请注意，本博文发布于2011年6月，因此根据您阅读的时间，某些部分可能已过时。很遗憾，我无法始终保持这些文章的完全更新，以确保信息的准确性。
If you are trying, from your Android application through the Android emulator, to access an external service on the same computer (such as your own Google App Engine site) by using the host name localhost or the IP-address 127.0.0.1, you might get a java.net.ConnectException
java.net.ConnectException: localhost/127.0.0.1:8888 - Connection refused error - even though you can perfectly well access the service outside the Android application.
The reason why a ConnectException occurs is because "localhost" or "127.0.0.1" inside the Android emulator is the emulator's own loopback interface, meaning all request sent to the destination will be looped backed to the emulator and won't actually be sent to your local machine.
To by pass this, simply replace "localhost" with the IP-address "10.0.2.2", as this is a special address towards the real local host.
Done!
