之前的执行方法：
String path = "E:/screenshot.png";
String cmd = "adb exec-out screencap -p > " + path;
Runtime.getRuntime.exec(cmd);
执行不成功
之后的执行方法
String path = "E:/screenshot.png";
String cmd = "adb exec-out screencap -p > " + path;
String [] command = {"cmd" , "/C" , cmd};
Process process = Runtime.getRuntime().exec(command);
执行成功
这样执行也可以，两个时间差不多
String path = "E:/screenshot.png";
String cmd = "adb exec-out screencap -p > " + path;
String [] command = {"cmd" , "/C" , cmd};
ProcessBuilder pb = new ProcessBuilder(command);
Process p = pb.start();
