Java网络文件传输问题 [英] Java network file transfer problem
问题描述
这是服务器代码:
ServerSocket servsock = new ServerSocket(13267);
while(true){
System.out.println(Waiting ...);
Socket sock = servsock.accept();
System.out.println(Accepted connection:+ sock);
文件myFile = new File(test.txt);
FileInputStream in = new FileInputStream(myFile);
OutputStream out = sock.getOutputStream();
int bytes = 0;
byte [] buffer = new byte [8192];
int len; ((len = in.read(buffer))> 0){
out.write(buffer,0,len);
while
字节+ = len;
System.out.println(Transfer completed,+ bytes +bytes sent);
out.flush();
sock.close();
$ b这是客户端代码:
Socket sock = new Socket(192.168.0.100,13267);
System.out.println(Connecting to:+ sock);
InputStream in = sock.getInputStream();
FileOutputStream out = new FileOutputStream(received.txt);
int bytes = 0;
byte [] buffer = new byte [8192];
int len;
long start = System.currentTimeMillis(); ((len = in.read(buffer))> 0){
out.write(buffer,0,len);
while
字节+ = len;
}
long end = System.currentTimeMillis();
out.close();
sock.close();
double kbps =(bytes / 1000)/((end - start)/ 1000);
System.out.println(速度:+ kbps +kbps);
这是因为我正在使用自己的缓冲区,导致所有的操作都变慢或者出现了什么问题?提示&如果你想测量带宽,你不需要发送一个文件,你可以只发送一个文件空白数据。如果文件不够大,建立连接的代价(通常为20毫秒)会使连接速度变慢。
我建议你至少发送数据2到10秒。
这篇文章的示例代码是通过套接字传输数据的最快方式。 Java socket的速度有多快
使用整数算术产生一个浮点数可能会出错。
double kbps =(bytes / 1000)/((end - start)/ 1000);
说字节
是2100和 end - start
是1900,您将获得
pre code> double kbps =(2100/1000) /(1900/1000);
double kbps = 2/1; == 2.
几乎相同(但错误少)
double kbps = bytes /(end - start);
更好
double kbps =(double)bytes /(end - start);
传送空白资料
byte [] bytes = new byte [8 * 1024];
OutputStream out = socket.getOutputStream();
//发送给定时间量的数据,例如2000 ms
long endTime = System.currentTimeMS()+ timeToSendDataMS;
do {
out.write(bytes);
} while(endTime> System.currentTimeMS());
读取空白数据
long total = 0;
byte [] bytes = new byte [8 * 1024];
InputStream in = socket.getInputStream();
int len; ((len = in.read(bytes))!= -1)
total + = len;
I am writing a small java program that can measure the speed of my local network. It is the first time I am working with sockets but I've put together a program that works. The only problem is that the measurements are far from accurate (way too low).
This is the server code:
ServerSocket servsock = new ServerSocket(13267);
while (true) {
System.out.println("Waiting...");
Socket sock = servsock.accept();
System.out.println("Accepted connection : " + sock);
File myFile = new File("test.txt");
FileInputStream in = new FileInputStream(myFile);
OutputStream out = sock.getOutputStream();
int bytes = 0;
byte[] buffer = new byte[8192];
int len;
while ((len = in.read(buffer)) > 0) {
out.write(buffer, 0, len);
bytes += len;
}
System.out.println("Transfer completed, " + bytes + " bytes sent");
out.flush();
sock.close();
}
This is the client code:
Socket sock = new Socket("192.168.0.100", 13267);
System.out.println("Connecting to : " + sock);
InputStream in = sock.getInputStream();
FileOutputStream out = new FileOutputStream("received.txt");
int bytes = 0;
byte[] buffer = new byte[8192];
int len;
long start = System.currentTimeMillis();
while ((len = in.read(buffer)) > 0) {
out.write(buffer, 0, len);
bytes += len;
}
long end = System.currentTimeMillis();
out.close();
sock.close();
double kbps = (bytes / 1000) / ((end - start) / 1000);
System.out.println("Speed: " + kbps + " kbps");
Is this because I am working with my own buffers that slow everything down or what could be the problem? Tips & hints are welcome too.
If you want to measure bandwidth you don't need to send a file, you can just send blank data. If the file isn't large enough, the cost of making the connection (typically 20 ms) will make your connection appear slow.
I suggest you send data for at least 2 to 10 seconds.
This article has sample code on the fastest way to transfer data over a socket. How fast are Java sockets
Using integer arithmetic to produce a floating point is likely to get errors.
double kbps = (bytes / 1000) / ((end - start) / 1000);
Say bytes
is 2100 and end - start
is 1900 you will get
double kbps = (2100 / 1000) / (1900 / 1000);
double kbps = 2 / 1; == 2.
is almost the same as (but with less error)
double kbps = bytes / (end - start);
better
double kbps = (double) bytes / (end - start);
To send blank data
byte[] bytes = new byte[8*1024];
OutputStream out = socket.getOutputStream();
// send data for given amount of time, e.g. 2000 ms
long endTime = System.currentTimeMS() + timeToSendDataMS;
do {
out.write(bytes);
} while(endTime > System.currentTimeMS());
To read blank data
long total = 0;
byte[] bytes = new byte[8*1024];
InputStream in = socket.getInputStream();
int len;
while((len = in.read(bytes)) != -1)
total += len;
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