You can try downloading it through a browser instead of the AppStore, you can go to the Developer Center to download a DMG with your browser. It's in the Xcode 5 section. When you expand it, there is a link to the DMG:
You will need to be part of the Member Center to login. You can use the same page to download other things, such as documentation sets and the command line tools.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…