okhttp使用https忽略证书验证

   X509TrustManager xtm = new X509TrustManager() {
            @Override
            public void checkClientTrusted(X509Certificate[] chain, String authType) {
            }

            @Override
            public void checkServerTrusted(X509Certificate[] chain, String authType) {
            }

            @Override
            public X509Certificate[] getAcceptedIssuers() {
                X509Certificate[] x509Certificates = new X509Certificate[0];
                return x509Certificates;
            }
        };

        SSLContext sslContext = null;
        try {
            sslContext = SSLContext.getInstance("SSL");

            sslContext.init(null, new TrustManager[]{xtm}, new SecureRandom());

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (KeyManagementException e) {
            e.printStackTrace();
        }
        HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
            @Override
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .sslSocketFactory(sslContext.getSocketFactory())
                .hostnameVerifier(DO_NOT_VERIFY)
                .build();

之前在网上找到很多关于okhttp忽略https证书的代码，但在使用的时候都遇上了问题

E/AndroidRuntime( 9669): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxxx.android/com.xxxxActivity}: java.lang.NullPointerException: Attempt to get length of null array
E/AndroidRuntime( 9669):        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2623)
E/AndroidRuntime( 9669):        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2687)
E/AndroidRuntime( 9669):        at android.app.ActivityThread.access$800(ActivityThread.java:177)
E/AndroidRuntime( 9669):        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1557)
E/AndroidRuntime( 9669):        at android.os.Handler.dispatchMessage(Handler.java:111)
E/AndroidRuntime( 9669):        at android.os.Looper.loop(Looper.java:199)
E/AndroidRuntime( 9669):        at android.app.ActivityThread.main(ActivityThread.java:5755)
E/AndroidRuntime( 9669):        at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime( 9669):        at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime( 9669):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:982)
E/AndroidRuntime( 9669):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:777)
E/AndroidRuntime( 9669): Caused by: java.lang.NullPointerException: Attempt to get length of null array
E/AndroidRuntime( 9669):        at okhttp3.internal.tls.RealTrustRootIndex.<init>(RealTrustRootIndex.java:31)
E/AndroidRuntime( 9669):        at okhttp3.internal.Platform.trustRootIndex(Platform.java:100)
E/AndroidRuntime( 9669):        at okhttp3.internal.Platform$Android.trustRootIndex(Platform.java:249)
E/AndroidRuntime( 9669):        at okhttp3.OkHttpClient.<init>(OkHttpClient.java:189)
E/AndroidRuntime( 9669):        at okhttp3.OkHttpClient.<init>(OkHttpClient.java:60)
E/AndroidRuntime( 9669):        at okhttp3.OkHttpClient$Builder.build(OkHttpClient.java:718)

那是因为在

 public X509Certificate[] getAcceptedIssuers() {
                X509Certificate[] x509Certificates = new X509Certificate[0];
                return x509Certificates;
            }

这个方法中返回的值是null。