Netty TCP粘包/拆包问题《二》

1.DelimiterBasedFrameDecoder：是以分隔符作为结束标志进行解决粘包/拆包问题

代码：

　EchoClient：客户端

　　

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package nettyTcp01.echo;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
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.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class EchoClient {

    public void connect(int port, String host) throws Exception {
        // 配置客户端NIO线程组
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group).channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
                            ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));
                            ch.pipeline().addLast(new StringDecoder());
                            ch.pipeline().addLast(new EchoClientHandler());
                        }
                    });

            // 发起异步连接操作
            ChannelFuture f = b.connect(host, port).sync();

            // 当代客户端链路关闭
            f.channel().closeFuture().sync();
        } finally {
            // 优雅退出，释放NIO线程组
            group.shutdownGracefully();
        }
    }

    /**
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        int port = 8080;
        String host = "127.0.0.1";
        if (args != null && args.length > 0) {
            try {
                port = Integer.valueOf(args[0]);
            } catch (NumberFormatException e) {
                // 采用默认值
            }
        }
        new EchoClient().connect(port, host);
    }
}

EchoClientHandler：客户端数据处理

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package nettyTcp01.echo;

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

public class EchoClientHandler extends ChannelHandlerAdapter {

    private int counter;

    static final String ECHO_REQ = "Hi, Lilinfeng. Welcome to Netty.$_";

    /**
     * Creates a client-side handler.
     */
    public EchoClientHandler() {
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        // ByteBuf buf = UnpooledByteBufAllocator.DEFAULT.buffer(ECHO_REQ
        // .getBytes().length);
        // buf.writeBytes(ECHO_REQ.getBytes());
        for (int i = 0; i < 10; i++) {
            ctx.writeAndFlush(Unpooled.copiedBuffer(ECHO_REQ.getBytes()));
        }
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String requestBody = (String) msg;
        System.out.println("This is " + ++counter + " times receive server : [" + requestBody + "]");
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

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

 EchoServer：服务器端

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package nettyTcp01.echo;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
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.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

public class EchoServer {
    public void bind(int port) throws Exception {
    // 配置服务端的NIO线程组
    EventLoopGroup bossGroup = new NioEventLoopGroup();
    EventLoopGroup workerGroup = new NioEventLoopGroup();
    try {
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup)
            .channel(NioServerSocketChannel.class)
            .option(ChannelOption.SO_BACKLOG, 100)
            .handler(new LoggingHandler(LogLevel.INFO))
            .childHandler(new ChannelInitializer<SocketChannel>() {
            @Override
            public void initChannel(SocketChannel ch)
                throws Exception {
                ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());
                ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024,delimiter));
                ch.pipeline().addLast(new StringDecoder());
                ch.pipeline().addLast(new EchoServerHandler());
            }
            });

        // 绑定端口，同步等待成功
        ChannelFuture f = b.bind(port).sync();

        // 等待服务端监听端口关闭
        f.channel().closeFuture().sync();
    } finally {
        // 优雅退出，释放线程池资源
        bossGroup.shutdownGracefully();
        workerGroup.shutdownGracefully();
    }
    }

    public static void main(String[] args) throws Exception {
    int port = 8080;
    if (args != null && args.length > 0) {
        try {
        port = Integer.valueOf(args[0]);
        } catch (NumberFormatException e) {
        // 采用默认值
        }
    }
    new EchoServer().bind(port);
    }
}

 EchoServerHandler：服务器数据处理

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package nettyTcp01.echo;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

@Sharable
public class EchoServerHandler extends ChannelHandlerAdapter {

    int counter = 0;

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
        throws Exception {
    String responseBody = (String) msg;
    System.out.println("This is " + ++counter + " times receive client : ["+ responseBody + "]");
    responseBody += "$_";
    ByteBuf echo = Unpooled.copiedBuffer(responseBody.getBytes());
    ctx.writeAndFlush(echo);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
    cause.printStackTrace();
    ctx.close();// 发生异常，关闭链路
    }
}