判断是否root了

public static synchronized boolean isRoot()
{
Process process = null;
DataOutputStream os = null;
try
{
process = Runtime.getRuntime().exec("su");
os = new DataOutputStream(process.getOutputStream());
os.writeBytes("exit\n");
os.flush();
int exitValue = process.waitFor();
if(exitValue == 0)
{
return true;
} else
{
return false;
}
} catch (Exception e)
{
return false;
} finally
{
try
{
if(os != null)
{
os.close();
}
process.destroy();
} catch (Exception e)
{
e.printStackTrace();
}
}
}