Java 根据外链URL下载文件，下载到指定路径并可重新命名文件名称

/**
 *
 * @param remoteURL 下载文件的外链url链接
 * @param fileDirectory 下载到指定的目录路径
 * @param fileName  下载后的文件名称
 * @return
 */
public static int downloadFile(String remoteURL,String fileDirectory,String fileName) {

    remoteURL = urlEncodeURL(remoteURL);

    Path p = Paths.get(fileDirectory);
    File f_p = p.toFile();

    try {
        if (!f_p.exists()) {
            f_p.mkdir();
        }
        File f = new File(p.toAbsolutePath().toString() + "/" + fileName);


        if (!f.exists()) {
            f.createNewFile();
        }

        FileOutputStream fos = new FileOutputStream(f);
        byte[] pb = new byte[1024];

        URL url = new URL(remoteURL);
        URLConnection urlc = url.openConnection();
        InputStream inputstream = urlc.getInputStream();
        int length = -1;
        while (true) {
            length = inputstream.read(pb);
            if (length < 0) {
                fos.flush();
                break;
            } else {
                fos.write(pb, 0, length);
            }
        }
        inputstream.close();
        fos.close();
        return 0;
    } catch (Exception e) {
        e.printStackTrace();
        return -1;
    }
}
//将url中的中文转码

public static String urlEncodeURL(String str) {
    try {
        String result = URLEncoder.encode(str, "UTF-8");
        result = result.replaceAll("%3A", ":").replaceAll("%2F", "/").replaceAll("\\+", "%20");//+实际上是 空格 url encode而来
        return result;
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    return null;
}
//测试

public static void main(String[] angs) throws Exception {
    //下载exe程序
    UrlDownloadUtil.downloadFile("外链","下载到指定路径","下载后的指定文件名");
}