当我使用 httpurlconnection 下载文件时，java 消耗大量内存？为什么？

Question

这是我的代码，当我运行它时，它会正确下载文件，但可能会在电脑上使用大量内存。例如:我的 RAM 是 2.02 GB，当我运行应用程序时，我的 RAM 会上升到 3GB，从而降低我的电脑速度。我使用 wampserver 作为我的网络服务器和我的代码，并将 http header 设置为可能的对象，我正确下载文件，感谢您的帮助。

private void downloadFile() {
    try {
        this.response = this.con.getInputStream();
        this.bis = new BufferedInputStream(this.response, 1024 * 1024);
        //int responseCode = this.con.getResponseCode();
        this.responseContentSize = this.con.getContentLength();

        //check kon bebin meghadare bargashti content ba on range ke to behesh gofti mosavi hast ya kheir
        if (this.responseContentSize == (this.end_range - this.start_range) + 1) {
            //fpointer = new RandomAccessFile(this.filePath, "rw");
            //fpointer.seek(this.start_range);
            byte buffer[] = new byte[MAX_BUFFER_SIZE];
            //out = new FileOutputStream(this.filePath);
            makeTmpFile();
            out = new FileOutputStream(this.tmpdir + this.tmpFilename);
            bos = new BufferedOutputStream(out, 1024 * 1024);
            sharedDownloadStatus.setCell(this.threadIndex, STATUS, 1);//downloading
            while (true) {
                //int read = response.read(buffer, 0, this.MAX_BUFFER_SIZE);
                int read = bis.read(buffer, 0, this.MAX_BUFFER_SIZE);
                if (read == -1)
                    break;
                //out.write(buffer, 0, read);
                //fpointer.write(buffer, 0, read);
                bos.write(buffer, 0, read);
                downloadedBytes += read;
                sharedDownloadStatus.setCell(this.threadIndex, DOWNLOADED, downloadedBytes);
            }

            if (bos != null)
                bos.close();
            if (out != null)
                out.close();
            if (fpointer != null)
                fpointer.close();
            if (bis != null)
                bis.close();
            if (response != null)
                response.close();
            sharedDownloadStatus.setCell(this.threadIndex, STATUS, 2);//finish
        }
    } catch (IOException e) {
        sharedDownloadStatus.setCell(this.threadIndex, STATUS, 0);//error
        log.setLog("func : downloadFile =>\n couldnt download file\n" + e.getMessage());
    }

}

Answer 1

您不需要兆字节缓冲区，但主要问题是 HttpURLConnection 将缓冲所有内容，除非固定长度或分块传输模式生效，这是由服务器而不是客户端控制的。