Netty之二进制文件传输

传输会话简要

客户端发起一个文本请求给服务器端, 服务器端解析里面文本, 返回文件给客户端, 客户端解析文件

服务器端

因为示例文件比较小, 所以没有做分段传输, 而是直接一次性把整个文件byte[]都发给客户端了.

如果需要传输大文件, 则需要做粘包拆包, 参考另外一篇博文 Netty之粘包分包

需要三个ChannelPipeline

                             // 解析客户端发送的文本json
                             pipeline.addLast(new StringDecoder());
                             // 二进制文件加密传输
                             pipeline.addLast(new ObjectEncoder());
                             // 业务逻辑
                             pipeline.addLast(new FileServerHandler());

FileServerHandler业务逻辑

            // 获取到客户端请求, 解析path, 返回二进制文件
            JSONObject jo = new JSONObject(msg.toString());
            if (StringUtils.isNotEmpty(jo.optString("path"))) {
                PDFContent pdf = new PDFContent();
                byte[] content = com.fr.general.IOUtils.inputStream2Bytes(new FileInputStream(jo.optString("path")));
                pdf.setContent(content);
                ctx.writeAndFlush(pdf);
            } else {
                System.out.println(jo.optString("res"));
            }

客户端

跟服务器端对应的三个ChannelPipeline

                             // 传输文本给服务器端
                             p.addLast(new StringEncoder());
                             // 二进制文件获取解析
                             p.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(this
                                     .getClass().getClassLoader())));
                             // 客户端业务代码
                             p.addLast(new FileClientHandler());

FileClientHandler业务逻辑

         @Override
         public void channelActive(ChannelHandlerContext ctx) {
             try {
                 // 将要获取的pdf路径发送给服务器端
                 JSONObject jo = JSONObject.create().put("path", "d:\\a.pdf");
                 ctx.writeAndFlush(jo.toString());
             } catch (JSONException e) {
                 e.printStackTrace();
             }
         }

         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) {
             PDFContent content = (PDFContent) msg;
             // 从服务器端获取的二进制文件存到本地
             String fileName = UUID.randomUUID().toString() + ".pdf";
             File file = new File("D:\\" + fileName);
             try {
                 FileOutputStream out = new FileOutputStream(file);
                 IOUtils.copyBinaryTo(new ByteArrayInputStream(content.getContent()), out);
                 out.close();
             } catch (FileNotFoundException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }
             try {
                 JSONObject jo = JSONObject.create().put("res", "Thank You, I Have The File!");
                 ctx.writeAndFlush(jo.toString());
                 ctx.close();
             } catch (JSONException e) {
                 e.printStackTrace();
             }
         }

完整的代码如下

FileClient & FileClientHandler

 package test;

 import com.fr.general.IOUtils;
 import com.fr.json.JSONException;
 import com.fr.json.JSONObject;
 import com.fr.stable.core.UUID;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 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.NioSocketChannel;
 import io.netty.handler.codec.serialization.ClassResolvers;
 import io.netty.handler.codec.serialization.ObjectDecoder;
 import io.netty.handler.codec.string.StringEncoder;

 import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;

 public class FileClient {

     public FileClient(){

     }

     public void start() {
         EventLoopGroup group = new NioEventLoopGroup();
         try {
             Bootstrap bootstrap = new Bootstrap();
             bootstrap.group(group)
                     .channel(NioSocketChannel.class)
                     .handler(new ChannelInitializer<SocketChannel>() {

                         @Override
                         protected void initChannel(SocketChannel s) throws Exception {
                             ChannelPipeline p = s.pipeline();
                             // 传输文本给服务器端
                             p.addLast(new StringEncoder());
                             // 二进制文件获取解析
                             p.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(this
                                     .getClass().getClassLoader())));
                             // 客户端业务代码
                             p.addLast(new FileClientHandler());
                         }
                     });
             ChannelFuture future = bootstrap.connect("localhost", 7766).sync();
             future.channel().closeFuture().sync();
         } catch (InterruptedException e) {
             e.printStackTrace();
         } finally {
             group.shutdownGracefully();
         }
     }

     public static void main(String[] args) throws InterruptedException {
         new FileClient().start();
     }

     private static class FileClientHandler extends ChannelInboundHandlerAdapter {

         @Override
         public void channelActive(ChannelHandlerContext ctx) {
             try {
                 // 将要获取的pdf路径发送给服务器端
                 JSONObject jo = JSONObject.create().put("path", "d:\\a.pdf");
                 ctx.writeAndFlush(jo.toString());
             } catch (JSONException e) {
                 e.printStackTrace();
             }
         }

         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) {
             PDFContent content = (PDFContent) msg;
             // 从服务器端获取的二进制文件存到本地
             String fileName = UUID.randomUUID().toString() + ".pdf";
             File file = new File("D:\\" + fileName);
             try {
                 FileOutputStream out = new FileOutputStream(file);
                 IOUtils.copyBinaryTo(new ByteArrayInputStream(content.getContent()), out);
                 out.close();
             } catch (FileNotFoundException e) {
                 e.printStackTrace();
             } catch (IOException e) {
                 e.printStackTrace();
             }
             try {
                 JSONObject jo = JSONObject.create().put("res", "Thank You, I Have The File!");
                 ctx.writeAndFlush(jo.toString());
                 ctx.close();
             } catch (JSONException e) {
                 e.printStackTrace();
             }
         }

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

FileServer & FileServerHandler

 package test;

 import com.fr.json.JSONObject;
 import com.fr.stable.StringUtils;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 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.serialization.ObjectEncoder;
 import io.netty.handler.codec.string.StringDecoder;
 import io.netty.handler.logging.LogLevel;
 import io.netty.handler.logging.LoggingHandler;

 import java.io.FileInputStream;

 public class FileServer {

     private FileServer() {
         startServer();
     }

     private void startServer() {
         EventLoopGroup bossGroup = new NioEventLoopGroup(1);
         EventLoopGroup workerGroup = new NioEventLoopGroup();
         try{
             ServerBootstrap bootstrap = new ServerBootstrap();
             bootstrap.group(bossGroup, workerGroup)
                     .channel(NioServerSocketChannel.class)
                     .option(ChannelOption.SO_BACKLOG, 100)
                     .handler(new LoggingHandler(LogLevel.INFO))
                     .childHandler(new ChannelInitializer<SocketChannel>() {
                         @Override
                         protected void initChannel(SocketChannel ch) throws Exception {
                             ChannelPipeline pipeline = ch.pipeline();
                             // 解析客户端发送的文本json
                             pipeline.addLast(new StringDecoder());
                             // 二进制文件加密传输
                             pipeline.addLast(new ObjectEncoder());
                             // 业务逻辑
                             pipeline.addLast(new FileServerHandler());
                         }
                     });
             ChannelFuture future = bootstrap.bind("localhost", 7766).sync();
             future.channel().closeFuture().sync();
         } catch (InterruptedException e) {
             e.printStackTrace();
         } finally {
             bossGroup.shutdownGracefully();
             workerGroup.shutdownGracefully();
         }

     }

     private class FileServerHandler extends ChannelInboundHandlerAdapter {

         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
             // 获取到客户端请求, 解析path, 返回二进制文件
             JSONObject jo = new JSONObject(msg.toString());
             if (StringUtils.isNotEmpty(jo.optString("path"))) {
                 PDFContent pdf = new PDFContent();
                 byte[] content = com.fr.general.IOUtils.inputStream2Bytes(new FileInputStream(jo.optString("path")));
                 pdf.setContent(content);
                 ctx.writeAndFlush(pdf);
             } else {
                 System.out.println(jo.optString("res"));
             }
         }

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

     public static void main(String[] args){
         // 启动Server
         new FileServer();
     }

 }

PDFContent

 package test;

 import java.io.Serializable;

 /**
  * 文件的封装
  */
 public class PDFContent implements Serializable{

     private byte[] content;

     public byte[] getContent() {
         return content;
     }

     public void setContent(byte[] content) {
         this.content = content;
     }
 }