/*类1 这里继承了HttpURLConnection*/
abstract public class HttpUrlConnectionBase extends HttpURLConnection { protected HttpUrlConnectionBase(URL u) {
super(u);
}
.........
}类2 public class HTTP {
public HTTP(URL url){
HttpUrlConnectionBase httpUrlConnectionBase = (HttpUrlConnectionBase)url.openConnection(); //这里出错
...............
}
..........................}错误Exception in thread "main" java.lang.ClassCastException: sun.net.www.protocol.http.HttpURLConnection
请问,怎么解决,谢谢
abstract public class HttpUrlConnectionBase extends HttpURLConnection { protected HttpUrlConnectionBase(URL u) {
super(u);
}
.........
}类2 public class HTTP {
public HTTP(URL url){
HttpUrlConnectionBase httpUrlConnectionBase = (HttpUrlConnectionBase)url.openConnection(); //这里出错
...............
}
..........................}错误Exception in thread "main" java.lang.ClassCastException: sun.net.www.protocol.http.HttpURLConnection
请问,怎么解决,谢谢
HttpUrlConnection httpUrlConnection = (HttpUrlConnection)url.openConnection这样都不会出错
把范围缩小,则应该确保被缩小的对象是正确的对象