java.net.httpurlconnection 不起作用

Question

我正在尝试在我的 android 应用程序中发出一个简单的 http 请求。

((HttpURLConnection) new URL("https://omg-a-site.org").openConnection()).getResponseCode();

我尝试使用 java.net.URL.getInputStream 和 java.net.URLConnection.getInputStream，但它不起作用。 难道我做错了什么？

Answer 1

你的代码正在做某事。 这是您的代码在“try”块内的try-catch。 如果发生任何 IOExceptions，catch 块将打印出异常文本中的任何内容。

try {
    ((HttpURLConnection) new URL("https://omg-a-site.org").openConnection()).getResponseCode();
} catch (IOException e) {
    e.printStackTrace();
}

该代码将产生下面的输出，看起来很合理——它找不到名为“omg-a-site.org”的主机：

java.net.UnknownHostException: omg-a-site.org
    at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:567)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
    at java.base/java.net.Socket.connect(Socket.java:633)
    at java.base/sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:299)
    at java.base/sun.security.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:174)
    at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:183)
    at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:498)
    at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:603)
    at java.base/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:266)
    at java.base/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:380)
    at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:189)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1242)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1128)
    at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:175)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1665)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1589)
    at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:529)
    at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:308)
    at a68.main(a68.java:8)