Android 判断root

private final static int kSystemRootStateUnknow = -1;
private final static int kSystemRootStateDisable = 0;
private final static int kSystemRootStateEnable = 1;
private static int systemRootState = kSystemRootStateUnknow;

public static boolean isRootSystem() {
if (systemRootState == kSystemRootStateEnable) {
return true;
} else if (systemRootState == kSystemRootStateDisable) {
return false;
}
File f = null;
final String kSuSearchPaths[] = { "/system/bin/", "/system/xbin/",
"/system/sbin/", "/sbin/", "/vendor/bin/" };
try {
for (int i = 0; i < kSuSearchPaths.length; i++) {
f = new File(kSuSearchPaths[i] + "su");
if (f != null && f.exists()) {
systemRootState = kSystemRootStateEnable;
return true;
}
}
} catch (Exception e) {
}
systemRootState = kSystemRootStateDisable;
return false;
}

public synchronized boolean getRootAhth()
{
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)
{
Log.d("*** DEBUG ***", "Unexpected error - Here is what I know: "
+ e.getMessage());
return false;
} finally
{
try
{
if (os != null)
{
os.close();
}
process.destroy();
} catch (Exception e)
{
e.printStackTrace();
}
}
}

//判断机器 Android是否已经root，即是否获取root权限
protected static boolean haveRoot()
{
int i = execRootCmdSilent("echo test"); //通过执行测试命令来检测
if (i != -1)  return true;
retrun false;
}