使用 Java7 下载文件失败 - 多重重定向错误

Question

问题： 无法从 https://apps.irs.gov/app/fatcaFfiList/data/FFIListFull.csv 下载 csv，出现以下错误。

Connecting : https://apps.irs.gov/app/fatcaFfiList/data/FFIListFull.csv java.net.ProtocolException: Server redirected too many times (20) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1636) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254) at FileDownload.downloadFile(FileDownload.java:86) at FileDownload.main(FileDownload.java:54)

目标： 使用 Java

下载 csv

注：在URLConnection conn = uURL.openConnection(proxy);前加上HttpURLConnection.setFollowRedirects(false);并不能解决问题。添加代码后文件变为0字节

重现问题：

java被BAT脚本调用

java -Xmx1024m -classpath "%LIB%\*" -Dbasepath=D:\ FileDownload https://apps.irs.gov/app/fatcaFfiList/data/FFIListFull.csv NoUser NoPassword FFIListFull.csv webproxy 8080>> log.txt

FileDownload.class 用于文件下载

import java.io.*;
import java.net.*;

public class FileDownload {
    public static void main(String[] args) {
        boolean isError = false;
        String iURL = "";
        String iUSR = "";
        String iPWD = "";
        String iOUT = "";
        String iPXY = "";
        int iPPT = -1;
        if (args.length == 6) {
            iURL = args[0];
            iUSR = args[1];
            iPWD = args[2];
            iOUT = args[3];
            iPXY = args[4];
            iPPT = strToInt(args[5]);
        } else {
            isError = true;
        }
        if (isError) {
            System.err
                    .println("Usage: FileDownload <URL> <USERNAME> <PASSWORD> <OUTPUT FILE>\nFileDownload <URL> <USERNAME> <PASSWORD> <OUTPUT FILE> <PROXY HOST> <PROXY PORT>");

            System.exit(1);
        }
        long lStart = System.currentTimeMillis();
        try {
            System.out.printf("Connecting : %s \n", new Object[] { iURL });
            if (args.length == 6) {
                downloadFile(iURL, iUSR, iPWD, iOUT, iPXY, iPPT);
            }
        } catch (IOException e) {
            e.printStackTrace(System.out);
            System.exit(1);
        }
        long lEnd = System.currentTimeMillis();

        long lUsed = lEnd - lStart;

        int iSec = (int) (lUsed / 1024L);

        System.out.printf("Time Used: %d msec (i.e. %d min %d sec)\n",
                new Object[] { Long.valueOf(lUsed), Integer.valueOf(iSec / 60),
                        Integer.valueOf(iSec % 60) });
    }

    public static void downloadFile(String iURL, String iUSR, String iPWD,
            String iOUTFile, String proxyHost, int proxyPort)
            throws IOException {
        final String USER = iUSR;
        final String PASS = iPWD;

        Authenticator.setDefault(new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(USER, PASS.toCharArray());
            }
        });
        URL uURL = new URL(iURL);
        SocketAddress addr = new InetSocketAddress(proxyHost, proxyPort);
        Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);
        
        URLConnection conn = uURL.openConnection(proxy);
        InputStream in = conn.getInputStream();

        int fileSize = getFileSize(uURL, proxy);
        downloadFile(in, fileSize, iOUTFile);
    }

    private static void printDownloadStatus(int downloadedBytes, int totalBytes) {
        if (totalBytes > 0) {
            System.out.printf(
                    "%s out of %s ( %.1f%% ) downloaded\n",
                    new Object[] {
                            formatBytes(downloadedBytes),
                            formatBytes(totalBytes),
                            Double.valueOf(downloadedBytes * 100.0D
                                    / totalBytes) });
        } else {
            System.out.printf("%s downloaded\n",
                    new Object[] { formatBytes(downloadedBytes) });
        }
    }

    private static String formatBytes(int iBytes) {
        String res = "";
        if (iBytes > 1073741824) {
            res = String.format("%.1f GB", new Object[] { Double
                    .valueOf(iBytes / 1024.0D / 1024.0D / 1024.0D) });
        } else if (iBytes > 1048576) {
            res = String
                    .format("%.1f MB", new Object[] { Double
                            .valueOf(iBytes / 1024.0D / 1024.0D) });
        } else if (iBytes > 1024) {
            res = String.format("%.1f KB",
                    new Object[] { Double.valueOf(iBytes / 1024.0D) });
        } else {
            res = String.format("%.1f Bytes",
                    new Object[] { Double.valueOf(iBytes) });
        }
        return res;
    }

    private static int getFileSize(URL url, Proxy proxy) {
        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection) url.openConnection(proxy);
            conn.setRequestMethod("HEAD");
            conn.getInputStream();
            return conn.getContentLength();
        } catch (IOException e) {
            e.printStackTrace(System.out);
            return -1;
        } finally {
            conn.disconnect();
        }
    }

    private static int strToInt(String str) {
        int res = -1;
        try {
            res = Integer.parseInt(str);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return res;
    }
}

Answer 1

找到一个 使用 JScript 嵌入到 bat 中。但是，不是 Java 解决方案。