
  return buffer;
}

代码示例来源：origin: Codecademy/EventHub

@Override
 public DmaIdList build(String filename) {
  try {
   File file = new File(filename);
   if (!file.exists()) {
    //noinspection ResultOfMethodCallIgnored
    file.getParentFile().mkdirs();
    //noinspection ResultOfMethodCallIgnored
    file.createNewFile();
    try (RandomAccessFile raf = new RandomAccessFile(new File(filename), "rw")) {
     raf.setLength(DmaIdList.META_DATA_SIZE + defaultCapacity * DmaIdList.SIZE_OF_DATA);
    }
   }
   try (RandomAccessFile raf = new RandomAccessFile(new File(filename), "rw")) {
    FileChannel channel = raf.getChannel();
    MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, raf.length());
    int numRecords = buffer.getInt();
    int capacity = (int) (raf.length() - DmaIdList.META_DATA_SIZE) / DmaIdList.SIZE_OF_DATA;
    buffer.position(DmaIdList.META_DATA_SIZE + numRecords * DmaIdList.SIZE_OF_DATA);
    return new DmaIdList(filename, buffer, numRecords, capacity);
   }
  } catch (IOException e) {
   throw new RuntimeException(e);
  }
 }
}

代码示例来源：origin: GitLqr/LQRWeChat

File f = new File(path);
RandomAccessFile raf = null;
try {
  if (f.exists()) {
    if (!append) {
      f.delete();
    raf = new RandomAccessFile(f, "rw");
    raf.seek(raf.length());
    raf.write(content);
    res = true;

代码示例来源：origin: alibaba/fescar

@Override
public boolean hasRemaining(boolean isHistory) {
  File file = null;
  RandomAccessFile raf = null;
  long currentOffset = 0;
  if (isHistory) {
    file = new File(hisFullFileName);
    currentOffset = recoverHisOffset;
  } else {
    file = new File(currFullFileName);
    currentOffset = recoverCurrOffset;
  }
  try {
    raf = new RandomAccessFile(file, "r");
    return currentOffset < raf.length();
  } catch (IOException exx) {
  } finally {
    closeFile(raf);
  }
  return false;
}

代码示例来源：origin: libgdx/libgdx

void addPatchFile(String zipFileName) throws IOException {
  File file = new File(zipFileName);
  RandomAccessFile f = new RandomAccessFile(file, "r");
  long fileLength = f.length();
    f.close();
    throw new java.io.IOException();
  f.seek(0);
  f.seek(searchStart);
  ByteBuffer bbuf = ByteBuffer.allocate((int) readAmount);
  byte[] buffer = bbuf.array();
  MappedByteBuffer directoryMap = f.getChannel().map(
      FileChannel.MapMode.READ_ONLY, dirOffset, dirSize);
  directoryMap.order(ByteOrder.LITTLE_ENDIAN);

代码示例来源：origin: apache/ignite

/**
 * @throws Exception If failed.
 */
@Test
public void testReadLineFromBinaryFile() throws Exception {
  File file = new File(FILE_PATH);
  file.deleteOnExit();
  RandomAccessFile raf = new RandomAccessFile(file, "rw");
  byte[] b = new byte[100];
  Arrays.fill(b, (byte)10);
  raf.write(b);
  raf.writeBytes("swap-spaces/space1/b53b3a3d6ab90ce0268229151c9bde11|" +
    "b53b3a3d6ab90ce0268229151c9bde11|1315392441288" + U.nl());
  raf.writeBytes("swap-spaces/space1/b53b3a3d6ab90ce0268229151c9bde11|" +
    "b53b3a3d6ab90ce0268229151c9bde11|1315392441288" + U.nl());
  raf.write(b);
  raf.writeBytes("test" + U.nl());
  raf.getFD().sync();
  raf.seek(0);
  while (raf.getFilePointer() < raf.length()) {
    String s = raf.readLine();
    X.println("String: " + s + ";");
    X.println("String length: " + s.length());
    X.println("File pointer: " + raf.getFilePointer());
  }
}

代码示例来源：origin: stackoverflow.com

public void insert(String filename, long offset, byte[] content) {
 RandomAccessFile r = new RandomAccessFile(new File(filename), "rw");
 RandomAccessFile rtemp = new RandomAccessFile(new File(filename + "~"), "rw");
 long fileSize = r.length();
 FileChannel sourceChannel = r.getChannel();
 FileChannel targetChannel = rtemp.getChannel();
 sourceChannel.transferTo(offset, (fileSize - offset), targetChannel);
 sourceChannel.truncate(offset);
 r.seek(offset);
 r.write(content);
 long newOffset = r.getFilePointer();
 targetChannel.position(0L);
 sourceChannel.transferFrom(targetChannel, newOffset, (fileSize - offset));
 sourceChannel.close();
 targetChannel.close();
}

代码示例来源：origin: apache/storm

/**
 * Given a zip File input it will return its size Only works for zip files whose uncompressed size is less than 4 GB, otherwise returns
 * the size module 2^32, per gzip specifications
 *
 * @param myFile The zip file as input
 * @return zip file size as a long
 *
 * @throws IOException
 */
public static long zipFileSize(File myFile) throws IOException {
  try (RandomAccessFile raf = new RandomAccessFile(myFile, "r")) {
    raf.seek(raf.length() - 4);
    long b4 = raf.read();
    long b3 = raf.read();
    long b2 = raf.read();
    long b1 = raf.read();
    return (b1 << 24) | (b2 << 16) + (b3 << 8) + b4;
  }
}

代码示例来源：origin: apache/incubator-druid

/**
  * Open a stream to a file.
  *
  * @param offset If zero, stream the entire log. If positive, read from this byte position onwards. If negative,
  *               read this many bytes from the end of the file.
  *
  * @return input supplier for this log, if available from this provider
  */
 public static InputStream streamFile(final File file, final long offset) throws IOException
 {
  final RandomAccessFile raf = new RandomAccessFile(file, "r");
  final long rafLength = raf.length();
  if (offset > 0) {
   raf.seek(offset);
  } else if (offset < 0 && offset < rafLength) {
   raf.seek(Math.max(0, rafLength + offset));
  }
  return Channels.newInputStream(raf.getChannel());
 }
}

代码示例来源：origin: apache/flume

SetMultimap<Long, Long> inflights = HashMultimap.create();
if (!fileChannel.isOpen()) {
 file = new RandomAccessFile(inflightEventsFile, "rw");
 fileChannel = file.getChannel();
if (file.length() == 0) {
 return inflights;
file.seek(0);
byte[] checksum = new byte[16];
file.read(checksum);
ByteBuffer buffer = ByteBuffer.allocate(
  (int) (file.length() - file.getFilePointer()));
fileChannel.read(buffer);
byte[] fileChecksum = digest.digest(buffer.array());

代码示例来源：origin: Alluxio/alluxio

/**
 * Constructs a Block reader given the file path of the block.
 *
 * @param path file path of the block
 */
public LocalFileBlockReader(String path) throws IOException {
 mFilePath = Preconditions.checkNotNull(path, "path");
 mLocalFile = mCloser.register(new RandomAccessFile(mFilePath, "r"));
 mFileSize = mLocalFile.length();
 mLocalFileChannel = mCloser.register(mLocalFile.getChannel());
}

代码示例来源：origin: net.java.dev.jna/jna

private void runDetection() throws IOException {
  RandomAccessFile raf = new RandomAccessFile(filename, "r");
  try {
    if (raf.length() > 4) {
      byte[] magic = new byte[4];
      raf.seek(0);
      raf.read(magic);
      if (Arrays.equals(magic, ELF_MAGIC)) {
        ELF = true;
      return;
    raf.seek(4);
    _64Bit = sizeIndicator == EI_CLASS_64BIT;
    bigEndian = endianessIndicator == EI_DATA_BIG_ENDIAN;
    raf.seek(0);
    raf.getChannel().read(headerData, 0);
      raf.close();
    } catch (IOException ex) {

代码示例来源：origin: robovm/robovm

/**
 * Skips over {@code count} bytes in this file. Less than {@code count}
 * bytes are skipped if the end of the file is reached or an exception is
 * thrown during the operation. Nothing is done if {@code count} is
 * negative.
 *
 * @param count
 *            the number of bytes to skip.
 * @return the number of bytes actually skipped.
 * @throws IOException
 *             if this file is closed or another I/O error occurs.
 */
public int skipBytes(int count) throws IOException {
  if (count > 0) {
    long currentPos = getFilePointer(), eof = length();
    int newCount = (int) ((currentPos + count > eof) ? eof - currentPos : count);
    seek(currentPos + newCount);
    return newCount;
  }
  return 0;
}

代码示例来源：origin: jenkinsci/jenkins

try (RandomAccessFile raf = new RandomAccessFile(file, "r")) {
  long len = raf.length();
  raf.seek(pos);

代码示例来源：origin: checkstyle/checkstyle

/**
 * Checks whether the content provided by the Reader ends with the platform
 * specific line separator.
 * @param randomAccessFile The reader for the content to check
 * @return boolean Whether the content ends with a line separator
 * @throws IOException When an IO error occurred while reading from the
 *         provided reader
 */
private boolean endsWithNewline(RandomAccessFile randomAccessFile)
    throws IOException {
  final boolean result;
  final int len = lineSeparator.length();
  if (randomAccessFile.length() < len) {
    result = false;
  }
  else {
    randomAccessFile.seek(randomAccessFile.length() - len);
    final byte[] lastBytes = new byte[len];
    final int readBytes = randomAccessFile.read(lastBytes);
    if (readBytes != len) {
      throw new IOException("Unable to read " + len + " bytes, got "
          + readBytes);
    }
    result = lineSeparator.matches(lastBytes);
  }
  return result;
}

代码示例来源：origin: apache/activemq

public void corruptRecoveryLocation(Location recoveryPosition) throws IOException {
  DataFile dataFile = getDataFile(recoveryPosition);
  // with corruption on recovery we have no faith in the content - slip to the next batch record or eof
  DataFileAccessor reader = accessorPool.openDataFileAccessor(dataFile);
  try {
    RandomAccessFile randomAccessFile = reader.getRaf().getRaf();
    randomAccessFile.seek(recoveryPosition.getOffset() + 1);
    byte[] data = new byte[getWriteBatchSize()];
    ByteSequence bs = new ByteSequence(data, 0, randomAccessFile.read(data));
    int nextOffset = 0;
    if (findNextBatchRecord(bs, randomAccessFile) >= 0) {
      nextOffset = Math.toIntExact(randomAccessFile.getFilePointer() - bs.remaining());
    } else {
      nextOffset = Math.toIntExact(randomAccessFile.length());
    }
    Sequence sequence = new Sequence(recoveryPosition.getOffset(), nextOffset - 1);
    LOG.warn("Corrupt journal records found in '{}' between offsets: {}", dataFile.getFile(), sequence);
    // skip corruption on getNextLocation
    recoveryPosition.setOffset(nextOffset);
    recoveryPosition.setSize(-1);
    dataFile.corruptedBlocks.add(sequence);
  } catch (IOException e) {
  } finally {
    accessorPool.closeDataFileAccessor(reader);
  }
}

代码示例来源：origin: stackoverflow.com

RandomAccessFile raf = new RandomAccessFile("path to ur delimited file", "rw");
FileChannel fileChannel = raf.getChannel(); 
raf.readLine();     
raf.seek(raf.getFilePointer());         
int len = (int) (raf.length() - raf.getFilePointer());
byte[] bytearr = new byte[len];         
raf.readFully(bytearr, 0, len);         
fileChannel.truncate(0);            
raf.write(bytearr,0,len);

代码示例来源：origin: apache/ignite

/**
 * @param name File path.
 * @param size Expected file size. If size is 0, the existing size will be used.
 * @throws IOException If failed to open the file or memory-map it.
 */
public MappedFile(File name, long size) throws IOException {
  file = new RandomAccessFile(name, "rw");
  try {
    if (size == 0)
      size = file.length();
    else
      file.setLength(size);
    addr = map(file, MAP_RW, 0, size);
    this.size = size;
  } catch (IOException e) {
    file.close();
    throw e;
  }
}

内容来源于网络，如有侵权，请联系作者删除！

randomaccessfile

相关文章

    查看更多

    热门标签

    更多
    JavaquerypythonNode开发语言requestUtil数据库Table后端算法LoggerMessageElementParser

    最新文章

    更多

    RandomAccessFile类方法

    • 蜀ICP备13028337号-1 大数据知识库 https://www.saoniuhuo.com © All rights reserved
    • 本站内容来源互联网,如果侵犯您的权益请联系我们删除, 联系方式：448109455@qq.com