通过学习搭建一个简单的文件服务器，使用http协议对外提供服务，当客户端通过浏览器访问文件服务器时，对访问路径进行检查，检查失败时返回403错误，该页无法访问，如果校验通过，以链接的方式打开当前文件目录，每个目录下是超链接，可以递归访问，如果是文件则下载。
代码实现
package com.dpb.netty.http; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelInitializer; 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.HttpRequestDecoder; import io.netty.handler.codec.http.HttpResponseEncoder; import io.netty.handler.stream.ChunkedWriteHandler; public class HttpFileServer { private static final String DEFAULT_URL = "/src/main/java/com/dpb/netty/"; public void run(final int port, final String url) throws Exception { EventLoopGroup bossGroup = new NioEventLoopGroup(); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class) .childHandler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) throws Exception { // 添加请求消息解码器 ch.pipeline().addLast("http-decoder", new HttpRequestDecoder()); //HttpObjectAggregator的作用 将多个消息转换为单一的FullHttpRequest或者FullHttpResponse ch.pipeline().addLast("http-aggregator", new HttpObjectAggregator(65536)); // 添加响应解码器 ch.pipeline().addLast("http-encoder", new HttpResponseEncoder()); // 支持异步发送大的码流(大的文件传输),但不占用过多的内存，防止java内存溢出 ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler()); // 添加自定义handler 处理文件服务器业务逻辑 ch.pipeline().addLast("fileServerHandler", new HttpFileServerHandler(url)); } }); ChannelFuture future = b.bind("127.0.0.1", port).sync(); System.out.println("HTTP文件目录服务器启动，网址是 : " + "http://127.0.0.1:" + port + url); future.channel().closeFuture().sync(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } public static void main(String[] args) throws Exception { int port = 8080; if (args.length > 0) { try { port = Integer.parseInt(args[0]); } catch (NumberFormatException e) { e.printStackTrace(); } } String url = DEFAULT_URL; if (args.length > 1) url = args[1]; new HttpFileServer().run(port, url); } }
HttpFileServerHandler
package com.dpb.netty.http; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpHeaders.setContentLength; import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION; import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE; import static io.netty.handler.codec.http.HttpHeaders.Names.LOCATION; import static io.netty.handler.codec.http.HttpMethod.GET; 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.METHOD_NOT_ALLOWED; import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND; import static io.netty.handler.codec.http.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import java.io.File; import java.io.FileNotFoundException; import java.io.RandomAccessFile; import java.io.UnsupportedEncodingException; import java.net.URLDecoder; import java.util.regex.Pattern; import javax.activation.MimetypesFileTypeMap; 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.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.HttpHeaders; import io.netty.handler.codec.http.HttpResponse; import io.netty.handler.codec.http.HttpResponseStatus; import io.netty.handler.codec.http.LastHttpContent; import io.netty.handler.stream.ChunkedFile; import io.netty.util.CharsetUtil; public class HttpFileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> { private final String url; public HttpFileServerHandler(String url) { this.url = url; } @Override public void messageReceived(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception { // 解码失败 400 if (!request.getDecoderResult().isSuccess()) { sendError(ctx, BAD_REQUEST); return; } // 只支持get方法 if (request.getMethod() != GET) { sendError(ctx, METHOD_NOT_ALLOWED); return; } // final String uri = request.getUri(); // 处理Uri地址 final String path = sanitizeUri(uri); if (path == null) { sendError(ctx, FORBIDDEN); return; } File file = new File(path); // 如果文件不存在，或不可访问 if (file.isHidden() || !file.exists()) { sendError(ctx, NOT_FOUND); return; } // 如果请求是文件夹 if (file.isDirectory()) { // 请求以 '/'结尾，列出该文件夹下的所有内容 if (uri.endsWith("/")) { sendListing(ctx, file); } else { // 否则自动补全'/' 然后再重定向访问 sendRedirect(ctx, uri + '/'); } return; } if (!file.isFile()) { sendError(ctx, FORBIDDEN); return; } RandomAccessFile randomAccessFile = null; try { randomAccessFile = new RandomAccessFile(file, "r");// 以只读的方式打开文件 } catch (FileNotFoundException fnfe) { sendError(ctx, NOT_FOUND); return; } long fileLength = randomAccessFile.length(); // 创建一个默认的Http响应 HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK); // 设置响应文件大小 setContentLength(response, fileLength); // 设置 content Type setContentTypeHeader(response, file); // 设置 keep alive if (isKeepAlive(request)) { response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE); } ctx.write(response); ChannelFuture sendFileFuture; //通过Netty的ChunkedFile对象直接将文件写入发送到缓冲区中 sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 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("Transfer progress: " + progress); } else { System.err.println("Transfer progress: " + progress + " / " + total); } } @Override public void operationComplete(ChannelProgressiveFuture future) throws Exception { System.out.println("Transfer complete."); } }); ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT); //如果不支持keep-Alive，服务器端主动关闭请求 if (!isKeepAlive(request)) { lastContentFuture.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); if (ctx.channel().isActive()) { sendError(ctx, INTERNAL_SERVER_ERROR); } } private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*"); /** * 格式化uri并且获取路径 * @param uri * @return */ private String sanitizeUri(String uri) { try { uri = URLDecoder.decode(uri, "UTF-8"); } catch (UnsupportedEncodingException e) { try { uri = URLDecoder.decode(uri, "ISO-8859-1"); } catch (UnsupportedEncodingException e1) { throw new Error(); } } if (!uri.startsWith(url)) { return null; } if (!uri.startsWith("/")) { return null; } uri = uri.replace('/', File.separatorChar); if (uri.contains(File.separator + '.') || uri.contains('.' + File.separator) || uri.startsWith(".") || uri.endsWith(".") || INSECURE_URI.matcher(uri).matches()) { return null; } return System.getProperty("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(dirPath); buf.append(" 目录："); buf.append("</title></head><body>\r\n"); buf.append("<h3>"); buf.append(dirPath).append(" 目录："); buf.append("</h3>\r\n"); buf.append("<ul>"); buf.append("<li>链接：<a href=\"../\">..</a></li>\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("<li>链接：<a href=\""); buf.append(name); buf.append("\">"); buf.append(name); buf.append("</a></li>\r\n"); } buf.append("</ul></body></html>\r\n"); ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8); response.content().writeBytes(buffer); buffer.release(); 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); 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.toString() + "\r\n", CharsetUtil.UTF_8)); response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8"); ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE); } private static void setContentTypeHeader(HttpResponse response, File file) { MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap(); response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath())); } }
测试效果
地址输出错的请求
访问成功
搭建很简单，可以跑下代码，关键多推敲下代码~
