使用RandomAccessFile通过Internet下载文件

问题描述

我正在Internet上浏览随机Java代码，并且发现了下载管理器.它使用 RandomAccessFile 下载文件.我无法确定的一件事是它将下载到何处.这是下载文件的方法:

I was browsing the Internet for random Java code, and I found this source code for a download manager. It uses RandomAccessFile to download the files. The one thing I could not figure out though, was where it would download to. Here is the method that downloads the file:

public void startDownload() {
    System.out.println("Starting...");
    RandomAccessFile file = null;
    InputStream stream = null;

    try {
        URL downloadLink = new URL("http://www.website.com/file.txt");

        // Open the connection to the URL
        HttpURLConnection connection = (HttpURLConnection) downloadLink.openConnection();

        // Specify what portion of file to download
        connection.setRequestProperty("Range", "bytes=" + downloaded + "-");

        // Connect to the server
        connection.connect();

        // Make sure the code is in the 200 range
        if (connection.getResponseCode() / 100 != 2) {
            error();
        }

        // Check for valid content length
        int contentLength = connection.getContentLength();
        if (contentLength < 1) {
            error();
        }

        // Set the size for the download if it hasn't been already set
        if (size == -1) {
            size = contentLength;
            stateChanged();
        }

        // Open file and seek to the end of it
        file = new RandomAccessFile(getFileName(downloadLink), "rw");
              // getFileName returns the name of the file mentioned in the URL

        file.seek(downloaded);

        stream = connection.getInputStream();

        while (status == DOWNLOADING) {
            System.out.println("Progress: " + getProgress() + "%");

            // Size the buffer according to how much of the file is left to download
            byte buffer[];
            if (size - downloaded > MAX_BUFFER_SIZE) {
                buffer = new byte[MAX_BUFFER_SIZE];
            } else {
                buffer = new byte[size - downloaded];
            }

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

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

        if (status == DOWNLOADING) {
            status = COMPLETE;
            stateChanged();
        }


    } catch (Exception e) {
        error();
    } finally {
        // Close the stream and RAF
    }
    System.out.println("Done!");
}

很抱歉，如果这很明显.我是今天刚学到的 RandomAccessFile 类的新手.

I am sorry if this is obvious. I am new to the RandomAccessFile class, as I just learned of it today.

推荐答案

它将下载到当前工作目录(即运行Java命令的位置)中，文件名将由 getFileName(downloadLink).

It will download it in the current working directory (i.e. where you run your java command) and the name of the file will be given by getFileName(downloadLink).

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