netty搭建http服务器

public class HttpServerStart {
    public static volatile boolean flag = false ;
    public static void start() {
        int port = 8099;
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new HttpServerInitializer())
                    .option(ChannelOption.SO_BACKLOG, 1024)
                    .childOption(ChannelOption.SO_KEEPALIVE, true);

            Channel ch = b.bind(port).sync().channel();
            System.out.println("httpserver服务成功启动,请打开 http://127.0.0.1:" + port);
            flag = true ;
            ch.closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

public class HttpServerInitializer  extends ChannelInitializer<SocketChannel> {
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        //HttpObjectAggregator HTTP 消息解码器， 作用时将多个消息转换为1个FullHttpRequest 或者 FullHttpResponse 对象
        /**
         * HttpRequestDecoder 会将每个 HTTP 消息转换为 多个消息对象
         * HttpResquest / HttpResponse
         * HttpContent
         * LastHttpContent
         */
        //将请求和应答消息编码或解码为HTTP消息
        socketChannel.pipeline().addLast(new HttpRequestDecoder());
        socketChannel.pipeline().addLast(new HttpObjectAggregator(65536));// 目的是将多个消息转换为单一的request或者response对象
        socketChannel.pipeline().addLast(new HttpResponseEncoder());
        socketChannel.pipeline().addLast(new ChunkedWriteHandler());//目的是支持异步大文件传输（）
        socketChannel.pipeline().addLast("file-handler", new FileServerHandler());
        socketChannel.pipeline().addLast("handler", new HttpServerHandler(false));
    }
}

public class HttpServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }


    public HttpServerHandler(boolean isAutoRelease){
        super(isAutoRelease);
    }


    protected void channelRead0(ChannelHandlerContext channelHandlerContext, FullHttpRequest request) throws Exception {
        try {
            if(!request.decoderResult().isSuccess()){
                DonkeyHttpUtil.writeResponse(request, BAD_REQUEST, channelHandlerContext);
                return;
            }
            if(request.method() != HttpMethod.GET){
                DonkeyHttpUtil.writeResponse(request, METHOD_NOT_ALLOWED, channelHandlerContext);
                return;
            }
            DonkeyHttpUtil.writeResponse(request, OK, channelHandlerContext);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }



    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}

public class FileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {



    protected void channelRead0(ChannelHandlerContext channelHandlerContext, FullHttpRequest request) throws Exception {
        //request.retain();
        HttpResponse response = null;
        RandomAccessFile randomAccessFile = null;
        try{
            // 状态为1xx的话，继续请求
            if (HttpHeaders.is100ContinueExpected(request)) {
                send100Continue(channelHandlerContext);
            }
            String uri = request.uri();//   /digitalPlatform/common/common.js
            if(!uri.endsWith(".js")
                    && !uri.endsWith(".css")
                    && !uri.endsWith(".html")
                    && !uri.endsWith(".png")
                    && !uri.endsWith(".jpg")
                    && !uri.endsWith(".gif")){
                channelHandlerContext.fireChannelRead(request);
                return;
            }
            uri = uri.substring(1);
            InputStream input = MyApplication.getApplication().getAssets().open(uri);
            File f = new File
                    (Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "cloudsapp"+File.separator+uri);

            if (f.exists()) {
                f.delete();
            }else{
                f.getParentFile().mkdirs();
            }
            f.createNewFile();
            byte[] bytes = new byte[input.available()];
            input.read(bytes);

            OutputStream os = new FileOutputStream(f);
            BufferedOutputStream bos = new BufferedOutputStream(os);
            bos.write(bytes);
            bos.flush();
            bos.close();

           try {
                randomAccessFile = new RandomAccessFile(f, "r");
            } catch (FileNotFoundException e) {
                DonkeyHttpUtil.writeResponse(request, NOT_FOUND, channelHandlerContext);
                e.printStackTrace();
                return;
            }

            if(!f.exists() || f.isHidden()){
                DonkeyHttpUtil.writeResponse(request, NOT_FOUND, channelHandlerContext);
                return;
            }
            long fileLength = randomAccessFile.length();
            response = new DefaultHttpResponse(request.protocolVersion(), HttpResponseStatus.OK);

            setContentType(response, f);
            boolean keepAlive =  HttpUtil.isKeepAlive(request);
            if (keepAlive) {
                response.headers().set(HttpHeaderNames.CONTENT_LENGTH, fileLength);
                response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
            }
            channelHandlerContext.write(response);


            ChannelFuture sendFileFuture = channelHandlerContext.write(new ChunkedNioFile(randomAccessFile.getChannel()), channelHandlerContext.newProgressivePromise());
            // 写入文件尾部
            sendFileFuture.addListener(new ChannelProgressiveFutureListener() {
                @Override
                public void operationProgressed(ChannelProgressiveFuture future,
                                                long progress, long total) {
                    if (total < 0) { // total unknown
                        System.out.println("Transfer progress: " + progress);
                    } else {
                        System.out.println("Transfer progress: " + progress + " / "
                                + total);
                    }
                }

                @Override
                public void operationComplete(ChannelProgressiveFuture future)
                        throws Exception {
                    System.out.println("Transfer complete.");
                }


            });
            ChannelFuture lastContentFuture =  channelHandlerContext.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
            if (!keepAlive) {
                lastContentFuture.addListener(ChannelFutureListener.CLOSE);
            }
        }catch (Exception e){
            DonkeyHttpUtil.writeResponse(request, NOT_FOUND, channelHandlerContext);
            e.printStackTrace();
        }finally {
            if(randomAccessFile != null){
                try {
                    randomAccessFile.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }else{
                DonkeyHttpUtil.writeResponse(request, NOT_FOUND, channelHandlerContext);
            }
        }
    }


    public static void writeBytesToFile(InputStream is, File file) throws IOException{
        FileOutputStream fos = null;
        try {
            byte[] data = new byte[2048];
            int nbread = 0;
            fos = new FileOutputStream(file);
            while((nbread=is.read(data))>-1){
                fos.write(data,0,nbread);
            }
        }
        catch (Exception ex) {
            Log.e("Exception",ex.getMessage());
        }
        finally{
            if (fos!=null){
                fos.close();
            }
        }
    }
    private void setContentType(HttpResponse response, File file){
        //MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
        if(file.getName().endsWith(".js")){
            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "application/x-javascript");
        }else if(file.getName().endsWith(".css")){
            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/css; charset=UTF-8");
        }else if (file.getName().endsWith(".html")){
            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=UTF-8");
        }
    }
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }

    private static void send100Continue(ChannelHandlerContext ctx) {
        FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE);
        ctx.writeAndFlush(response);
    }
}

public class DonkeyHttpUtil {


    public static boolean writeResponse(FullHttpRequest request, HttpResponseStatus status, ChannelHandlerContext ctx) {
        // Decide whether to close the connection or not.
        boolean keepAlive = HttpUtil.isKeepAlive(request);
        // Build the response object.
        FullHttpResponse response = new DefaultFullHttpResponse(request.protocolVersion(), status,
                Unpooled.copiedBuffer(status.toString(), CharsetUtil.UTF_8));
        response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain; charset=UTF-8");
        if (keepAlive) {
            // Add ‘Content-Length‘ header only for a keep-alive connection.
            response.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
            // Add keep alive header as per:
            response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
        }

        // Encode the cookie.
        String cookieString = request.headers().get(HttpHeaderNames.COOKIE);
        if (cookieString != null) {
            Set<io.netty.handler.codec.http.cookie.Cookie> cookies = ServerCookieDecoder.STRICT.decode(cookieString);
            if (!cookies.isEmpty()) {
                // Reset the cookies if necessary.
                for (io.netty.handler.codec.http.cookie.Cookie cookie : cookies) {
                    response.headers().add(HttpHeaderNames.SET_COOKIE, ServerCookieEncoder.STRICT.encode(cookie));
                }
            }
        }
        // Write the response.
        ctx.write(response);
        return keepAlive;
    }
}