就是在TCP异步通信中，服务端采用BeginRead函数接收数据。采用的是递归循环接收，并且我用的是自定义数据包的形式，就是数据包=包头（包头中包含包体长度字段）+包体，但是为何每次解析玩一个正确的数据包后，紧接着后面的数据就是错误的数据为何呢，是什么原因呢？比如正确的数据包总长度是325个字节，头长为13个固定字节，其中包含一个4字节长度定义的是数据体的长度。但是实际现象是，在处理完一个接受到的完整数据包后，紧接着后面新收到的20个字节，中进行解析发现数据体长度为-425545998，又看了下数据确实不对，那这是因为什么原因引起的呢？
贴出部分代码如下：
public void HandleDataReceived(IAsyncResult ar)
{
StateObject state = null;
try
{
//结束读取
state = (StateObject)ar.AsyncState;
int ret = state.CurrtStream.EndRead(ar);
MinPacketLength = new TcpHeaderData().GetByteData().Length;
if (ret == 0)
{
if (ClientDisConnect != null)
{
//IsAlive = false;
IsConnected = false;
ClientDisConnect(ClientIp);
}
return;//表示当前连接断开，则退出，直接返回
}
byte[] currentData = new byte[0];
var temop = new byte[0];
lock (lokObjHisData)
{
temop = HistoryData;
currentData = new byte[HistoryData.Length + state.buffer.Length];
Buffer.BlockCopy(HistoryData, 0, currentData, 0, HistoryData.Length);
Buffer.BlockCopy(state.buffer, 0, currentData, HistoryData.Length, state.buffer.Length);
HistoryData = currentData;//由于每次判断粘包半包，都是不断累加判断的过程，因此这里当条件不满足完整包时，每次都会累加
}
if (currentData.Length < MinPacketLength)
{
Console.WriteLine("当前线程ID为:{0},当前数据包长度小于最小包大小，继续叠加，总次数为:{1}次,+++++++++++++++++++++++++++++",
Thread.CurrentThread.ManagedThreadId, ++globalLessMinPacketNum);
return;
}
else
{
TcpHeaderData headData = new TcpHeaderData();
var isSuc = headData.Filter(currentData);
var contentLen = headData.ContentLength;//解析到内容长度
var sumSize = MinPacketLength + contentLen;//得到数据包总大小
if (contentLen < 0 || sumSize > 65536)
{
lock (lokObjHisData) { HistoryData = new byte[0]; }
Console.WriteLine("当前线程ID为:{0},当前数据包长度异常，总大小为{1}字节,将进行丢弃，总丢弃次数为:{2}次,+++++++++++++++++++++++++++++",
Thread.CurrentThread.ManagedThreadId, sumSize, ++globalCurrentExceptNum);
return;
}
if (currentData.Length == sumSize)
{
//完整包则直接处理
TcpPacketData sumData = new TcpPacketData();
var isSucs = sumData.Filter(currentData);
state.TcpData = sumData;
lock (lokObjHisData)
{
HistoryData = new byte[0];//每次处理完整包后重置
}
Console.WriteLine("当前线程ID为:{0},当前数据包大小相等,总相等次数为:{1},-----------------------------------", Thread.CurrentThread.ManagedThreadId, ++globalStatSameNum);
}
else if (currentData.Length > sumSize)
{
//大于完整包则截取后，处理，因为数据包字节流长度与实际不符，肯定不能正确解析到数据，
var realData = new byte[sumSize];
Buffer.BlockCopy(currentData, 0, realData, 0, sumSize);
TcpPacketData sumData = new TcpPacketData();
var isSucs = sumData.Filter(realData);
state.TcpData = sumData;
var tempData = new byte[currentData.Length - sumSize];
Buffer.BlockCopy(currentData, sumSize, tempData, 0, currentData.Length - sumSize);
//当前条件下，要把处理完毕后，结余的字节重新赋值，便于衔接当前字节流处理机制，HistoryData.Length != 0 && HistoryData[0] == (byte)44
TcpHeaderData headData1 = new TcpHeaderData();
var minLen = new TcpHeaderData().GetByteData().Length;
if (tempData.Length < minLen)
{
lock (lokObjHisData) { HistoryData = tempData; }
Console.WriteLine("当前线程ID为:{0},当前结余字节数不满足正常大小，总次数为:{1},继续叠加！！！！！！！！！！！！！！！！！", Thread.CurrentThread.ManagedThreadId, ++globalStatByLen);
}
else
{
var isSuc1 = headData1.Filter(tempData);
var contentLen1 = headData1.ContentLength;//解析到内容长度
var sumSize1 = MinPacketLength + contentLen1;//得到数据包总大小
if (contentLen1 < 0 || contentLen1 > 65536)
{
lock (lokObjHisData) { HistoryData = new byte[0]; }
Console.WriteLine("当前线程ID为:{0},当前结余数据包长度异常，总大小为{1}字节,将进行丢弃，总丢弃次数为:{2}次,+++++++++++++++++++++++++++++",
Thread.CurrentThread.ManagedThreadId, sumSize1, ++globalStatExceptNum);
}
else
{
lock (lokObjHisData) { HistoryData = tempData; }
Console.WriteLine("当前线程ID为:{0},结余字节数※※※※※※※※※※※※※※※※※※※※※※※{1}", Thread.CurrentThread.ManagedThreadId, tempData.Length);
}
}
}
else
{
Console.WriteLine("当前线程ID为:{0},当前接收数据大小※※※※※※※※※※※※※※※※※※※※※※※{1}", Thread.CurrentThread.ManagedThreadId, ret);
return;
}
}
Console.WriteLine("当前线程ID为:{0},tcpClient.ReceiveBufferSize=================================,{1}", Thread.CurrentThread.ManagedThreadId, state.currentTCPClient.ReceiveBufferSize);
Console.WriteLine("当前线程ID为:{0},tcpClient.SendBufferSize=================================,{1}", Thread.CurrentThread.ManagedThreadId, state.currentTCPClient.SendBufferSize);
//接收数据处理线程
ThreadPool.QueueUserWorkItem(new WaitCallback(ReceiveCallBack), state);
}
catch (Exception ex)
{
lock (lokObjHisData)
{
HistoryData = new byte[0];//出现错误也重置
}
IsConnected = false;
}
finally
{
if (tcpClient != null && tcpClient.Connected)
{
state.CurrtStream.BeginRead(state.buffer, 0, state.buffer.Length, new AsyncCallback(HandleDataReceived), state);//递归循环接收
}
}
}
