java运行shell命令，chmod 777 xxx，改变权限无效的解决的方法。

chmod 777 <span style="font-family: Arial, Helvetica, sans-serif;">/data/misc/123.sh"</span>

来改变权限，可是在java代码中运行这个命令时使用

Runtime.getRuntime().exec("chmod 777 /data/misc/123.sh")；

String[] command = new String[] {"/system/bin/sh","-c","chmod 777 /data/misc/123.sh"};
Runtime.getRuntime().exec(command);

最后通过实例化一个dataoutputstream对象，在这个对象的写字节方法里写命令才实现，代码例如以下：

String[] commands = new String[] { "/system/bin/sh", "-c",
			"chmod -R 777 /data/misc/123.sh" };
	Process process = null;
	DataOutputStream dataOutputStream = null;
try {

			process = Runtime.getRuntime().exec("su");
			dataOutputStream = new DataOutputStream(process.getOutputStream());
			int length = commands.length;
			for (int i = 0; i < length; i++) {
				dataOutputStream.writeBytes(commands[i] + "\n");
			}
			dataOutputStream.writeBytes("exit\n");
			dataOutputStream.flush();
			process.waitFor();
		} catch (Exception e) {

		} finally {
			try {
				if (dataOutputStream != null) {
					dataOutputStream.close();
				}
				process.destroy();
			} catch (Exception e) {
			}
		}