使用 Java 从 HTTPS 服务器下载文件

2022-01-19 00:00:00 network-programming java

我想从使用安全连接协议 HTTPS 的服务器下载文件.我可以在普通服务器上做到这一点，但是，我如何使用 HTTPS 做到这一点.如果有人使用过示例 API，请帮助我找到有用的资源.

I want to download a file from the server which is using the secured connection protocol HTTPS. I could do it in the normal server, But, how I can do it using the HTTPS. If anyone have used the sample API, please help me to find the useful resources.

推荐答案

用Java访问HTTPS url和访问HTTP url是一样的.您可以随时使用

Access an HTTPS url with Java is the same then access an HTTP url. You can always use the

URL url = new URL("https://hostname:port/file.txt");
URLConnection connection = url.openConnection();
InputStream is = connection.getInputStream();
// .. then download the file

但是，当无法验证服务器的证书链时，您可能会遇到一些问题.因此，出于测试目的，您可能需要禁用证书验证并信任所有证书.

But, you can have some problem when the server's certificate chain cannot be validated. So you may need to disable the validation of certificates for testing purposes and trust all certificates.

要做到这一点:

// Create a new trust manager that trust all certificates
TrustManager[] trustAllCerts = new TrustManager[]{
    new X509TrustManager() {
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }
        public void checkClientTrusted(
            java.security.cert.X509Certificate[] certs, String authType) {
        }
        public void checkServerTrusted(
            java.security.cert.X509Certificate[] certs, String authType) {
        }
    }
};

// Activate the new trust manager
try {
    SSLContext sc = SSLContext.getInstance("SSL");
    sc.init(null, trustAllCerts, new java.security.SecureRandom());
    HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
} catch (Exception e) {
}

// And as before now you can use URL and URLConnection
URL url = new URL("https://hostname:port/file.txt");
URLConnection connection = url.openConnection();
InputStream is = connection.getInputStream();
// .. then download the file

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