解决Android&eclipse无法RunAs的问题

application不能运行，console显示

The connection to adb is down, and a severe error has occured.
You must restart adb and Eclipse.
Please ensure that adb is correctly located at 'XXXX' and can be executed.

我出错的原因是下载了2个adt包，环境变量和使用的eclipse地址不在一个包下。