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2024-06-06 03:05| 来源: 网络整理| 查看: 265

什么是TCP粘包拆包

简单的来讲，就是多次TCP请求传递的msg，由于TCP的请求没有隔离，造成服务端接收到消息不知道哪些字节是属于同一个请求的。

拆包：某一次TCP请求的msg被拆开读取

粘包：某一次TCP请求的msg包含了其他请求的字节

粘包拆包问题实例

问题示范就不贴全部代码了

客户端Handler

package com.leolee.netty.demo.unpackAdherepackage; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import java.nio.charset.Charset; /** * @ClassName MyClientHandler * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyClientHandler extends SimpleChannelInboundHandler { private int count; //连续发送10条信息，测试服务端接受的消息的拆包粘包情况 @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); for (int i = 0; i < 10; i++) { ByteBuf byteBuf = Unpooled.copiedBuffer("hello server " + i + "|", Charset.forName("utf-8")); channel.writeAndFlush(byteBuf); } } @Override protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception { byte[] bytes = new byte[msg.readableBytes()]; msg.readBytes(bytes); String message = new String(bytes, Charset.forName("utf-8")); System.out.println("客户端接收到的数据:"); System.out.println(message); System.out.println("客户端接收到数据量:" + ++this.count); } }

服务端Handler

package com.leolee.netty.demo.unpackAdherepackage; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import java.nio.charset.Charset; import java.util.UUID; /** * @ClassName MyServerHandler * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyServerHandler extends SimpleChannelInboundHandler { private int count; @Override protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception { byte[] bytes = new byte[msg.readableBytes()]; msg.readBytes(bytes); String message = new String(bytes, Charset.forName("utf-8")); System.out.println("服务端接收到的数据:"); System.out.println(message); System.out.println("服务端接收到数据量:" + ++this.count); ByteBuf byteBuf = Unpooled.copiedBuffer(UUID.randomUUID().toString() + "\n", Charset.forName("utf-8")); ctx.writeAndFlush(byteBuf); } }

拆包粘包现象：

自定义协议：

package com.leolee.netty.demo.unpackAdherepackage.protocol; /** * @ClassName MessageProtocol * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MessageProtocol { private int length;//读取的长度 private byte[] content; public int getLength() { return length; } public void setLength(int length) { this.length = length; } public byte[] getContent() { return content; } public void setContent(byte[] content) { this.content = content; } }

自定义编码器：

package com.leolee.netty.demo.unpackAdherepackage.protocol; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; /** * @ClassName MessageEncoder * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MessageEncoder extends MessageToByteEncoder { @Override protected void encode(ChannelHandlerContext ctx, MessageProtocol msg, ByteBuf out) throws Exception { System.out.println("自定义编码器被调用"); out.writeInt(msg.getLength()); out.writeBytes(msg.getContent()); } }

自定义解码器：

package com.leolee.netty.demo.unpackAdherepackage.protocol; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.ReplayingDecoder; import java.util.List; /** * @ClassName MessageDecoder * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MessageDecoder extends ReplayingDecoder { @Override protected void decode(ChannelHandlerContext ctx, ByteBuf in, List out) throws Exception { System.out.println("自定义解码器被调用"); int length = in.readInt(); byte[] bytes = new byte[length]; in.readBytes(bytes); MessageProtocol messageProtocol = new MessageProtocol(); messageProtocol.setLength(length); messageProtocol.setContent(bytes); out.add(messageProtocol); } }

客户端代码修改：增加编码器

package com.leolee.netty.demo.unpackAdherepackage; import com.leolee.netty.demo.unpackAdherepackage.protocol.MessageEncoder; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; /** * @ClassName MyClientInitializer * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyClientInitializer extends ChannelInitializer { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast(new MessageEncoder());//加入自定义编码器 pipeline.addLast(new MyClientHandler()); } }

客户端handler

package com.leolee.netty.demo.unpackAdherepackage; import com.leolee.netty.demo.unpackAdherepackage.protocol.MessageProtocol; import io.netty.buffer.ByteBuf; import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import java.nio.charset.Charset; /** * @ClassName MyClientHandler * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyClientHandler extends SimpleChannelInboundHandler { private int count; //连续发送10条信息，测试服务端接受的消息的拆包粘包情况 @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); for (int i = 0; i < 10; i++) { String message = "hello server " + i + "|"; byte[] bytes = message.getBytes(Charset.forName("utf-8")); int length = message.getBytes(Charset.forName("utf-8")).length; MessageProtocol messageProtocal = new MessageProtocol(); messageProtocal.setLength(length); messageProtocal.setContent(bytes); channel.writeAndFlush(messageProtocal); } } @Override protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception { byte[] bytes = new byte[msg.readableBytes()]; msg.readBytes(bytes); String message = new String(bytes, Charset.forName("utf-8")); System.out.println("客户端接收到的数据:"); System.out.println(message); System.out.println("客户端接收到数据量:" + ++this.count); } }

服务端代码修改：增加解码器

package com.leolee.netty.demo.unpackAdherepackage; import com.leolee.netty.demo.unpackAdherepackage.protocol.MessageDecoder; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; /** * @ClassName MyServerInitializer * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyServerInitializer extends ChannelInitializer { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast(new MessageDecoder()); pipeline.addLast(new MyServerHandler()); } }

服务端handler：

package com.leolee.netty.demo.unpackAdherepackage; import com.leolee.netty.demo.unpackAdherepackage.protocol.MessageProtocol; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import java.nio.charset.Charset; /** * @ClassName MyServerHandler * @Description: TODO * @Author LeoLee * @Date 2020/11/22 * @Version V1.0 **/ public class MyServerHandler extends SimpleChannelInboundHandler { private int count; @Override protected void channelRead0(ChannelHandlerContext ctx, MessageProtocol msg) throws Exception { int length = msg.getLength(); byte[] content = msg.getContent(); System.out.println("服务端接收到的数据:"); System.out.println(new String(content, Charset.forName("utf-8"))); System.out.println("服务端接收到数据量:" + ++this.count); } }

测试：

自定义解码器被调用服务端接收到的数据: hello server 0| 服务端接收到数据量:1 自定义解码器被调用服务端接收到的数据: hello server 1| 服务端接收到数据量:2 自定义解码器被调用服务端接收到的数据: hello server 2| 服务端接收到数据量:3 自定义解码器被调用服务端接收到的数据: hello server 3| 服务端接收到数据量:4 自定义解码器被调用服务端接收到的数据: hello server 4| 服务端接收到数据量:5 自定义解码器被调用服务端接收到的数据: hello server 5| 服务端接收到数据量:6 自定义解码器被调用服务端接收到的数据: hello server 6| 服务端接收到数据量:7 自定义解码器被调用服务端接收到的数据: hello server 7| 服务端接收到数据量:8 自定义解码器被调用服务端接收到的数据: hello server 8| 服务端接收到数据量:9 自定义解码器被调用服务端接收到的数据: hello server 9| 服务端接收到数据量:10

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