/**
     * 获取Https的证书
     * @param context Activity（fragment）的上下文
     * @return SSL的上下文对象
     */
    private static SSLContext getSSLContext(Context context) {
        SSLContext s_sSLContext = null;
        if (null != s_sSLContext) {
            return s_sSLContext;
        }

        CertificateFactory certificateFactory = null;

        InputStream inputStream = null;
        KeyStore keystore = null;
        String tmfAlgorithm = null;
        TrustManagerFactory trustManagerFactory = null;
        try {
            certificateFactory = CertificateFactory.getInstance("X.509");

            inputStream = context.getAssets().open("1781148__api.loan.agri-fintech.cn.pem");//这里导入SSL证书文件
            //            inputStream = context.getAssets().open("51p2b_server_bs.pem");//这里导入SSL证书文件

            Certificate ca = certificateFactory.generateCertificate(inputStream);

            keystore = KeyStore.getInstance(KeyStore.getDefaultType());
            keystore.load(null, null);
            keystore.setCertificateEntry("ca", ca);

            tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
            trustManagerFactory = TrustManagerFactory.getInstance(tmfAlgorithm);
            trustManagerFactory.init(keystore);

            // Create an SSLContext that uses our TrustManager
            s_sSLContext = SSLContext.getInstance("TLS");
            s_sSLContext.init(null, trustManagerFactory.getTrustManagers(), null);
            return s_sSLContext;
        } catch (CertificateException e) {
            e.printStackTrace();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (KeyStoreException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

public String httpGet(String httpUrl) {
        BufferedReader input = null;
        StringBuilder sb = null;
        URL url = null;
        HttpURLConnection con = null;
        try {
            url = new URL(httpUrl);
            try {
                SSLContext sslContext = getSSLContext(LoginActivity.this);
                HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());
                HttpsURLConnection https = (HttpsURLConnection) url.openConnection();
                HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {

                    @Override
                    public boolean verify(String hostname, SSLSession sslsession) {

                        if ("host".equals(hostname)) {//判断域名是否和证书域名相等
                            Log.i("tttt", "相等");
                            return true;
                        } else {
                            Log.i("tttt", "不相等");
                            return false;
                        }
                    }
                });
                if (url.getProtocol().toLowerCase().equals("https")) {//判断是http还是https
                    //https.setHostnameVerifier(DO_NOT_VERIFY);
                    con = https;
                } else {
                    con = (HttpURLConnection) url.openConnection();
                }
                input = new BufferedReader(new InputStreamReader(con.getInputStream()));
                sb = new StringBuilder();
                String s;
                while ((s = input.readLine()) != null) {
                    sb.append(s).append("\n");
                    Log.i("sss", sb+"");
                }

            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (MalformedURLException e1) {
            e1.printStackTrace();
        } finally {
            // close buffered
            if (input != null) {
                try {
                    input.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            // disconnecting releases the resources held by a connection so they may be closed or reused
            if (con != null) {
                con.disconnect();
            }
        }

        return sb == null ? null : sb.toString();
    }