启动和关掉 adb服务器
当你启动 Android服务器时，adb服务器也就会一起启动。当你无法确定 adb服务器是否已启动？可以用“adb start-server”命令来启动 adb服务器，如果已启动就不做任何事，尚未启动就会直接启动 adb服务器。若你不想继续进行调试监控，则可以用“ adb kill-server”命令来关掉 adb服务器。
E:\Android\android-sdk-windows\platform-tools>adb start-server
E:\Android\android-sdk-windows\platform-tools>adb kill-server
E:\Android\android-sdk-windows\platform-tools>adb devices
* daemon not running. starting it now on port 5037 *
could not read ok from ADB Server, error = 109
* failed to start daemon *
error: cannot connect to daemon
E:\Android\android-sdk-windows\platform-tools>adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
2CBE000400000001 device
android adb shell:unknown host service
我们在Windows DOS窗口中输入adb shell后，会出现如下错误： adb server is out of date. killing... ADB server didn't ACK * failed to start daemon * error: unknown host service ，出现这问题是因为你的电脑上安装了豌豆夹造成的，只需打开“任务管理器”，找到'wandoujia_helper.exe'，把这个进行终止掉就可以，
