计算网络下载速度 [英] Calculating network download speed

问题描述

我已经写了下面的代码来使用java来计算下载速度。
但是它没有给出正确的结果。问题是什么？我的逻辑有问题，还是Java网络类使用的问题？我认为使用java网络类是一个问题任何人可以告诉我究竟是什么问题？

  / *作者：Jinu Joseph Daniel * / 
 import java .IO *。 
 import java.net。*; 
 class bwCalc {
 static class CalculateBw {
 public void calculateUploadBw（）{} 
 public float calculateDownloadRate（int waitTime）throws异常{
 int bufferSize = 1; 
 byte [] data = new byte [bufferSize]; // buffer 
 BufferedInputStream in = new BufferedInputStream（new URL（https://www.google.co.in/）.openStream（））; 
 int count = 0; 
 long startedAt = System.currentTimeMillis（）; 
 long stoppedAt; 
浮动利率; 
 while（（stopAt = System.currentTimeMillis（）） -  startedAt）< waitTime）{
 if（in .read（data，0，bufferSize）！= -1）{
计数++; 
} else {
 System.out.println（Finished）; 
 break; 
} 
} 
 in .close（）; 
 rate = 1000 *（（（float）count * bufferSize * 8 /（stoppedAt  -  startedAt）））/（1024 * 1024）; //以Mbps 
返回率的速率; 
} 
 public float calculateAverageDownloadRate（）throws Exception {
 int times [] = {100,200,300,400,500}; 
 float bw = 0，curBw; 
 int i = 0，len = times.length; 
 while（i  curBw = calculateDownloadRate（times [i ++]）; 
 bw + = curBw; 
 System.out.println（当前速率：+ Float.toString（curBw））; 
} 
 bw / = len; 
 return bw; 
} 
} 
 public static void main（String argc []）throws Exception {
 CalculateBw c = new CalculateBw（）; 
 System.out.println（Float.toString（c.calculateAverageDownloadRate（）））; 
} 
} 
  

解决方案

你的代码有很多问题...

• 你没有检查你正在阅读多少字节

由于内容大小非常小，大部分下载时间与网络延迟有关，所以使用Google的主页进行测试是无用的;您应该尝试下载一个大文件（10+ MB） - UNLESS ，您实际上要测量延迟而不是带宽，在这种情况下，您可以简单地运行ping

• 如果你想得到任何相关的结果，你还需要提供超过500ms - 我会说至少5秒


• 大量的代码风格问题，但那些不太重要li>
  

I have written the follwing code to calculate download speed using java. But it is not giving correct results.What is the problem?.Is there a problem with my logic , or is it a problem with java networking classes usage?I think it is a problem with the usage of java networking classes.Can anybody tell me what exactly the problem is?

/*Author:Jinu Joseph Daniel*/
import java.io.*;
import java.net.*;
class bwCalc {
    static class CalculateBw {
            public void calculateUploadBw() {}
            public float calculateDownloadRate(int waitTime) throws Exception {
               int bufferSize = 1;
               byte[] data = new byte[bufferSize]; // buffer
               BufferedInputStream in = new BufferedInputStream(new URL("https://www.google.co.in/").openStream());
               int count = 0;
               long startedAt = System.currentTimeMillis();
               long stoppedAt;
               float rate;
                while (((stoppedAt = System.currentTimeMillis()) - startedAt) < waitTime) {
                    if ( in .read(data, 0, bufferSize) != -1) {
                    count++;
                } else {
                    System.out.println("Finished");
                    break;
                }
            }
            in .close();
            rate = 1000 * (((float) count*bufferSize*8 / (stoppedAt - startedAt)) )/(1024*1024);//rate in Mbps
            return rate;
        }
    public float calculateAverageDownloadRate() throws Exception{
        int times[] = {100,200,300,400,500};
        float bw = 0,curBw;
        int i = 0, len = times.length;
        while (i < len) {
            curBw = calculateDownloadRate(times[i++]);
            bw += curBw;
            System.out.println("Current rate : "+Float.toString(curBw));
        }
        bw /= len;
        return bw;
    }
}
public static void main(String argc[]) throws Exception {
    CalculateBw c = new CalculateBw();
    System.out.println(Float.toString(c.calculateAverageDownloadRate()));
}
}

解决方案

There are many problems with your code...

• you're not checking how many bytes you are reading
• testing with Google's home page is useless, since the content size is very small and most of the download time is related to network latency; you should try downloading a large file (10+ MB) - UNLESS you actually want to measure latency rather than bandwidth, in which case you can simply run ping
• you also need to give it more than 500ms if you want to get any relevant result - I'd say at least 5 sec
• plenty of code style issues, but those are less important

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