6、netty http协议开发应用(netty学习笔记)

1、Netty http服务端入门

1.1http文件服务器。

package com.play.netty.http.fileserver;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;/*** 简单的基于HTTP的文件服务器* Created by IntelliJ IDEA.* User: GongQi* Date: 2017/9/25*/public class HttpFileServer {    private static final String DEFAULT_URL = "/src/main/java/com/play/netty/";    public void run(String host, Integer port, final String url) throws InterruptedException {        //启动2个线程组        final EventLoopGroup bossGrop = new NioEventLoopGroup();        EventLoopGroup workGrop = new NioEventLoopGroup();        try {            //启动器            ServerBootstrap bootstrap = new ServerBootstrap();            //绑定线组            bootstrap.group(bossGrop, workGrop)                    .channel(NioServerSocketChannel.class)                    .childHandler(new ChannelInitializer<SocketChannel>() {                        protected void initChannel(SocketChannel socketChannel) throws Exception {                            socketChannel.pipeline()                                    .addLast("http-decoder", new HttpRequestDecoder());                            //它的作用是将多个消息转换为单一的FullHttpRequest或者FullHttpResponse                            //http解码器在每个http消息体中会生成多个消息对象                            //(1)HttpRequest\HttpResponse                            //(2)HttpContent                            //(3)LastHttpContent                            socketChannel.pipeline()                                    .addLast("http-aggregator", new HttpObjectAggregator(65536));                            socketChannel.pipeline()                                    .addLast("http-encoder", new HttpResponseEncoder());                            //为了支持异步发送大码流，不占用过多内存防止内存溢出                            socketChannel.pipeline()                                    .addLast("http-chunked", new ChunkedWriteHandler());                            //我们需要的业务处理器                            socketChannel.pipeline()                                    .addLast("fileServerHander", new HttpFileServerHander(url));                        }                    });            //绑定端口            ChannelFuture channelFuture = bootstrap.bind(host, port).sync();            System.out.println("系统启动完毕........");            //同步等待            channelFuture.channel().closeFuture().sync();        } finally {            bossGrop.shutdownGracefully();            workGrop.shutdownGracefully();        }    }    public static void main(String[] args) throws InterruptedException {        Integer port = 8080;        String url = DEFAULT_URL;        new HttpFileServer().run("localhost", port, url);    }}

HttpFileServerHander.java

package com.play.netty.http.fileserver;import io.netty.buffer.ByteBuf;import io.netty.buffer.Unpooled;import io.netty.channel.*;import io.netty.handler.codec.http.*;import io.netty.handler.stream.ChunkedFile;import io.netty.util.CharsetUtil;import javax.activation.MimetypesFileTypeMap;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 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.HttpHeaders.isKeepAlive;import static io.netty.handler.codec.http.HttpHeaders.setContentLength;import static io.netty.handler.codec.http.HttpMethod.GET;import static io.netty.handler.codec.http.HttpResponseStatus.*;import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;/*** Created by IntelliJ IDEA.* User: GongQi* Date: 2017/9/25*/public class HttpFileServerHander extends SimpleChannelInboundHandler<FullHttpRequest> {    private final String url;    private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");    private static final Pattern ALLOWED_FILE_NAME = Pattern            .compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");    public HttpFileServerHander(String url) {        this.url = url;    }    public void messageReceived(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {        //如果解码失败则返回错误        if (!request.getDecoderResult().isSuccess()) {            sendError(ctx, BAD_REQUEST);            return;        }        //如果不是get则报错        if (request.getMethod() != GET) {            sendError(ctx, METHOD_NOT_ALLOWED);            return;        }        //获取uri并加工        final String uri = request.getUri();        final String path = sanitizeUri(uri);        if (path == null) {            sendError(ctx, FORBIDDEN);            return;        }        //        //获取文件        File file = new File(path);        if (file.isHidden() || !file.exists()) {            sendError(ctx, NOT_FOUND);            return;        }        //如果是目录则返回目录信息        if (file.isDirectory()) {            if (uri.endsWith("/")) {                sendListing(ctx, file);            } else {                sendRedirect(ctx, uri + "/");            }            return;        }        if(!file.isFile()){            sendError(ctx,FORBIDDEN);        }        RandomAccessFile randomAccessFile;        try {            randomAccessFile = new RandomAccessFile(file, "r");        } catch (FileNotFoundException e) {            sendError(ctx, NOT_FOUND);            return;        }        //获取文件的长度        long fileLength = randomAccessFile.length();        //构造HTTP应答消息，这边不能用FullHttpResponse，原因后续再说。        HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);        setContentLength(response, fileLength);        setContentTypeHeader(response, file);        //判断是否keep-alive        if (isKeepAlive(request)) {            response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE);        }        ctx.write(response);        //通过Netty的ChunkedFile将文件直接写入到发送缓冲区        ChannelFuture sendFileFeature;        sendFileFeature= ctx.write(new ChunkedFile(randomAccessFile, 0,                                fileLength, 8192), ctx.newProgressivePromise());        //添加GenericProgressiveFutureListener,如果发送完成打印 System.out.println("Transfer complete");        sendFileFeature.addListener(new ChannelProgressiveFutureListener() {            //            public void operationProgressed(ChannelProgressiveFuture future, long progress, long total) throws Exception {                if (total < 0) {                    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");            }        });        //发送一个EMPTY_LAST_CONTENT说明完成        ChannelFuture lastContentFuture = ctx                .writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);        if (!isKeepAlive(request)) {            lastContentFuture.addListener(ChannelFutureListener.CLOSE);        }    }    private void setContentTypeHeader(HttpResponse response, File file) {        MimetypesFileTypeMap mimetypesFileTypeMap = new MimetypesFileTypeMap();        response.headers().set(CONTENT_TYPE,                mimetypesFileTypeMap.getContentType(file.getPath()));    }    /**    * 构造错误信息    *    * @param ch    * @param status    */    private void sendError(ChannelHandlerContext ch, HttpResponseStatus status) {        FullHttpResponse response = new DefaultFullHttpResponse(                HTTP_1_1,                status,                Unpooled.copiedBuffer("Faile: " + status.toString() + "\r\n", CharsetUtil.UTF_8));        //        response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");        ch.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);    }    /**    * 加工url    * @param uri    * @return    */    private String sanitizeUri(String uri) {        //先用UTF-8解码，如果失败了在用ISO-8859-1        try {            uri = URLDecoder.decode(uri, "UTF-8");        } catch (UnsupportedEncodingException e) {            try {                uri = URLDecoder.decode(uri, "ISO-8859-1");            } catch (UnsupportedEncodingException e1) {                throw new Error();            }        }        //如果不是符合规范的请求，则拒绝        if (!uri.startsWith(url) || !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;    }    /**    * 构造显示的列表信息    * @param context    * @param dir    */    private void sendListing(ChannelHandlerContext context, File dir) {        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK);        //创建成功的http相应消息，使用text/html便于直接显示再浏览器上        response.headers().set(CONTENT_TYPE, "text/html;charset=UTF-8");        StringBuilder builder = new StringBuilder();        String dirPath = dir.getPath();        //拼接HTML        builder.append("<!DOCTYPE html>\r\n");        builder.append("<html><head><title>");        builder.append(dirPath);        builder.append("目录:");        builder.append("</title></head><body>\r\n");        builder.append("<h3>");        builder.append(dirPath).append(" 目录: ");        builder.append("</h3>\r\n");        builder.append("<ul>");        builder.append("<li>链接:<a href=\"../\">..</a></li>\r\n");        //构造列表        for (File file : dir.listFiles()) {            if (file.isHidden() || !file.canRead()) {                continue;            }            //过滤文件名            String fileName = file.getName();            if (!ALLOWED_FILE_NAME.matcher(fileName).matches()) {                continue;            }            //超链接            builder.append("<li>链接: <a href=\" ");            builder.append(fileName);            builder.append("\">");            builder.append(fileName);            builder.append("</a></li>\r\n");        }        builder.append("</ul></body></html>\r\n");        //万能的ByteBuf        ByteBuf byteBuf = Unpooled.copiedBuffer(builder, CharsetUtil.UTF_8);        response.content().writeBytes(byteBuf);        //释放缓存区        byteBuf.release();        context.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);    }    /**    * 从定向    *    * @param context    * @param newUri    */    private void sendRedirect(ChannelHandlerContext context, String newUri) {        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, FOUND);        response.headers().set(LOCATION, newUri);        context.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);    }    public void exceptionCaught(ChannelHandlerContext context,Throwable cause){        cause.printStackTrace();        if(context.channel().isActive()){            sendError(context,INTERNAL_SERVER_ERROR);        }    }}