解决ADB server didn't ACK问题
之前运行eclipse执行android应用都没问题，今天突然出问题了，控制台报错：
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 'D:\android-2.2-windows\tools\adb.exe' and can be executed.
在命令行下运行 adb start-server
errors:
* daemon not running. starting it now *
ADB server didn't ACK
* failed to start daemon *
已经确认adb.exe的路径没有问题，重启了几次模拟器和eclipse还是不行，上网查了下资料~
解决办法：
（1）查看任务管理器，关闭所有adb.exe
（2）重启eclipse即可
