利用 Java 下載 HTTP 網絡上的檔案 (Use Java to download file from HTTP)

import java.io.IOException;
import java.net.ConnectException;
import java.net.URL;
import java.io.InputStream;
import java.io.FileOutputStream;

public static void download(String source, String destination) throws IOException, ConnectException{
    InputStream is = new URL(source).openConnection().getInputStream();
    FileOutputStream fos = new FileOutputStream(destination);
    byte[] buffer = new byte[1024];
    for (int length; (length = is.read(buffer)) > 0; fos.write(buffer, 0, length));
    fos.close();
    is.close();
}

此方法亦可以下載 FTP 的檔案，若 FTP 伺服器需要登入身份可利用 FTP URL 格式來登入伺服器
例如 ftp://username:password@www.url.com:port/file.ext
This method can download files in FTP, if FTP Server require login identify to use FTP URL format to login the server
for example ftp://username:password@www.url.com:port/file.ext