问题描述
我正在写一个可以测量本地网络速度的小型java程序。这是我第一次使用套接字，但是我已经制定了一个可行的程序。唯一的问题是测量结果不准确（太低）。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。
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;
这篇关于Java网络文件传输问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！