glide加载https图片：https://futurestud.io/tutorials/glide-module-example-accepting-self-signed-https-certificates#0
OkHttp在4.4及以下不支持TLS协议的解决方法:
http://www.cnblogs.com/daquexian/p/5883585.html
在做超理论坛app的过程中，遇到许多用户反馈在他们的手机上客户端不能访问网络，我问了他们的手机型号和Android系统版本，全部是5.0以下的，之后我自己运行API19（4.4）的Android模拟器，也遇到了同样的错误。
错误信息如下：
javax.net.ssl.SSLHandshakeException: javax.net.ssl.SSLProtocolException: SSL handshake aborted: ssl=0x79f145b0: Failure in SSL library, usually a protocol error
error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
因为之前没有太多接触过网络协议，这个问题也确实很难搜到，所以我找了很久，才找到了原因：Android 4.4及以下的系统默认不支持TLS协议，所以遇到使用TLS协议的网站就无法访问了。
解决方法如下：创建一个SSLSocketFactoryCompat.java文件，内容如下：
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.security.GeneralSecurityException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.X509TrustManager;
public class SSLSocketFactoryCompat extends SSLSocketFactory {
private SSLSocketFactory defaultFactory;
// Android 5.0+ (API level21) provides reasonable default settings
// but it still allows SSLv3
// https://developer.android.com/about/versions/android-5.0-changes.html#ssl
static String protocols[] = null, cipherSuites[] = null;
static {
try {
SSLSocket socket = (SSLSocket)SSLSocketFactory.getDefault().createSocket();
if (socket != null) {
/* set reasonable protocol versions */
// - enable all supported protocols (enables TLSv1.1 and TLSv1.2 on Android <5.0)
// - remove all SSL versions (especially SSLv3) because they're insecure now
List protocols = new LinkedList<>();
for (String protocol : socket.getSupportedProtocols())
if (!protocol.toUpperCase().contains("SSL"))
protocols.add(protocol);
SSLSocketFactoryCompat.protocols = protocols.toArray(new String[protocols.size()]);
/* set up reasonable cipher suites */
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
// choose known secure cipher suites
List allowedCiphers = Arrays.asList(
// TLS 1.2
"TLS_RSA_WITH_AES_256_GCM_SHA384",
"TLS_RSA_WITH_AES_128_GCM_SHA256",
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",
"TLS_ECHDE_RSA_WITH_AES_128_GCM_SHA256",
// maximum interoperability
"TLS_RSA_WITH_3DES_EDE_CBC_SHA",
"TLS_RSA_WITH_AES_128_CBC_SHA",
// additionally
"TLS_RSA_WITH_AES_256_CBC_SHA",
"TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA",
"TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
"TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA",
"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA");
List availableCiphers = Arrays.asList(socket.getSupportedCipherSuites());
// take all allowed ciphers that are available and put them into preferredCiphers
HashSet preferredCiphers = new HashSet<>(allowedCiphers);
preferredCiphers.retainAll(availableCiphers);
/* For maximum security, preferredCiphers should *replace* enabled ciphers (thus disabling
* ciphers which are enabled by default, but have become unsecure), but I guess for
* the security level of DAVdroid and maximum compatibility, disabling of insecure
* ciphers should be a server-side task */
// add preferred ciphers to enabled ciphers
HashSet enabledCiphers = preferredCiphers;
enabledCiphers.addAll(new HashSet<>(Arrays.asList(socket.getEnabledCipherSuites())));
SSLSocketFactoryCompat.cipherSuites = enabledCiphers.toArray(new String[enabledCiphers.size()]);
}
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public SSLSocketFactoryCompat(X509TrustManager tm) {
try {
SSLContext sslContext = SSLContext.getInstance("TLS");
sslContext.init(null, (tm != null) ? new X509TrustManager[] { tm } : null, null);
defaultFactory = sslContext.getSocketFactory();
} catch (GeneralSecurityException e) {
throw new AssertionError(); // The system has no TLS. Just give up.
}
}
private void upgradeTLS(SSLSocket ssl) {
// Android 5.0+ (API level21) provides reasonable default settings
// but it still allows SSLv3
// https://developer.android.com/about/versions/android-5.0-changes.html#ssl
if (protocols != null) {
ssl.setEnabledProtocols(protocols);
}
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP && cipherSuites != null) {
ssl.setEnabledCipherSuites(cipherSuites);
}
}
@Override
public String[] getDefaultCipherSuites() {
return cipherSuites;
}
@Override
public String[] getSupportedCipherSuites() {
return cipherSuites;
}
@Override
public Socket createSocket(Socket s, String host, int port, boolean autoClose) throws IOException {
Socket ssl = defaultFactory.createSocket(s, host, port, autoClose);
if (ssl instanceof SSLSocket)
upgradeTLS((SSLSocket)ssl);
return ssl;
}
@Override
public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
Socket ssl = defaultFactory.createSocket(host, port);
if (ssl instanceof SSLSocket)
upgradeTLS((SSLSocket)ssl);
return ssl;
}
@Override
public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException, UnknownHostException {
Socket ssl = defaultFactory.createSocket(host, port, localHost, localPort);
if (ssl instanceof SSLSocket)
upgradeTLS((SSLSocket)ssl);
return ssl;
}
@Override
public Socket createSocket(InetAddress host, int port) throws IOException {
Socket ssl = defaultFactory.createSocket(host, port);
if (ssl instanceof SSLSocket)
upgradeTLS((SSLSocket)ssl);
return ssl;
}
@Override
public Socket createSocket(InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
Socket ssl = defaultFactory.createSocket(address, port, localAddress, localPort);
if (ssl instanceof SSLSocket)
upgradeTLS((SSLSocket)ssl);
return ssl;
}
}
在创建OkHttpClient的时候，添加这个SSLSocketFactory（我用单例模式来每次获取同一个全局的OkHttpClient，每个人的实现不一定一样，从我的代码里参考问题的解决方法就好）：
public synchronized static OkHttpClient getClient(){
if (okHttpClient == null) {
OkHttpClient.Builder builder = new OkHttpClient.Builder();
try {
// 自定义一个信任所有证书的TrustManager，添加SSLSocketFactory的时候要用到
final X509TrustManager trustAllCert =
new X509TrustManager() {
@Override
public void checkClientTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
}
@Override
public void checkServerTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
}
@Override
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return new java.security.cert.X509Certificate[]{};
}
};
final SSLSocketFactory sslSocketFactory = new SSLSocketFactoryCompat(trustAllCert);
builder.sslSocketFactory(sslSocketFactory, trustAllCert);
} catch (Exception e) {
throw new RuntimeException(e);
}
okHttpClient = builder.build();
}
return okHttpClient;
}
