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,但是,我怎么能用HTTPS做到这一点。如果有人使用过示例API,请帮我找到有用的资源。
答案 0 :(得分:31)
使用Java访问HTTPS网址与访问HTTP网址相同。您可以随时使用
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,您可能需要为测试目的禁用证书验证并信任所有证书。
要做到这一点写:
// 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
答案 1 :(得分:2)
其实我遇到了类似的问题。我无法从HTTPS服务器下载文件。然后我用这个解决方案解决了这个问题:
// But are u denied access?
// well here is the solution.
public static void TheKing_DownloadFileFromURL(String search, String path) throws IOException {
// This will get input data from the server
InputStream inputStream = null;
// This will read the data from the server;
OutputStream outputStream = null;
try {
// This will open a socket from client to server
URL url = new URL(search);
// This user agent is for if the server wants real humans to visit
String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36";
// This socket type will allow to set user_agent
URLConnection con = url.openConnection();
// Setting the user agent
con.setRequestProperty("User-Agent", USER_AGENT);
//Getting content Length
int contentLength = con.getContentLength();
System.out.println("File contentLength = " + contentLength + " bytes");
// Requesting input data from server
inputStream = con.getInputStream();
// Open local file writer
outputStream = new FileOutputStream(path);
// Limiting byte written to file per loop
byte[] buffer = new byte[2048];
// Increments file size
int length;
int downloaded = 0;
// Looping until server finishes
while ((length = inputStream.read(buffer)) != -1)
{
// Writing data
outputStream.write(buffer, 0, length);
downloaded+=length;
//System.out.println("Downlad Status: " + (downloaded * 100) / (contentLength * 1.0) + "%");
}
} catch (Exception ex) {
//Logger.getLogger(WebCrawler.class.getName()).log(Level.SEVERE, null, ex);
}
// closing used resources
// The computer will not be able to use the image
// This is a must
outputStream.close();
inputStream.close();
}
使用此功能...希望您能从这个简单的解决方案中受益。
答案 2 :(得分:1)
除非SSL证书验证失败,否则您应该能够使用完全相同的代码执行此操作。如果它是自签名的ceritifcate,或者证书来自您的系统不知道的CA,通常会发生这种情况。
在这种情况下,您应该在代码中处理证书验证。只有代码的那部分会改变。其他一切都将保持不变。
首先尝试使用相同的代码,看看是否有证书异常。
答案 3 :(得分:0)
下载http vs https没有区别。打开HttpURLConnection到正确的URL并读取结果流。