Netty实现简单HTTP服务器
netty
package com.dxz.nettydemo.http; import java.io.UnsupportedEncodingException; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpRequest; import io.netty.handler.codec.http.HttpResponseStatus; import io.netty.handler.codec.http.HttpVersion; import io.netty.handler.codec.http.QueryStringDecoder; class HttpServerHandler extends ChannelInboundHandlerAdapter { @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws UnsupportedEncodingException { if (msg instanceof HttpRequest) { // 请求，解码器将请求转换成HttpRequest对象 HttpRequest request = (HttpRequest) msg; // 获取请求参数 QueryStringDecoder queryStringDecoder = new QueryStringDecoder(request.getUri()); String name = "World"; if (queryStringDecoder.parameters().get("name") != null) { name = queryStringDecoder.parameters().get("name").get(0); } // 响应HTML String responseHtml = "<html><body>Hello, " + name + "</body></html>"; byte[] responseBytes = responseHtml.getBytes("UTF-8"); int contentLength = responseBytes.length; // 构造FullHttpResponse对象，FullHttpResponse包含message body FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, Unpooled.wrappedBuffer(responseBytes)); response.headers().set("Content-Type", "text/html; charset=utf-8"); response.headers().set("Content-Length", Integer.toString(contentLength)); ctx.writeAndFlush(response); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } }
主类：
package com.dxz.nettydemo.http; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; 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.HttpServerCodec; public class HttpServer { public static void main(String[] args) throws InterruptedException { 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 public void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast(new HttpServerCodec()); pipeline.addLast(new HttpServerHandler()); } }); ChannelFuture f = b.bind(8080).sync(); f.channel().closeFuture().sync(); } finally { workerGroup.shutdownGracefully(); bossGroup.shutdownGracefully(); } } }
测试：
用浏览器访问：http://localhost:8080/
netty构建的文件服务器
1、首先加入的是HTTP请求消息解码器
ch.pipeline().addLast("http-decoder", new HttpRequestDecoder());
2、第2添加HttpObjectAggregator解密器，其作用是将多个消息转换为单一的FullHttpRequest或者FullHttpResponse，原因是HTTP解码器在每个HTTP消息中会生成多个消息对象：有1、HttpRequest/HttpResponse;2、HttpContent；3、LastHttpContent；
ch.pipeline().addLast("http-aggregator", new HttpObjectAggregator(65536));
3、第3增加HTTP响应编码器，对HTTP响应信息进行编码
ch.pipeline().addLast("http-encoder", new HttpResponseEncoder());
4、第4Chunked handler的主要作用是支持异步发送大的码流（例如大的文件传输），但不占用过多的内存，防止发生JAVA内存溢出错误
ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler());
5、第5HttpFileServerHandler用于文件服务器的业务逻辑处理
package com.dxz.nettydemo.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/dxz/nettydemo/http"; 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 { //首先加入的是HTTP请求消息解码器 ch.pipeline().addLast("http-decoder", new HttpRequestDecoder()); //第2添加HttpObjectAggregator解密器，其作用是将多个消息转换为单一的FullHttpRequest或者FullHttpResponse， //原因是HTTP解码器在每个HTTP消息中会生成多个消息对象：有1、HttpRequest/HttpResponse;2、HttpContent；3、LastHttpContent； ch.pipeline().addLast("http-aggregator", new HttpObjectAggregator(65536)); //第3增加HTTP响应编码器，对HTTP响应信息进行编码 ch.pipeline().addLast("http-encoder", new HttpResponseEncoder()); //第4Chunked handler的主要作用是支持异步发送大的码流（例如大的文件传输），但不占用过多的内存，防止发生JAVA内存溢出错误 ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler()); //第5HttpFileServerHandler用于文件服务器的业务逻辑处理 ch.pipeline().addLast("fileServerHandler", new HttpFileServerHandler(url)); } }); ChannelFuture future = b.bind("localhost", port).sync(); System.out.println("HTTP文件目录服务器启动，网址是 : " + "http://localhost:" + 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); } }
文件读取下载
package com.dxz.nettydemo.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 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; 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; 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 { //http请求消息解码结果的判断，如果解码失败，直接返回构造HTTP400 错误返回 if (!request.getDecoderResult().isSuccess()) { sendError(ctx, BAD_REQUEST); return; } if (request.getMethod() != GET) { sendError(ctx, METHOD_NOT_ALLOWED); return; } final String uri = request.getUri(); final String path = sanitizeUri(uri); if (path == null) { sendError(ctx, FORBIDDEN); return; } 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; } 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; } //待下载文件的长度 long fileLength = randomAccessFile.length(); HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK); setContentLength(response, fileLength); setContentTypeHeader(response, file); if (isKeepAlive(request)) { response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE); } ctx.write(response); ChannelFuture sendFileFuture; //通过netty的ChunkedFile对象将文件写入到发送缓冲区 sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 0, fileLength, 8192), ctx.newProgressivePromise()); sendFileFuture.addListener(new ChannelProgressiveFutureListener() { 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); } } public void operationComplete(ChannelProgressiveFuture future) throws Exception { System.out.println("Transfer complete."); } }); //使用chunked编码，最后需要发送一个编码结束 的空消息体，将LastHttpContent的EMPTY_LAST_CONTENT发送到缓冲区中，标识所有的消息体已经发送完成，同时 //用flush方法将之前在发送缓冲区的消息刷新到SocketChannel中发送给对方 ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT); //如果不是keep-alive，服务端在发送完成之后，服务端主动关闭连接 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(".*[<>&\"].*"); /** * 请求路径的处理 * @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) { //创建成功的HTTP响应消息 FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK); //设置消息头类型 response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8"); //构造响应消息体 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"); //分配对应消息的缓冲对象 ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8); //将缓冲区中的响应消息存放到HTTP应答消息中 response.content().writeBytes(buffer); //释放缓冲区 buffer.release(); //将响应消息刷新到SocketChannel中 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())); } }
演示：
