Java FileChannel.map方法代码示例

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
/** Copia un fichero.
 * @param source Fichero origen con el contenido que queremos copiar.
 * @param dest Fichero destino de los datos.
 * @throws IOException SI ocurre algun problema durante la copia */
public static void copyFile(final File source, final File dest) throws IOException {
    if (source == null || dest == null) {
        throw new IllegalArgumentException("Ni origen ni destino de la copia pueden ser nulos"); //$NON-NLS-1$
    }

    final FileInputStream is = new FileInputStream(source);
    final FileOutputStream os = new FileOutputStream(dest);
    final FileChannel in = is.getChannel();
    final FileChannel out = os.getChannel();
    final MappedByteBuffer buf = in.map(FileChannel.MapMode.READ_ONLY, 0, in.size());
    out.write(buf);

    in.close();
    out.close();
    is.close();
    os.close();

}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
public ByteBuffer call() throws Exception {
    ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
    buff = ByteBuffer.allocate(bufferSize);
    serverSocketChannel.socket().bind(new InetSocketAddress(port));
    RandomAccessFile temp = new RandomAccessFile(tempName, "rw");
    MappedByteBuffer b;
    while (!stop.isLocked()) {
        sync=0;
        SocketChannel socketChannel = serverSocketChannel.accept();
        socketChannel.read(buff);
        FileChannel channel = temp.getChannel();
        channel.write(buff);
        if (!pause.isLocked()) {
            b = channel.map(MapMode.READ_WRITE, 0, (long) bufferSize);
            sync = 1;
            if(sync==2){
            b.clear();
            }
        }
        buff.clear();
    }
    temp.close();
    return null;
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
/**
 * Insert new metadata into file by using memory mapped file, and if fails write in chunks
 * <p>
 * But this is problematic on 32bit systems for large flac files may not be able to map a contiguous address space large enough
 * for a large audio size , so no longer used since better to go straight to using chunks
 *
 * @param tag
 * @param fc
 * @param blockInfo
 * @param flacStream
 * @param neededRoom
 * @param availableRoom
 * @throws IOException
 * @throws UnsupportedEncodingException
 */
private void insertTagAndShift(File file, Tag tag, FileChannel fc, MetadataBlockInfo blockInfo, FlacStreamReader flacStream, int neededRoom, int availableRoom) throws IOException, UnsupportedEncodingException {
    int headerLength = flacStream.getStartOfFlacInFile() + FlacStreamReader.FLAC_STREAM_IDENTIFIER_LENGTH + MetadataBlockHeader.HEADER_LENGTH // this should be the length of the block header for the stream info
            + MetadataBlockDataStreamInfo.STREAM_INFO_DATA_LENGTH;
    long targetSizeBeforeAudioData = headerLength + neededRoom + FlacTagCreator.DEFAULT_PADDING;
    long remainderTargetSize = fc.size() - (headerLength + availableRoom);
    long totalTargetSize = targetSizeBeforeAudioData + remainderTargetSize;

    MappedByteBuffer mappedFile = null;
    try {
        //Use ByteBuffer
        mappedFile = fc.map(MapMode.READ_WRITE, 0, totalTargetSize);
        insertTagAndShiftViaMappedByteBuffer(tag, mappedFile, fc, targetSizeBeforeAudioData, totalTargetSize, blockInfo, flacStream, neededRoom, availableRoom);
    } catch (IOException ioe) {
        //#175: Flac Map error on write
        if (mappedFile == null) {
            insertUsingChunks(file, tag, fc, blockInfo, flacStream, neededRoom + FlacTagCreator.DEFAULT_PADDING, availableRoom);
        } else {
            logger.log(Level.SEVERE, ioe.getMessage(), ioe);
            throw ioe;
        }
    }
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
public CommandLogReader(String path) {
    FileChannel roChannel = null;
    ByteBuffer readonlybuffer = null;
    
    File f = new File(path);
    try {
        roChannel = new RandomAccessFile(f, "r").getChannel();
        LOG.trace("File Size :"+roChannel.size());            

        
        readonlybuffer = roChannel.map(FileChannel.MapMode.READ_ONLY, 0, (int)roChannel.size());
        LOG.trace("Opened file :"+f.getAbsolutePath());            
        LOG.trace("Size :"+readonlybuffer.remaining());            
        
    } catch (IOException ex) {
        LOG.trace("Failed to open file :"+f.getAbsolutePath());            
        throw new RuntimeException(ex);
    }
    assert(readonlybuffer != null);
    this.fd = new FastDeserializer(readonlybuffer);
            
    this.procedures = this.readHeader();        
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
/**
 * 将字节数组写入文件
 *
 * @param file    文件
 * @param bytes   字节数组
 * @param append  是否追加在文件末
 * @param isForce 是否写入文件
 * @return {@code true}: 写入成功<br>{@code false}: 写入失败
 */
public static boolean writeFileFromBytesByMap(final File file, final byte[] bytes, final boolean append, final boolean isForce) {
    if (bytes == null || !createOrExistsFile(file)) return false;
    FileChannel fc = null;
    try {
        fc = new FileOutputStream(file, append).getChannel();
        MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_WRITE, fc.size(), bytes.length);
        mbb.put(bytes);
        if (isForce) mbb.force();
        return true;
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    } finally {
        CloseUtils.closeIO(fc);
    }
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
public static String getFileMD5String(String path) {
    try {
        File file = new File(path);
        FileInputStream in = new FileInputStream(file);
        FileChannel ch = in.getChannel();
        MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
        MessageDigest messageDigest = MessageDigest.getInstance("MD5");
        messageDigest.update(byteBuffer);
        return bufferToHex(messageDigest.digest());
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
/**
 * Read a file to string
 * 
 * @author erickson
 * @link http://stackoverflow.com/a/326440
 * 
 * @param file
 * @return
 * @throws IOException
 */
public static String readFile(final File file) throws IOException {
	final FileInputStream stream = new FileInputStream(file);
	try {
		final FileChannel fc = stream.getChannel();
		final ByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
		return Charset.forName(ENCODING).decode(bb).toString();
	} finally {
		stream.close();
	}
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
/**
 * Converts the file into a byte[].
 * @param infile The File you want to specify
 * @return a byte array
 * @throws IOException if something goes wrong reading the file.
 */
private byte[] mapFileIn(File infile) throws IOException{
	FileInputStream fis = new FileInputStream(infile);
	try{
		FileChannel fc = fis.getChannel(); // Get the file's size and then map it into memory
		int sz = (int)fc.size();
		MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, sz);
		byte[] data2 = new byte[bb.remaining()];
		bb.get(data2);
		return data2;
	}
	finally{//Ensures resources are closed regardless of whether the action suceeded
		fis.close();
	}
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
private void CreateMappedBytes(FileChannel InChannel) throws IOException {
	try {
		if (_IPv4Buffer == null) {
			final long _IPv4Bytes = (long)_IPv4ColumnSize * (long)_DBCount;
			_IPv4Offset = _BaseAddr - 1;
			_IPv4Buffer = InChannel.map(FileChannel.MapMode.READ_ONLY, _IPv4Offset, _IPv4Bytes);
			_IPv4Buffer.order(ByteOrder.LITTLE_ENDIAN);
			_MapDataOffset = _IPv4Offset + _IPv4Bytes;
		}
		
		if (_DBCountIPv6 > 0 && _IPv6Buffer == null) {
			final long _IPv6Bytes = (long)_IPv6ColumnSize * (long)_DBCountIPv6;
			_IPv6Offset = _BaseAddrIPv6 - 1;
			_IPv6Buffer = InChannel.map(FileChannel.MapMode.READ_ONLY, _IPv6Offset, _IPv6Bytes);
			_IPv6Buffer.order(ByteOrder.LITTLE_ENDIAN);
			_MapDataOffset = _IPv6Offset + _IPv6Bytes;
		}
		
		if (_MapDataBuffer == null) {
			_MapDataBuffer = InChannel.map(FileChannel.MapMode.READ_ONLY, _MapDataOffset, InChannel.size() - _MapDataOffset);
			_MapDataBuffer.order(ByteOrder.LITTLE_ENDIAN);
		}
	}
	catch (IOException Ex) {
		throw Ex;
	}
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
@Override
public ByteBuffer nioByteBuffer() throws IOException {
  FileChannel channel = null;
  try {
    channel = new RandomAccessFile(file, "r").getChannel();
    // Just copy the buffer if it's sufficiently small, as memory mapping has a high overhead.
    if (length < conf.memoryMapBytes()) {
      ByteBuffer buf = ByteBuffer.allocate((int) length);
      channel.position(offset);
      while (buf.remaining() != 0) {
        if (channel.read(buf) == -1) {
          throw new IOException(String.format("Reached EOF before filling buffer\n" +
            "offset=%s\nfile=%s\nbuf.remaining=%s",
            offset, file.getAbsoluteFile(), buf.remaining()));
        }
      }
      buf.flip();
      return buf;
    } else {
      return channel.map(FileChannel.MapMode.READ_ONLY, offset, length);
    }
  } catch (IOException e) {
    try {
      if (channel != null) {
        long size = channel.size();
        throw new IOException("Error in reading " + this + " (actual file length " + size + ")",
          e);
      }
    } catch (IOException ignored) {
      // ignore
    }
    throw new IOException("Error in opening " + this, e);
  } finally {
    JavaUtils.closeQuietly(channel);
  }
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
private static MappedByteBuffer map(RandomAccessFile raf, MapMode mode, long size)
    throws IOException {
  Closer closer = Closer.create();
  try {
    FileChannel channel = closer.register(raf.getChannel());
    return channel.map(mode, 0, size);
  } catch (Throwable e) {
    throw closer.rethrow(e);
  } finally {
    closer.close();
  }
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
private FunctionEntry updateFunctionCode(final String functionName, final FileChannel fileChannel) throws IOException {
    final MappedByteBuffer buffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, fileChannel.size());
    buffer.load();
    final UpdateFunctionCodeRequest request = new UpdateFunctionCodeRequest()
            .withFunctionName(functionName)
            .withZipFile(buffer);
    final UpdateFunctionCodeResult result = awsLambdaClient.updateFunctionCode(request);
    return new FunctionEntry(result);
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
private TrieDictionary(File data) throws IOException {
    this.array = null;

    FileInputStream ins = new FileInputStream(data);
    FileChannel channel = ins.getChannel();
    
    try {
        this.buffer = channel.map(MapMode.READ_ONLY, 0, channel.size());
    } finally {
        channel.close();
        ins.close();
    }
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
HprofMappedByteBuffer(File dumpFile) throws IOException {
    FileInputStream fis = new FileInputStream(dumpFile);
    FileChannel channel = fis.getChannel();
    length = channel.size();
    dumpBuffer = channel.map(FileChannel.MapMode.READ_ONLY, 0, length);
    channel.close();
    readHeader();
}
 

import java.nio.channels.FileChannel; //导入方法依赖的package包/类
public static void copy(File srcPath, File dstPath) throws IOException {
	if (srcPath.isDirectory()) {
		if (!dstPath.exists()) {
			boolean result = dstPath.mkdir();
			if (!result) {
				throw new IOException("Unable to create directoy: " + dstPath);
			}
		}

		String[] files = srcPath.list();
		for (String file : files) {
			copy(new File(srcPath, file), new File(dstPath, file));
		}
	} else {
		if (srcPath.exists()) {
			FileChannel in = null;
			FileChannel out = null;
			try (FileInputStream fis = new FileInputStream(srcPath);
					FileOutputStream fos = new FileOutputStream(dstPath)) {
				in = fis.getChannel();
				out = fos.getChannel();
				long size = in.size();
				MappedByteBuffer buf = in.map(FileChannel.MapMode.READ_ONLY, 0, size);
				out.write(buf);
			} finally {
				if (in != null) {
					in.close();
				}
				if (out != null) {
					out.close();
				}
			}
		}
	}
}