Netty HTTP 文件下载例子

一样不废话，上代码

一定要记得在代码的同级别目录建立一个sources目录，里面存放需要下载的测试文件

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import static io.netty.handler.codec.http.HttpHeaderNames.*;
import static io.netty.handler.codec.http.HttpMethod.*;
import static io.netty.handler.codec.http.HttpResponseStatus.*;
import static io.netty.handler.codec.http.HttpVersion.*;
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.HttpHeaderUtil;
import io.netty.handler.codec.http.HttpHeaderValues;
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 {
        //对请求的解码结果进行判断：
        if (!request.decoderResult().isSuccess()) {
            // 400
            sendError(ctx, BAD_REQUEST);
            return;
        }
        //对请求方式进行判断：如果不是get方式（如post方式）则返回异常
        if (request.method() != GET) {
            // 405
            sendError(ctx, METHOD_NOT_ALLOWED);
            return;
        }
        //获取请求uri路径
        final String uri = request.uri();
        //对url进行分析，返回本地系统
        final String path = sanitizeUri(uri);
        //如果 路径构造不合法，则path为null
        if (path == null) {
            //403
            sendError(ctx, FORBIDDEN);
            return;
        }
        // 创建file对象
        File file = new File(path);
        // 判断文件是否为隐藏或者不存在
        if (file.isHidden() || !file.exists()) {
            // 404 
            sendError(ctx, NOT_FOUND);
            return;
        }
        // 如果为文件夹
        if (file.isDirectory()) {
            if (uri.endsWith("/")) {
                //如果以正常"/"结束 说明是访问的一个文件目录：则进行展示文件列表（web服务端则可以跳转一个Controller，遍历文件并跳转到一个页面）
                sendListing(ctx, file);
            } else {
                //如果非"/"结束 则重定向，补全"/" 再次请求
                sendRedirect(ctx, uri + '/');
            }
            return;
        }
        // 如果所创建的file对象不是文件类型
        if (!file.isFile()) {
            // 403
            sendError(ctx, FORBIDDEN);
            return;
        }

        //随机文件读写类
        RandomAccessFile randomAccessFile = null;
        try {
            randomAccessFile = new RandomAccessFile(file, "r");// 以只读的方式打开文件
        } catch (FileNotFoundException fnfe) {
            // 404
            sendError(ctx, NOT_FOUND);
            return;
        }

        //获取文件长度
        long fileLength = randomAccessFile.length();
        //建立响应对象
        HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
        //设置响应信息
        HttpHeaderUtil.setContentLength(response, fileLength);
        //设置响应头
        setContentTypeHeader(response, file);
        //如果一直保持连接则设置响应头信息为：HttpHeaders.Values.KEEP_ALIVE
        if (HttpHeaderUtil.isKeepAlive(request)) {
            response.headers().set(CONNECTION, HttpHeaderValues.KEEP_ALIVE);
        }
        //进行写出
        ctx.write(response);

        //构造发送文件线程，将文件写入到Chunked缓冲区中
        ChannelFuture sendFileFuture;
        //写出ChunkedFile
        sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 0, fileLength, 8192), ctx.newProgressivePromise());
        //添加传输监听
        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.");
            }
        });

        //如果使用Chunked编码，最后则需要发送一个编码结束的看空消息体，进行标记，表示所有消息体已经成功发送完成。
        ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
        //如果当前连接请求非Keep-Alive ，最后一包消息发送完成后 服务器主动关闭连接
        if (!HttpHeaderUtil.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);
            ctx.close();
        }
    }

    //非法URI正则
    private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");

    /**
     * 方法名称：解析URI

     * 概要说明：对URI进行分析

     * @param uri netty包装后的字符串对象
     * @return path 解析结果
     */
    private String sanitizeUri(String uri) {
        try {
            //使用UTF-8字符集
            uri = URLDecoder.decode(uri, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            try {
                //尝试ISO-8859-1
                uri = URLDecoder.decode(uri, "ISO-8859-1");
            } catch (UnsupportedEncodingException e1) {
                //抛出预想外异常信息
                throw new Error();
            }
        }
        // 对uri进行细粒度判断：4步验证操作
        // step 1 基础验证
        if (!uri.startsWith(url)) {
            return null;
        }
        // step 2 基础验证
        if (!uri.startsWith("/")) {
            return null;
        }
        // step 3 将文件分隔符替换为本地操作系统的文件路径分隔符
        uri = uri.replace('/', File.separatorChar);
        // step 4 二次验证合法性
        if (uri.contains(File.separator + '.')
            || uri.contains('.' + File.separator) || uri.startsWith(".")
            || uri.endsWith(".") || INSECURE_URI.matcher(uri).matches()) {
            return null;
        }
        //当前工程所在目录 + URI构造绝对路径进行返回 
        return System.getProperty("user.dir") + File.separator + uri;
    }

    //文件是否被允许访问下载验证
    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) {
        // 设置响应对象
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK);
        // 响应头
        response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
        // 追加文本内容
        StringBuilder ret = new StringBuilder();
        String dirPath = dir.getPath();
        ret.append("\r\n");
        ret.append("\r\n");
        ret.append("
");
        ret.append(dirPath).append(" 目录：");
        ret.append("
\r\n");
        ret.append("
");
        ret.append("
链接：..
\r\n");

        // 遍历文件 添加超链接
        for (File f : dir.listFiles()) {
            //step 1: 跳过隐藏或不可读文件 
            if (f.isHidden() || !f.canRead()) {
                continue;
            }
            String name = f.getName();
            //step 2: 如果不被允许，则跳过此文件
            if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
                continue;
            }
            //拼接超链接即可
            ret.append("
链接：);
            ret.append(name);
            ret.append("\">");
            ret.append(name);
            ret.append("
\r\n");
        }
        ret.append("
\r\n");
        //构造结构，写入缓冲区
        ByteBuf buffer = Unpooled.copiedBuffer(ret, CharsetUtil.UTF_8);
        //进行写出操作
        response.content().writeBytes(buffer);
        //重置写出区域
        buffer.release();
        //使用ctx对象写出并且刷新到SocketChannel中去 并主动关闭连接(这里是指关闭处理发送数据的线程连接)
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }

    //重定向操作
    private static void sendRedirect(ChannelHandlerContext ctx, String newUri) {
        //建立响应对象
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, FOUND);
        //设置新的请求地址放入响应对象中去
        response.headers().set(LOCATION, newUri);
        //使用ctx对象写出并且刷新到SocketChannel中去 并主动关闭连接(这里是指关闭处理发送数据的线程连接)
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }

    //错误信息
    private static void sendError(ChannelHandlerContext ctx, HttpResponseStatus status) {
        //建立响应对象
        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, status, Unpooled.copiedBuffer("Failure: " + status.toString()+ "\r\n", CharsetUtil.UTF_8));
        //设置响应头信息
        response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
        //使用ctx对象写出并且刷新到SocketChannel中去 并主动关闭连接(这里是指关闭处理发送数据的线程连接)
        ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
    }

    private static void setContentTypeHeader(HttpResponse response, File file) {
        //使用mime对象获取文件类型
        MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
        response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
    }
}

---

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 = "/sources/";

    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() {
                @Override
                protected void initChannel(SocketChannel ch)
                    throws Exception {
                    // 加入http的解码器
                    ch.pipeline().addLast("http-decoder", new HttpRequestDecoder());
                    // 加入ObjectAggregator解码器，作用是他会把多个消息转换为单一的FullHttpRequest或者FullHttpResponse
                    ch.pipeline().addLast("http-aggregator", new HttpObjectAggregator(65536));
                    // 加入http的编码器
                    ch.pipeline().addLast("http-encoder", new HttpResponseEncoder());
                    // 加入chunked 主要作用是支持异步发送的码流（大文件传输），但不专用过多的内存，防止java内存溢出
                    ch.pipeline().addLast("http-chunked", new ChunkedWriteHandler());
                    // 加入自定义处理文件服务器的业务逻辑handler
                    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 = 8765;
        String url = DEFAULT_URL;
        new HttpFileServer().run(port, url);
    }
}

---

import java.io.File;
import java.io.FileOutputStream;
import java.util.HashMap;
import java.util.Map;

import bhz.utils.HttpCallerUtils;
import bhz.utils.HttpProxy;

public class Test {


    public static void main(String[] args) throws Exception{
        Map params = new HashMap();
        byte[] ret = HttpCallerUtils.getStream("http://192.168.1.111:8765/images/a.doc", params);

        //byte[] ret = HttpProxy.get("http://192.168.1.111:8765/images/006.jpg");
        //写出文件
        String writePath = System.getProperty("user.dir") + File.separatorChar + "receive" +  File.separatorChar + "a.doc";
        FileOutputStream fos = new FileOutputStream(writePath);
        fos.write(ret);
        fos.close();    


    }
}