java在while循环下载过程中如何计算Mbit / s [英] java howto calculate Mbit/s during while loop download

问题描述

我有这个而 循环下载文件

< $（pre> while（（val = bis.read（buffer，0，1024））> 0）{
out.write（buffer，0，val）;
fileSize - = val;
if（fileSize< 1024）{
val =（int）fileSize;
}


试图找出如何显示Mbit / s像许多速度网站一样。 （链接）

http://www.speedtest.net/
。

想要将图像留在而循环中，但我有

看到的例子使用分钟线程发射，但我dunno ..

我不知道数据量，或数据总是1024.

thats关于我认为的问题

任何帮助是grate？

解决方案

我可能会错过订单一般的想法如下：

  long start = System.nanoTime（）; 
 long totalRead = 0; 
 final double NANOS_PER_SECOND = 1000000000.0; 
 final double BYTES_PER_MIB = 1024 * 1024; 
 
 while（（val = bis.read（buffer，0，1024））> 0）{
 // ... 
 totalRead + = val; 
 double speed = NANOS_PER_SECOND / BYTES_PER_MIB * totalRead /（System.nanoTime（） -  start + 1）
} 
  

请注意，这从一开始计算平均速度，而不是当前速度。

I have this while loop downloading a file

while ((val = bis.read(buffer, 0, 1024)) > 0) {
   out.write(buffer, 0, val);
   fileSize -= val;
   if (fileSize < 1024) {
   val = (int) fileSize;
}

Trying to figure out how to show Mbit/s like many speed sites do.(link)
http://www.speedtest.net/ .

Would like the mesurment to stay inside the while loop but i have
seen examples using on-minute-threads firing but i dunno..

I dont know the amount of data, or the data is always 1024.
thats on of the problems i think
Any help is grate?

解决方案

I might be wrong by an order of magnitude or two, by the general idea is as follows:

long start = System.nanoTime();
long totalRead = 0;
final double NANOS_PER_SECOND = 1000000000.0;
final double BYTES_PER_MIB = 1024 * 1024;

while ((val = bis.read(buffer, 0, 1024)) > 0) {
    //...
    totalRead += val;
    double speed = NANOS_PER_SECOND / BYTES_PER_MIB * totalRead / (System.nanoTime() - start + 1)
}

Note that this calculates average speed from the beginning, not the current velocity.

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