Netty 是一个高性能、异步事件驱动的 NIO 框架，它提供了对 TCP、UDP 和文件传输的支持，作为一个异步 NIO 框架，Netty 的所有 IO 操作都是异步非阻塞的，通过 Future-Listener 机制，用户可以方便的主动获取或者通过通知机制获得 IO 操作结果。
作为当前最流行的 NIO 框架，Netty 在互联网领域、大数据分布式计算领域、游戏行业、通信行业等获得了广泛的应用，一些业界著名的开源组件也基于 Netty 的 NIO 框架构建。
协议解析代码：
package nettyserver;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.util.ReferenceCountUtil;
import java.util.HashMap;
import java.util.Map;
class MyInHandler extends ChannelInboundHandlerAdapter {
final byte HEAD1 = 0x48;// H
final byte HEAD2 = 0x54;// T
final byte HEAD3 = 0x45;// E
final byte HEAD4 = 0x4D;// M
final byte HEAD5 = 0x50;// P
final byte HEAD6 = 0x3D;// =
public static final String SPLIT1 = "#";
public static Map<String, io.netty.buffer.ByteBuf> dicSn2Buffer = new HashMap<>();
// HTEMP=0026#1533022506#Meter-001#01##
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
{
// 当出现异常就关闭连接
//cause.printStackTrace();
RemoveClient(ctx, "exceptionCaught");
}
@Override
public void channelActive(io.netty.channel.ChannelHandlerContext ctx) throws Exception
{
CTxtHelp.AppendLog("客户端已经连接,sn:" + GetSN(ctx));
}
@Override
public void channelInactive(io.netty.channel.ChannelHandlerContext ctx) throws Exception
{
RemoveClient(ctx, "channelInactive");
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception
{
if (evt instanceof IdleStateEvent)
{
String type = "未知";
IdleStateEvent event = (IdleStateEvent) evt;
if (null != event.state())
{
switch (event.state())
{
case READER_IDLE: type = "read idle"; break;
case WRITER_IDLE: type = "write idle"; break;
case ALL_IDLE: type = "all idle"; break;
default: break;
}
}
RemoveClient(ctx, "超时退出(" + type + ")");
}
else
{
super.userEventTriggered(ctx, evt);
}
}
@Override
public void channelRead(io.netty.channel.ChannelHandlerContext ctx, Object msg)
{
if (!ctx.channel().isActive()) return;
String sn = GetSN(ctx);
if(!dicSn2Buffer.containsKey(sn)) dicSn2Buffer.put(sn, Unpooled.buffer(1024));
io.netty.buffer.ByteBuf oldBuffer = dicSn2Buffer.get(sn);
if (null != msg)
{
io.netty.buffer.ByteBuf recvBuffer = (ByteBuf) msg;
int size = recvBuffer.readableBytes();
if (size > 0)
{
//recvBuffer.markReaderIndex();
oldBuffer.writeBytes(recvBuffer);
ReferenceCountUtil.release(recvBuffer);
//recvBuffer.resetReaderIndex();
//byte[] recv = new byte[size];
//recvBuffer.readBytes(recv);
//CTxtHelp.AppendLog("接收数据：" + CDataHelper.ArrayByteToString(recv));
}
}
byte head1 = 0; byte head2 = 0; byte head3 = 0; byte head4 = 0; byte head5 = 0; byte head6 = 0;
while (oldBuffer.isReadable())
{
oldBuffer.markReaderIndex();
head1 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; } // 掉包处理
if (HEAD1 == head1)// 垃圾包处理
{
head2 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; }
head3 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; }
head4 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; }
head5 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; }
head6 = oldBuffer.readByte(); if (!oldBuffer.isReadable()) { oldBuffer.resetReaderIndex(); return ; }
if (HEAD2 == head2 && HEAD3 == head3 && HEAD4 == head4 && HEAD5 == head5 && HEAD6 == head6)
{
break;
}
else
{
CTxtHelp.AppendLog("Error,Unable to parse the data2");
}
}
else
{
CTxtHelp.AppendLog("Error,Unable to parse the data1");
}
}
int lengthsize = 4;
if (GetWaitRecvRemain(oldBuffer, lengthsize)) { oldBuffer.resetReaderIndex(); return ; }
byte[] arrlen = new byte[lengthsize]; oldBuffer.readBytes(arrlen);
int lengthdata = CDataHelper.String2Int(CDataHelper.ArrayByteToString(arrlen));// if (-1 == len) return;
if (GetWaitRecvRemain(oldBuffer, lengthdata)) { oldBuffer.resetReaderIndex(); return ; }
byte[] source = new byte[lengthdata]; oldBuffer.readBytes(source);
String data = CDataHelper.ArrayByteToString(source);
CTxtHelp.AppendLog("解析后：" + data);
if (null == data || 0 == data.length() || data.length() - 1 != data.lastIndexOf(SPLIT1)) return;
data = data.substring(1, data.length() - 1);
String[] items = data.split(SPLIT1, -1);
if (null == items || 4 != items.length) return;
String uid = items[0];
String taskid = items[1];
int cmd = CDataHelper.String2Int(items[2]);
String content = items[3];
String back = "";
try
{
switch (cmd)
{
case 1: back = "ok"; break;
case 2: break;
case 3: break;
}
}
catch (Exception ex)
{
CTxtHelp.AppendLog("error@" + ex.getMessage());
}
if (!"".equals(back))
{
byte[] sendBuff = GetProtocol(uid, cmd, back);
ByteBuf out = ctx.alloc().directBuffer(sendBuff.length);
out.writeBytes(sendBuff);
ctx.channel().writeAndFlush(out);
}
if (!oldBuffer.isReadable())
{
oldBuffer.clear();
}
else
{
channelRead(ctx, null);
}
}
boolean GetWaitRecvRemain( io.netty.buffer.ByteBuf buf, int len) {
return buf.readerIndex() + len > buf.writerIndex();
}
String GetSN(io.netty.channel.ChannelHandlerContext ctx)
{
return ctx.channel().remoteAddress().toString().replace("/", "");
}
void RemoveClient(io.netty.channel.ChannelHandlerContext ctx, String errmsg)
{
String sn = GetSN(ctx);
CTxtHelp.AppendLog("客户端退出,errmsg：" + errmsg);
if(dicSn2Buffer.containsKey(sn)) {
io.netty.buffer.ByteBuf byteBuf = dicSn2Buffer.get(sn);
ReferenceCountUtil.release(byteBuf);
dicSn2Buffer.remove(sn);
}
ctx.close();
}
byte[] GetProtocol(String uid, int cmd, String msg)
{
String content = SPLIT1 + uid + SPLIT1 +
System.currentTimeMillis() + SPLIT1 +
CDataHelper.lpad(cmd, 2) + SPLIT1 +
msg + SPLIT1;
StringBuilder data = new StringBuilder();
data.append("HTEMP=");
data.append(CDataHelper.lpad(CDataHelper.GetStringLength(content), 4));
data.append(content);
return CDataHelper.StringToByte(data.toString());
}
String lpad(int number, int length) {
String f = "%0" + length + "d";
return String.format(f, number);
}
}
程序结构：
运行结果：
1. 包解析（正常包+掉包+粘包+垃圾包）
2. 超时清理链路
3. 并发测试
来源：oschina
链接：https://my.oschina.net/u/4362830/blog/3451755