public void streamBlockInAscii(
InetSocketAddress addr,
long blockId,
Token<BlockTokenIdentifier> accessToken,
long genStamp,
long blockSize,
long offsetIntoBlock,
long chunkSizeToView,
JspWriter out,
Configuration conf)
throws IOException {
if (chunkSizeToView == 0) return;
Socket s = new Socket();
s.connect(addr, HdfsConstants.READ_TIMEOUT);
s.setSoTimeout(HdfsConstants.READ_TIMEOUT);
long amtToRead = Math.min(chunkSizeToView, blockSize - offsetIntoBlock);
// Use the block name for file name.
BlockReader blockReader =
RemoteBlockReader.newBlockReader(
s,
addr.toString() + ":" + blockId,
blockId,
accessToken,
genStamp,
offsetIntoBlock,
amtToRead,
conf.getInt("io.file.buffer.size", 4096));
byte[] buf = new byte[(int) amtToRead];
int readOffset = 0;
int retries = 2;
while (amtToRead > 0) {
int numRead;
try {
numRead = blockReader.readAll(buf, readOffset, (int) amtToRead);
} catch (IOException e) {
retries--;
if (retries == 0) throw new IOException("Could not read data from datanode");
continue;
}
amtToRead -= numRead;
readOffset += numRead;
}
blockReader = null;
s.close();
out.print(HtmlQuoting.quoteHtmlChars(new String(buf)));
}
