java.lang.ClassCastException: libcore.net.http.HttpURLConnectionImpl cannot be cast to javax.net.ssl.HttpsURLConnection
1.在虛擬器里運行時老是溢出這個異常，把自己的url從“localhost：(端口號)”改成“10.0.2.2: (端口號)”還是沒用；
2.后來Google之，找到問題所在，要把’http’改成‘https’;(s代表security)
源代碼：
1: HttpsURLConnection conn = null;
2: URL url = new URL(urlstring);
3: conn = (HttpsURLConnection) url.openConnection(); // exception here.
logcat中爆出的異常是長這樣的：
1: 06-20 15:58:05.311: E/FNF(30286): java.lang.ClassCastException: libcore.net.http.HttpURLConnectionImpl cannot be cast to javax.net.ssl.HttpsURLConnection
問題在我的import中：
1: import javax.net.ssl.HttpsURLConnection;
解釋：
SSL(Secure Sockets Layer 安全套接層)
HTTPS（Secure Hypertext Transfer Protocol）安全超文本傳輸協議
這兩者是相互對應的。