来自 Docker 容器中 Tomcat9/JDK8 的 Java Authenticator“服务器重定向太多次”答案

【问题标题】：Java Authenticator "Server redirected too many times" from Tomcat9/JDK8 in Docker container来自 Docker 容器中 Tomcat9/JDK8 的 Java Authenticator“服务器重定向太多次”
【发布时间】：2020-07-13 17:00:02
【问题描述】：

我正在从共享点列表的固定 URL（用于测试）下载 pdf 文件。在基于独立 VM 的 tomcat9 上运行代码时，它显示 pdf，但如果从基于 Docker 的 tomcat9 运行相同的工作代码，则它给服务器重定向太多次（20）。下面是代码段-

String attachtmentname = "https://<full url>";
String file_name = "<file>.pdf";
String Userid = "<some id>";
String password = "<some password>";
response.setHeader("Content-type", "application/pdf");
response.setHeader("ReportPDF", "content-description");
response.setHeader("Content-Disposition", "inline; filename=" + file_name);
response.setHeader("Cache-Control", "cache,must-revalidate");
System.setProperty("http.proxyUser", Userid);
System.setProperty("http.proxyPassword", password);
Authenticator.setDefault(new Authenticator() {
            
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(Userid, password.toCharArray());
                }
            });
            CookieHandler.setDefault(new CookieManager(null, CookiePolicy.ACCEPT_ALL));
BufferedInputStream in = new BufferedInputStream(new URL(attachtmentname).openStream());
<rest of the code for reading pdf file>

出现“服务器重定向次数过多 (20)”错误

java.net.ProtocolException: Server redirected too many  times (20)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1908)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:268)
    at java.net.URL.openStream(URL.java:1068)

【问题讨论】：

标签： docker https java-8 tomcat9 authenticator

【解决方案1】：

使用 Java nio 库让它工作。下面是测试代码，如果它对某人有帮助。

String attachtmentname = "https://full url/somefile.pdf";
String Userid = "domain\\username";
String password = "password"; 

        Authenticator.setDefault(new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(Userid, password.toCharArray());
                }
            });
URL url = new URL(attachtmentname);
try (InputStream in = url.openStream()) {
    Path pwd = Paths.get("Somepath\\someFile1.pdf").toAbsolutePath();
    out.println(pwd);
    
  Files.copy(in, pwd, StandardCopyOption.REPLACE_EXISTING);
} catch (Exception e) {
   e.printStackTrace();
}

【讨论】：