Netty 下载文件

package NettyDemo.file.server;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
/***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\****
* Reserved. BidPlanStructForm.java Created on 2014-8-19 Author: <a
* href=mailto:wanghouda@126.com>wanghouda
* @Title: HttpFileServer.java
* @Package NettyDemo.file.server Description: Version: 1.0
\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***/
public class HttpFileServer {
    static final int PORT = 8080;
    public static void main(String[] args) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class).handler(new LoggingHandler(LogLevel.INFO))
            .childHandler(new ChannelInitializer<SocketChannel>() {// 有连接到达时会创建一个channel
                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                    ChannelPipeline pipeline = ch.pipeline();
                    pipeline.addLast(new HttpServerCodec());
                    pipeline.addLast(new HttpObjectAggregator(65536));
                    pipeline.addLast(new ChunkedWriteHandler());
                    pipeline.addLast(new FileServerHandler());
                }
        });
            Channel ch = b.bind(PORT).sync().channel();
            System.err.println("打开浏览器,输入:  " + ("http") + "://127.0.0.1:" + PORT + '/');
            ch.closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

package NettyDemo.file.server;
import static io.netty.handler.codec.http.HttpHeaders.Names.CACHE_CONTROL;
import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;
import static io.netty.handler.codec.http.HttpHeaders.Names.DATE;
import static io.netty.handler.codec.http.HttpHeaders.Names.EXPIRES;
import static io.netty.handler.codec.http.HttpHeaders.Names.IF_MODIFIED_SINCE;
import static io.netty.handler.codec.http.HttpHeaders.Names.LAST_MODIFIED;
import static io.netty.handler.codec.http.HttpHeaders.Names.LOCATION;
import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN;
import static io.netty.handler.codec.http.HttpResponseStatus.FOUND;
import static io.netty.handler.codec.http.HttpResponseStatus.INTERNAL_SERVER_ERROR;
import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND;
import static io.netty.handler.codec.http.HttpResponseStatus.NOT_MODIFIED;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelProgressiveFuture;
import io.netty.channel.ChannelProgressiveFutureListener;
import io.netty.channel.DefaultFileRegion;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.DefaultHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpChunkedInput;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.handler.ssl.SslHandler;
import io.netty.handler.stream.ChunkedFile;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.SystemPropertyUtil;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
import java.util.regex.Pattern;
import javax.activation.MimetypesFileTypeMap;
/***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\***\****

* <href=mailto:wanghouda@126.com>wanghouda

public class FileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
    public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";
    public static final String HTTP_DATE_GMT_TIMEZONE = "GMT";
    public static final int HTTP_CACHE_SECONDS = 60;
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
        // 监测解码情况
        if (!request.getDecoderResult().isSuccess()) {
            sendError(ctx, BAD_REQUEST);
            return;
        }
        final String uri = request.getUri();
        final String path = sanitizeUri(uri);
        if (path == null) {
            sendError(ctx, FORBIDDEN);
            return;
        }
        //读取要下载的文件
        File file = new File(path);
        if (file.isHidden() || !file.exists()) {
            sendError(ctx, NOT_FOUND);
            return;
        }
        if (file.isDirectory()) {
            if (uri.endsWith("/")) {
                sendListing(ctx, file);
            } else {
                sendRedirect(ctx, uri + '/');
            }
            return;
        }
        if (!file.isFile()) {
            sendError(ctx, FORBIDDEN);
            return;
        }
        // Cache Validation
        String ifModifiedSince = request.headers().get(IF_MODIFIED_SINCE);
        if (ifModifiedSince != null && !ifModifiedSince.isEmpty()) {
            SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
            Date ifModifiedSinceDate = dateFormatter.parse(ifModifiedSince);
            // Only compare up to the second because the datetime format we send
            // to the client
            // does not have milliseconds
            long ifModifiedSinceDateSeconds = ifModifiedSinceDate.getTime() / 1000;
            long fileLastModifiedSeconds = file.lastModified() / 1000;
            if (ifModifiedSinceDateSeconds == fileLastModifiedSeconds) {
                sendNotModified(ctx);
                return;
            }
        }
        RandomAccessFile raf;
        try {
            raf = new RandomAccessFile(file, "r");
        } catch (FileNotFoundException ignore) {
            sendError(ctx, NOT_FOUND);
            return;
        }
        long fileLength = raf.length();
        HttpResponse response = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
        HttpHeaders.setContentLength(response, fileLength);
        setContentTypeHeader(response, file);
        setDateAndCacheHeaders(response, file);
        if (HttpHeaders.isKeepAlive(request)) {
            response.headers().set("CONNECTION", HttpHeaders.Values.KEEP_ALIVE);
        }
        // Write the initial line and the header.
        ctx.write(response);
        // Write the content.
        ChannelFuture sendFileFuture;
        if (ctx.pipeline().get(SslHandler.class) == null) {
            sendFileFuture = ctx.write(new DefaultFileRegion(raf.getChannel(), 0, fileLength), ctx.newProgressivePromise());
        } else {
            sendFileFuture = ctx.write(new HttpChunkedInput(new ChunkedFile(raf, 0, fileLength, 8192)), ctx.newProgressivePromise());
        }
        sendFileFuture.addListener(new ChannelProgressiveFutureListener() {
            @Override
            public void operationProgressed(ChannelProgressiveFuture future, long progress, long total) {
                if (total < 0) { // total unknown
                    System.err.println(future.channel() + " Transfer progress: " + progress);
                } else {
                    System.err.println(future.channel() + " Transfer progress: " + progress + " / " + total);
                }
            }
            @Override
            public void operationComplete(ChannelProgressiveFuture future) {
                System.err.println(future.channel() + " Transfer complete.");
            }
    });
        // Write the end marker
        ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
        // Decide whether to close the connection or not.
        if (!HttpHeaders.isKeepAlive(request)) {
            // Close the connection when the whole content is written out.
            lastContentFuture.addListener(ChannelFutureListener.CLOSE);
        }
    }
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        if (ctx.channel().isActive()) {
            sendError(ctx, INTERNAL_SERVER_ERROR);
        }
    }
    private static final Pattern INSECURE_URI = Pattern.compile(".\*[<>&\"].\*");
    private static String sanitizeUri(String uri) {
        // Decode the path.
        try {
            uri = URLDecoder.decode(uri, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new Error(e);
        }
        if (!uri.startsWith("/")) {
            return null;
        }
        // Convert file separators.
        uri = uri.replace('/', File.separatorChar);
        // Simplistic dumb security check.
        // You will have to do something serious in the production environment.
        if (uri.contains(File.separator + '.') || uri.contains('.' + File.separator) || uri.startsWith(".") || uri.endsWith(".")
        || INSECURE_URI.matcher(uri).matches()) {
            return null;
        }
        // Convert to absolute path.
        return SystemPropertyUtil.get("user.dir") + File.separator + uri;
    }
    private static final Pattern ALLOWED_FILE_NAME = Pattern.compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");
    private static void sendListing(ChannelHandlerContext ctx, File dir) {
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK);
        response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
        StringBuilder buf = new StringBuilder();
        String dirPath = dir.getPath();
        buf.append("<!DOCTYPE html>\r\n");
        buf.append("<html><head><title>");
        buf.append("Listing of: ");
        buf.append(dirPath);
        buf.append("</title></head><body>\r\n");
        buf.append("Listing of: ");
        buf.append(dirPath);
        buf.append("\r\n");
        buf.append("");
        buf.append("..\r\n");
        for (File f : dir.listFiles()) {
            if (f.isHidden() || !f.canRead()) {
                continue;
            }
            String name = f.getName();
            if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
                continue;
            }
            buf.append("<a href=\"");
            buf.append(name);
            buf.append("\">");
            buf.append(name);
            buf.append("\r\n");
        }
        buf.append("</body></html>\r\n");
        ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8);
        response.content().writeBytes(buffer);
        buffer.release();
        // Close the connection as soon as the error message is sent.
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }
    private static void sendRedirect(ChannelHandlerContext ctx, String newUri) {
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, FOUND);
        response.headers().set(LOCATION, newUri);
        // Close the connection as soon as the error message is sent.
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }
    private static void sendError(ChannelHandlerContext ctx, HttpResponseStatus status) {
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, status, Unpooled.copiedBuffer("Failure: " + status + "\r\n", CharsetUtil.UTF_8));
        response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
        // Close the connection as soon as the error message is sent.
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }
    /**
    * When file timestamp is the same as what the browser is sending up, send a
    * "304 Not Modified"
    *
    * @param ctx
    * Context
    */
    private static void sendNotModified(ChannelHandlerContext ctx) {
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, NOT_MODIFIED);
        setDateHeader(response);
        // Close the connection as soon as the error message is sent.
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }
    /**
    * Sets the Date header for the HTTP response
    *
    * @param response
    * HTTP response
    */
    private static void setDateHeader(FullHttpResponse response) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
        dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
        Calendar time = new GregorianCalendar();
        response.headers().set(DATE, dateFormatter.format(time.getTime()));
    }
    /**
    * Sets the Date and Cache headers for the HTTP Response
    *
    * @param response
    * HTTP response
    * @param fileToCache
    * file to extract content type
    */
    private static void setDateAndCacheHeaders(HttpResponse response, File fileToCache) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
        dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
        // Date header
        Calendar time = new GregorianCalendar();
        response.headers().set(DATE, dateFormatter.format(time.getTime()));
        // Add cache headers
        time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
        response.headers().set(EXPIRES, dateFormatter.format(time.getTime()));
        response.headers().set(CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
        response.headers().set(LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified())));
    }
    /**
    * Sets the content type header for the HTTP Response
    *
    * @param response
    * HTTP response
    * @param file
    * file to extract content type
    */
    private static void setContentTypeHeader(HttpResponse response, File file) {
        MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
        response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
    }
}