我的问题是httpclient从来没有到达目标。目标是在同一个网络上（所以我不需要代理），它肯定是向上的。而且超时设置得相当高（120秒），服务器能够在不到一秒钟的时间内做出响应。使用其他应用程序或 curl 一切正常。
这是我的代码，我尝试了两种设置凭据的方法，它们都用注解标记。在我的测试中，我先启用了一个，然后启用了另一个：

HttpRequest request = HttpRequest.newBuilder()
    .uri(new URI( "https://target:8443/foo/bar"))
    .version(HttpClient.Version.HTTP_1_1)
    // approach 1:
    .header("Authorization", basicAuth("foo", "bar"))
    .timeout(Duration.ofSeconds(120)).POST(HttpRequest.BodyPublishers.ofFile(tempFile.toPath())).build();

HttpResponse<String> response = HttpClient.newBuilder()
    /* approach 2:
    .authenticator(new Authenticator() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            System.err.println("Was asked for a password");
            return new PasswordAuthentication("foo", "bar".toCharArray());
        }
    })
    */
    .followRedirects(HttpClient.Redirect.ALWAYS)
    .build()
    .send(request, HttpResponse.BodyHandlers.ofString());

与此相反，这一点很有效：

curl -u foo:bar -X POST -H "content-type: application/vnd.lucidworks-document" https://target:8443/foo/bar --data-binary @test.json -v

我的java代码引发以下错误：

2021-04-25 10:26:56.730 INFO 12316 --- [SelectorManager] jdk.httpclient.HttpClient               CHANNEL: Read error signalled on channel java.nio.channels.SocketChannel[closed]: java.io.IOException: connection closed locally
    at java.net.http/jdk.internal.net.http.HttpClientImpl.send(HttpClientImpl.java:561)
    at java.net.http/jdk.internal.net.http.HttpClientFacade.send(HttpClientFacade.java:119)
...
Caused by: java.net.ConnectException: Connection timed out: no further information
    at java.base/sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at java.base/sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:779)
    at java.net.http/jdk.internal.net.http.PlainHttpConnection$ConnectEvent.handle(PlainHttpConnection.java:128)
    at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.handleEvent(HttpClientImpl.java:957)
    at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.lambda$run$3(HttpClientImpl.java:912)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.run(HttpClientImpl.java:912)

启用的日志不会显示太多，但这行代码让我觉得身份验证可能不起作用，因此连接会“卡住”？！？

MISC: Applying jdk.internal.net.http.AuthenticationFilter@43b3184

我知道有些版本的java存在我描述的问题，但我在当前版本的OpenJDKJava11（11.0.11+9）和15（15.0.2+7）上尝试了这个方法，仍然有相同的体验。