java - 网站关闭时会引发哪种异常？

Question

我正在使用 jsoup 从网站上抓取数据。我想知道当我抓取数据的网站关闭时会抛出哪个异常。
是 SocketException 或 NoHttpResponseException 还是其他异常？
我读到，当服务器收到请求但未能响应请求时，会引发 NoHttpResponseException ，这是正确的吗？

Answer 1

我测试了我们自己的网站，在关闭 Tomcat 后，我​​得到以下 java.net.SocketTimeoutException:

java.net.SocketTimeoutException: connect timed out
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:668)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:175)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:432)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:527)
    at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:264)
    at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:367)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1138)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1032)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:153)
    at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:563)
    at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:540)
    at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:227)
    at org.jsoup.helper.HttpConnection.get(HttpConnection.java:216)
    at testing.Test.main(Test.java:19)

这是我使用的代码:

public static void main(String[] args) {
    try {
        Document document = Jsoup.connect("https://example/folder").validateTLSCertificates(false).timeout(1000).get();
        System.out.println(document);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

NoHttpResponseException 似乎是一个 apache httpclient 异常(org.apache.commons.httpclient.NoHttpResponseException)。由于 Jsoup 没有 apache 依赖项，SocketTimeoutException 可能就是答案。