我正在我的PC上运行一个服务器(C++ Winsock)和一个客户机(Java)。
我将一个大字节数组从我的客户端发送到服务器,虽然传输完成时没有任何错误,但我的传输速度非常慢。举个例子,对于数组大小为200.000字节的数组,传输需要3-5秒(约50 To /s)。
这是正常的吗?我不是专家,但我不应该通过局域网达到更高的速度(大约1Mb/s)吗?
以下是我的简化代码:
客户端(Java)
import ...
public class Client {
public static void main(String[] args) throws IOException {
OutputStream outToServer;
DataOutputStream out = null;
String serverHostname = new String ("...");
int port = ...;
Socket client = null;
try {
client = new Socket(serverHostname, port);
outToServer = client.getOutputStream();
out = new DataOutputStream(outToServer);
int size = 200000;
byte[] b = new byte[size];
new Random().nextBytes(b);
for(int i = 0 ; i < size ; i++){
out.writeByte(b[i]);
}
out.close();
} catch (UnknownHostException e) ...//Exit
catch (IOException e) ...//Exit
client.close();
}
}
和服务器(C++,Winsock)
#undef UNICODE
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>...
// Need to link with Ws2_32.lib
#pragma comment (lib, "Ws2_32.lib")
// #pragma comment (lib, "Mswsock.lib")
#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "..."
int __cdecl main(void)
{
WSADATA wsaData;
int iResult;
SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;
struct addrinfo *result = NULL;
struct addrinfo hints;
int iSendResult;
char recvbuf[DEFAULT_BUFLEN];
int recvbuflen = DEFAULT_BUFLEN;
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) //Return
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
// Resolve the server address and port
iResult = getaddrinfo(NULL, DEFAULT_PORT, &hints, &result);
if (iResult != 0) ...//Return
// Create a SOCKET for connecting to server
ListenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
if (ListenSocket == INVALID_SOCKET) ...//Return
// Setup the TCP listening socket
iResult = bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
if (iResult == SOCKET_ERROR) ...//Return
freeaddrinfo(result);
iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR) ...//Return
// Accept a client socket
ClientSocket = accept(ListenSocket, NULL, NULL);
if (ClientSocket == INVALID_SOCKET) ...//Return
// No longer need server socket
closesocket(ListenSocket);
// Receive until the peer shuts down the connection
int bytes = 0;
do {
iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
if (iResult > 0)
bytes += iResult;
else if (iResult == 0)
//Connection Closing
else
...//Return
} while (iResult > 0);
printf("Received %d bytes\n", bytes);
...//Shutdown and Return
}
发布于 2016-05-31 17:19:43
要么将OutputStream
封装在BufferedOutputStream
中,要么手动缓冲输出(例如,首先将字节收集到数组中,然后使用[#write(byte[])
](https://docs.oracle.com/javase/7/docs/api/java/io/OutputStream.html#write(byte[]%29) )。用每个字节发送数据包肯定会非常慢--请参阅Size of empty UDP and TCP packet?;空that为64个字节,即为1字节数据发送的64+1字节,为可能的传输速率(YMMV )的1/65,您可能会看到,由于消除了VM -> OS通信的额外开销,每个writeByte
命令的传输速率甚至会更高。
直接净传输的经验法则是,如果您打算在短时间内反复发送比通常的以太网数据包(即明显小于1 1KiB,例如100字节)少得多的数据包,那么最好先缓冲它并集体发送它。
https://stackoverflow.com/questions/37551635
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