给安卓OKHTTP库添加HTTPS证书验证

码字辛苦！转载请注明出处！

网传的使用sslSocketFactory方法的验证方式已经过时了，因为使用这个方法会使用反射机制寻找X509信任管理类，消耗了不必要的性能。

新的方法名称依然叫sslSocketFactory，但是会传入信任管理类数组中的第一条，这个博主已在OKHTTP的GITHUB样例源码中求证，请各位放心使用~

这里放上博主封装的工具，支持传入字符串证书、传入RAW资源目录下的证书、批量添加证书和信任所有证书的功能。

使用方法：

            //信任所有证书
            HTTPSCerUtils.setTrustAllCertificate(okHttpBuilder);
 
            //信任raw资源目录下的证书
            HTTPSCerUtils.setCertificate(context, okHttpBuilder, R.raw.rootca);
 
            //传入证书字符串
            HTTPSCerUtils.setCertificate(context,okHttpBuilder,"!@$#@!$@#^@^#!");

工具类：

import android.content.Context;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.security.KeyStore;
import java.security.SecureRandom;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

import okhttp3.OkHttpClient;

public class HTTPSCerUtils {

    //信任所有证书
    public static void setTrustAllCertificate(OkHttpClient.Builder okHttpClientBuilder) {
        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            X509TrustManager trustAllManager = new X509TrustManager() {
                @Override
                public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {

                }

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

                }

                @Override
                public X509Certificate[] getAcceptedIssuers() {
                    return new X509Certificate[0];
                }
            };
            sc.init(null, new TrustManager[]{trustAllManager}, new SecureRandom());
            okHttpClientBuilder.sslSocketFactory(sc.getSocketFactory(), trustAllManager);
            //如果需要兼容安卓5.0以下，可以使用这句
            //okHttpClientBuilder.sslSocketFactory(new TLSSocketFactory(), trustAllManager);
            okHttpClientBuilder.hostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //只信任指定证书（传入字符串）
    public static void setCertificate(Context context, OkHttpClient.Builder okHttpClientBuilder, String cerStr) {
        try {
            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(cerStr.getBytes());
            Certificate ca = certificateFactory.generateCertificate(byteArrayInputStream);

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

            byteArrayInputStream.close();

            TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keyStore);

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, tmf.getTrustManagers(), new SecureRandom());
            okHttpClientBuilder.sslSocketFactory(sslContext.getSocketFactory(), (X509TrustManager) tmf.getTrustManagers()[0]);
            okHttpClientBuilder.hostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //只信任指定证书（传入raw资源ID）
    public static void setCertificate(Context context, OkHttpClient.Builder okHttpClientBuilder, int cerResID) {
        try {
            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            InputStream inputStream = context.getResources().openRawResource(cerResID);
            Certificate ca = certificateFactory.generateCertificate(inputStream);

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

            inputStream.close();

            TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keyStore);

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, tmf.getTrustManagers(), new SecureRandom());
            okHttpClientBuilder.sslSocketFactory(sslContext.getSocketFactory(), (X509TrustManager) tmf.getTrustManagers()[0]);
            okHttpClientBuilder.hostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //批量信任证书
    public static void setCertificates(Context context, OkHttpClient.Builder okHttpClientBuilder, int... cerResIDs) {
        try {
            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");

            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keyStore.load(null, null);
            for (int i = 0; i < cerResIDs.length; i++) {
                Certificate ca = certificateFactory.generateCertificate(context.getResources().openRawResource(cerResIDs[i]));
                keyStore.setCertificateEntry("ca" + i, ca);
            }

            TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keyStore);

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, tmf.getTrustManagers(), new SecureRandom());
            okHttpClientBuilder.sslSocketFactory(sslContext.getSocketFactory(), (X509TrustManager) tmf.getTrustManagers()[0]);
            okHttpClientBuilder.hostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}