判断有没有联网

/**
     * 阿里公网:223.5.5.5
     *
     * @return 判断单个应用是个可以联网, 原理:ping网络
     */
    public static boolean isNetworkOnline() {

        Runtime runtime = Runtime.getRuntime();
        Process ipProcess = null;
        try {
            ipProcess = runtime.exec("ping -c 5 -w 4 223.5.5.5");
            InputStream input = ipProcess.getInputStream();

            BufferedReader in = new BufferedReader(new InputStreamReader(input));
            StringBuffer stringBuffer = new StringBuffer();
            String content = "";
            while ((content = in.readLine()) != null) {
                stringBuffer.append(content);
            }

            int exitValue = ipProcess.waitFor();
            if (exitValue == 0) {
                //WiFi连接，网络正常
                return true;
            } else {
                if (stringBuffer.indexOf("100% packet loss") != -1) {
                    XLog.showArgsInfo("网络丢包严重，判断为网络未连接");
                    return false;
                } else {
                    XLog.showArgsInfo("网络未丢包，判断为网络连接");
                    return true;
                }
            }
        } catch (IOException | InterruptedException e) {
            XLog.printExceptionInfo(e);
        } finally {
            if (ipProcess != null) {
                ipProcess.destroy();
            }
            runtime.gc();
        }
        return false;
    }