本文整理汇总了Java中org.apache.hadoop.util.DataChecksum.writeValue方法的典型用法代码示例。如果您正苦于以下问题：Java DataChecksum.writeValue方法的具体用法？Java DataChecksum.writeValue怎么用？Java DataChecksum.writeValue使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类org.apache.hadoop.util.DataChecksum的用法示例。
在下文中一共展示了DataChecksum.writeValue方法的2个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: calcPartialBlockChecksum
import org.apache.hadoop.util.DataChecksum; //导入方法依赖的package包/类
private MD5Hash calcPartialBlockChecksum(ExtendedBlock block,
long requestLength, DataChecksum checksum, DataInputStream checksumIn)
throws IOException {
final int bytesPerCRC = checksum.getBytesPerChecksum();
final int csize = checksum.getChecksumSize();
final byte[] buffer = new byte[4*1024];
MessageDigest digester = MD5Hash.getDigester();
long remaining = requestLength / bytesPerCRC * csize;
for (int toDigest = 0; remaining > 0; remaining -= toDigest) {
toDigest = checksumIn.read(buffer, 0,
(int) Math.min(remaining, buffer.length));
if (toDigest < 0) {
break;
}
digester.update(buffer, 0, toDigest);
}
int partialLength = (int) (requestLength % bytesPerCRC);
if (partialLength > 0) {
byte[] buf = new byte[partialLength];
final InputStream blockIn = datanode.data.getBlockInputStream(block,
requestLength - partialLength);
try {
// Get the CRC of the partialLength.
IOUtils.readFully(blockIn, buf, 0, partialLength);
} finally {
IOUtils.closeStream(blockIn);
}
checksum.update(buf, 0, partialLength);
byte[] partialCrc = new byte[csize];
checksum.writeValue(partialCrc, 0, true);
digester.update(partialCrc);
}
return new MD5Hash(digester.digest());
}
示例2: truncateBlock
import org.apache.hadoop.util.DataChecksum; //导入方法依赖的package包/类
static private void truncateBlock(File blockFile, File metaFile,
long oldlen, long newlen) throws IOException {
LOG.info("truncateBlock: blockFile=" + blockFile
+ ", metaFile=" + metaFile
+ ", oldlen=" + oldlen
+ ", newlen=" + newlen);
if (newlen == oldlen) {
return;
}
if (newlen > oldlen) {
throw new IOException("Cannot truncate block to from oldlen (=" + oldlen
+ ") to newlen (=" + newlen + ")");
}
DataChecksum dcs = BlockMetadataHeader.readHeader(metaFile).getChecksum();
int checksumsize = dcs.getChecksumSize();
int bpc = dcs.getBytesPerChecksum();
long n = (newlen - 1)/bpc + 1;
long newmetalen = BlockMetadataHeader.getHeaderSize() + n*checksumsize;
long lastchunkoffset = (n - 1)*bpc;
int lastchunksize = (int)(newlen - lastchunkoffset);
byte[] b = new byte[Math.max(lastchunksize, checksumsize)];
RandomAccessFile blockRAF = new RandomAccessFile(blockFile, "rw");
try {
//truncate blockFile
blockRAF.setLength(newlen);
//read last chunk
blockRAF.seek(lastchunkoffset);
blockRAF.readFully(b, 0, lastchunksize);
} finally {
blockRAF.close();
}
//compute checksum
dcs.update(b, 0, lastchunksize);
dcs.writeValue(b, 0, false);
//update metaFile
RandomAccessFile metaRAF = new RandomAccessFile(metaFile, "rw");
try {
metaRAF.setLength(newmetalen);
metaRAF.seek(newmetalen - checksumsize);
metaRAF.write(b, 0, checksumsize);
} finally {
metaRAF.close();
}
}