Netty 대용량파일 전송

SocketClientHandler.java

package net.dsdstudio.sharebox.client;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.RandomAccessFile;
import java.text.NumberFormat;

/**
 * Created with IntelliJ IDEA.
 * User: bhkim
 * Date: 12. 9. 23.
 * Time: 오전 3:53
 */
public class SocketClientHandler extends SimpleChannelUpstreamHandler {
    Logger logger = LoggerFactory.getLogger(getClass());

    private String filepath;


    public SocketClientHandler(String filepath) {
        this.filepath = filepath;
    }

    /**
     * Protocol 초기화
     * [4byte|?byte|8byte|chunk ?byte]
     * [filenamelen|filenamedata|filedatalen|filedatadatachunks]
     *
     * @param file
     * @return
     */
    private ChannelBuffer initializeProtocol(File file) {
        logger.debug("Generate Protocol Buffer");
        ChannelBuffer buffer = ChannelBuffers.buffer(file.getName().length() + 12);
        buffer.writeInt(file.getName().length());
        buffer.writeBytes(file.getName().getBytes());
        buffer.writeLong(file.length());
        logger.debug("buffer index : {}", buffer.writerIndex());
        return buffer;
    }

    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        logger.debug("channel connected " + ctx.getChannel().getRemoteAddress());

        final Channel channel = ctx.getChannel();
        final File file = new File(filepath);


        logger.debug("local address : {}", channel.getLocalAddress());

        // header write
        ChannelFuture future = channel.write(this.initializeProtocol(file));
        future.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                logger.debug("header transfer complete. transfer data");
                // RandomAccess file을 만든다. FileRegion을 만들기 위함임
                RandomAccessFile raf = new RandomAccessFile(file, "r");

                // FileRegion을 이용하여 전체를 바로 전송하지않고 내부적으로 chunk 단위로 전송한다.
                // 대용량일때는 64k정도로 유지하는것으로 추정됨. 트래픽에따라 chunk 단위가 유동적으로 변함
                final FileRegion region = new DefaultFileRegion(raf.getChannel(), 0, file.length(), true);
                final ChannelFuture channelFuture = channel.write(region);

                logger.debug("file size : {}", region.getCount());
                channelFuture.addListener(new ChannelFutureProgressListener() {
                    @Override
                    public void operationProgressed(ChannelFuture future, long amount, long current, long total) throws Exception {
                        logger.debug(String.format("%s : %d / %d (+%d)%n", file.getAbsolutePath(), current, total, amount));
                    }

                    @Override
                    public void operationComplete(ChannelFuture future) throws Exception {
                        logger.debug("file transfer completed ! [{}:{} bytes]", file.getName(), NumberFormat.getInstance().format(file.length()));
                        // File 자원 해제
                        region.releaseExternalResources();
                    }
                });
            }
        });
    }

    public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        logger.debug("channel disconnected");
        ctx.sendUpstream(e);
    }


    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
        logger.error("", e.getCause());
        ctx.getChannel().close();

    }
}