Java 下載檔案並開啟檔案

今天有前輩再問應該如何用steam下載檔案，下載後將其開啟
隨便找篇ppt來當下載的來源
如果你是該作者覺得這樣很不妥歡迎跟我聯繫xd

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

public class Test {
    public static void main(String []args) throws InterruptedException, NoSuchAlgorithmException, IOException, KeyManagementException {
        downloadFile("https://c.nknu.edu.tw/affair/UploadFile/Files/Files/envedu_1117163234.ppt");
    }

    private final static String CMD = "rundll32 url.dll,FileProtocolHandler %s";

    public static void openFile(String path) throws IOException, InterruptedException {
        if (new File(path).exists() == false) throw new IOException("No File");
        Process process = Runtime.getRuntime().exec(String.format(CMD, path));
        process.waitFor();
    }

    private final static String DOWNLOAD_FOLDER = "C:/Users/C.Y.Fang/Downloads/%s";

    public static void downloadFile(String url) throws IOException, NoSuchAlgorithmException, InterruptedException,  KeyManagementException {
        String[] array = url.split("/");
        String fileName = array[array.length - 1];
        array = null;
        System.out.println(fileName);
        boolean isHttps = url.toUpperCase().contains("HTTPS") ? true : false;


        if (isHttps) {
            SSLContext sslContext = SSLContext.getInstance("SSL");
            sslContext.init(null, trustAllCerts, new SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());
        }

        URL u = new URL(url);
        ReadableByteChannel readableByteChannel = Channels.newChannel(u.openStream());
        String path = String.format(DOWNLOAD_FOLDER, fileName);
        FileOutputStream fileOutputStream = new FileOutputStream(path);
        fileOutputStream.getChannel().transferFrom(readableByteChannel, 0, Long.MAX_VALUE);
        fileOutputStream.flush();
        fileOutputStream.close();
        fileOutputStream = null;
        readableByteChannel.close();
        readableByteChannel = null;
        openFile(path);
    }

    static TrustManager[] trustAllCerts = new TrustManager[]{
            new X509TrustManager() {
                public X509Certificate[] getAcceptedIssuers() {
                    return null;
                }

                public void checkClientTrusted(X509Certificate[] certs, String authType) {
                }

                public void checkServerTrusted(X509Certificate[] certs, String authType) {
                }
            }
    };
}

執行結果：

參考資料：
https://docs.microsoft.com/zh-tw/windows/desktop/api/shellapi/nf-shellapi-shellexecutea
https://confluence.atlassian.com/stashkb/could-not-generate-dh-keypair-on-ssl-715129360.html