Java http请求GET会导致超时异常，但在浏览器中可以正常运行 [英] Java http request GET causes timeout exception while it works fine in the browser

问题描述

我一直在玩Java中的Http，但遇到了一个奇怪的问题.下面是执行GET方法的片段代码:

I have been playing with Http in Java and I faced a strange problem. Below is a piece code which executes GET method:

OkHttpClient client = new OkHttpClient();
client.setConnectTimeout(100, TimeUnit.SECONDS);
client.setReadTimeout(100, TimeUnit.SECONDS);
Response response = null;
Request request = new Request.Builder()
        .url("https://www.celebritycruises.com/")
        .get()
        .build();
try {
    response = client.newCall(request).execute();
    System.out.println(response.code());
} catch (IOException e) {
    e.printStackTrace();
} 

因此，有些站点(例如Builder中提供的站点)会导致:

So there are some sites (like the one provided in the Builder which cause:

java.net.SocketTimeoutException: timeout
at okio.Okio$3.newTimeoutException(Okio.java:207)
at okio.AsyncTimeout.exit(AsyncTimeout.java:261)
at okio.AsyncTimeout$2.read(AsyncTimeout.java:215)
[...]
Caused by: java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
at sun.security.ssl.InputRecord.read(InputRecord.java:503)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:983)
at sun.security.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:940)

at sun.security.ssl.AppInputStream.read(AppInputStream.java:105)
at okio.Okio$2.read(Okio.java:139)
at okio.AsyncTimeout$2.read(AsyncTimeout.java:211)
... 38 more

我不明白的是:为什么这在浏览器中能正常工作?我已经将timeouts设置为100seconds.我也尝试过使用其他HttpClient，但结果相同(我深信他们仍然使用相同的类).有人可以告诉我问题出在哪里吗?

What I do NOT understand is: why this works fine in the browser? I already set timeouts for 100seconds. I also tried with other HttpClients but with the same results (I believe deep down they use same classes anyways). Could anyone tell me where the problem lies, please?

我尝试了wget-工作，保存了一些HTML内容. curl返回:(52) Empty reply from server

I tried wget - worked, saved some HTML content. curl returned: (52) Empty reply from server

推荐答案

您必须在请求中使用User-Agent.这有效:

You have to use an User-Agent in your request. This works:

Request request = new Request.Builder().url("https://www.celebritycruises.com/").header("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0").build();

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