限制带宽，同时下载 [英] Limit the bandwidth while downloading

问题描述

我有一个应用程序可以使用Internet连接来下载数据。我使用的HttpURLConnection 做到这一点。

问题：我的应用程序水渠网络带宽，因此用户会慢慢地浏览他们的浏览器。我希望让他们任意设置本身的带宽限制，而不是像<一个href="http://www.digit.in/mobile-phones/how-to-set-internet-data-limit-on-android-phones-and-tablets-20050.html"相对=nofollow>这个网站。我已经知道这件事。

问：如何设置带宽限制，同时下载？例如：500 KB / s（每秒千字节）

。

下面是我的方法下载文件：

  //这是状态codeS。
公共静态最终诠释下装= 0;
公共静态最终诠释PAUSED = 1;
完善的公共静态最终诠释= 2;
公共静态最终诠释已取消= 3;
公共静态最终诠释ERROR = 4;

私人长时间下载;
私人诠释状态;

私人无效downloadFile（字符串requestUrl）抛出IOException异常{

    的InputStream流= NULL;
    RandomAccessFile的输出= NULL;
    状态=下载;
    下载= 0;
    网址URL =新的URL（requestUrl）;

    尝试 {
        System.setProperty（http.keepAlive，假）;
        输出=新的RandomAccessFile（my_directory，RW）;

        //以URL打开连接。
        HttpURLConnection的连接=（HttpURLConnection类）url.openConnection（）;
        connection.setConnectTimeout（5000）;
        connection.connect（）;

        //确保响应code是在200范围内。
        INT状态code = connection.getResponse code（）;
        如果（状态code！= 200）{
            状态=错误;
        }

        流= connection.getInputStream（）;
        而（状态==下载）{
            字节的缓冲区[] =新的字节[1024];

            //从服务器读入缓冲区。
            INT读= stream.read（缓冲区）;
            如果（阅读== -1）
                打破;

            //写入缓冲区文件。
            output.write（缓冲，0，读）;
            下载+ =读取;
        }
        状态==齐全;

    }赶上（例外五）{
        状态=错误;
    } 最后 {
        如果（输出！= NULL）{
            尝试 {
                output.close（）;
            }赶上（例外五）{}
        }

        //关闭连接到服务器。
        如果（流！= NULL）{
            尝试 {
                stream.close（）;
            }赶上（例外五）{}
        }
    }
}
 

解决方案

如果你有一个插槽你可以只设置接收缓冲区大小为所需的带宽时延产品，但是，你不这样做，你就只能睡之间接听电话。实验或一些基于反馈的运算将产生适当的睡眠间隔。

I have an app that can use internet connection to downloading data. I'm using HttpURLConnection to do that.

Problem: My app drains the internet bandwidth, so users will browsing slowly on their Browser. I want to make them optionally to set the bandwidth limit by itself, not like this site. I have knew about it.

Question: How to set the bandwidth limit while downloading? For example: 500 KB/s (KiloBytes per second).

Here's my method to download a file:

// These are the status codes.
public static final int DOWNLOADING = 0;
public static final int PAUSED = 1;
public static final int COMPLETE = 2;
public static final int CANCELLED = 3;
public static final int ERROR = 4;

private long downloaded;
private int status;

private void downloadFile(String requestUrl) throws IOException {

    InputStream stream = null;
    RandomAccessFile output = null;
    status = DOWNLOADING;
    downloaded = 0;
    URL url = new URL(requestUrl);

    try {
        System.setProperty("http.keepAlive", "false");
        output = new RandomAccessFile(my_directory, "rw");

        // Open connection to URL.
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setConnectTimeout(5000);
        connection.connect();

        // Make sure response code is in the 200 range.
        int statusCode = connection.getResponseCode();
        if (statusCode != 200) {
            status = ERROR;
        }

        stream = connection.getInputStream();
        while (status == DOWNLOADING) {
            byte buffer[] = new byte[1024];

            // Read from server into buffer.
            int read = stream.read(buffer);
            if (read == -1)
                break;

            // Write buffer to file.
            output.write(buffer, 0, read);
            downloaded += read;
        }
        status == COMPLETE;

    } catch (Exception e) {
        status = ERROR;
    } finally {
        if (output != null) {
            try {
                output.close();
            } catch (Exception e) {}
        }

        // Close connection to server.
        if (stream != null) {
            try {
                stream.close();
            } catch (Exception e) {}
        }
    }
}

解决方案

If you had a Socket you could just set the receive buffer size to the desired bandwidth-delay product, but, as you don't, you will just have to sleep between receive calls. Experiment or some feedback-based arithmetic will yield the appropriate sleep intervals.

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