最近碰到一个问题， 有朋友问android这边能不能拿到服务器下发的证书，意思就是 自签名证书的https接口，在请求的时候，也没有添加自签名证书进信任列表，直接去发https请求，按照正常https步骤去理解，服务器会返回一个证书，这个证书由于客户端没有添加进信任列表，会导致https请求失败，提示没有找到信任的证书。 朋友疑问： 在服务器返回证书的时候，能不能强行信任呢？
针对这个问题， 我在这边做了测试：
1，由ca签发的ssl证书，部署一个服务
不设置请求的SSLSocketFactory，直接进行https请求
验证结果：ok
2，自签名的ssl证书，部署一个服务
不设置请求的SSLSocketFactory，直接进行https请求
验证结果：error，报错信息 java.security.cert.CertPathValidatorException: Trust anchor for certification path not found，大体意思是没有找打信任的证书，也就是说这个证书没有被当前的请求对象所信任。
看报错信息是android系统已经封装好的证书校验规则。
但是如果不想本地预埋自签名证书，也不想让后台暴露证书下载的接口，该怎么办呢？
我这边提供一个比较简陋的方法，通过webview访问目标https地址，通过webview的onReceivedSslError方法，拿到SslError中的SslCertificate，然后再根据SslCertificate中的saveState方法获取Bundle，从bundle中拿到"x509-certificate"的字节数组，作为字节流读取流，通过通用的httpsutils，设置请求对象的sslsocketfactory。
代码如下：
package com.example.ajaxhttpsdemo; import android.content.Context;
import android.net.http.SslCertificate;
import android.net.http.SslError;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.webkit.SslErrorHandler;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient; import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate; import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager; public class HttpsGetSSLSocketFactory {
private static SslCertificate sslCertificate;
public static class SSLParams {
public SSLSocketFactory sSLSocketFactory;
public X509TrustManager trustManager;
} public interface Callback{
void onSuccess(SSLParams sslParams);
void onError(Exception e);
} public static class MySSLException extends Exception{
public MySSLException(String str) {
super(str);
}
} public static void getSslSocketFactoryOnMainThread(Context context, String httpsUrl, final Callback callback){
WebView webView = new WebView(context);
webView.setWebViewClient(new WebViewClient(){
@Override
public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
sslCertificate = error.getCertificate();
handler.proceed();
if (sslCertificate!=null){
Bundle bundle = SslCertificate.saveState(sslCertificate);
byte[] byteArray = bundle.getByteArray("x509-certificate");//从bundle中拿出写入的x509证书
// byte[] byteArray = "123456".getBytes();//测试错误证书
if (byteArray!=null && byteArray.length>0){
try {
callback.onSuccess(getSslSocketFactory(new ByteArrayInputStream(byteArray)));
} catch (Exception e) {
callback.onError(e);
}
}
}else {
callback.onError(new MySSLException("没有获取到服务器证书"));
}
}
});
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
webView.loadUrl(httpsUrl);
} private static SSLParams getSslSocketFactory(InputStream... certificates) throws Exception {
SSLParams sslParams = new SSLParams();
try {
TrustManager[] trustManagers = prepareTrustManager(certificates);
KeyManager[] keyManagers = prepareKeyManager(null, null);
SSLContext sslContext = SSLContext.getInstance("TLS");
X509TrustManager trustManager;
if (trustManagers != null) {
trustManager = new MyTrustManager(
chooseTrustManager(trustManagers));
} else {
throw new Exception("证书错误");
}
sslContext.init(keyManagers,
new TrustManager[]{trustManager}, null);
sslParams.sSLSocketFactory = sslContext.getSocketFactory();
sslParams.trustManager = trustManager;
return sslParams;
} catch (NoSuchAlgorithmException e) {
throw new AssertionError(e);
} catch (KeyManagementException e) {
throw new AssertionError(e);
} catch (KeyStoreException e) {
throw new AssertionError(e);
} catch (Exception e) {
throw e;
}
}
private static X509TrustManager chooseTrustManager(
TrustManager[] trustManagers) {
for (TrustManager trustManager : trustManagers) {
if (trustManager instanceof X509TrustManager) {
return (X509TrustManager) trustManager;
}
}
return null;
}
private static TrustManager[] prepareTrustManager(
InputStream... certificates) {
if (certificates == null || certificates.length <= 0)
return null;
try {
CertificateFactory certificateFactory = CertificateFactory
.getInstance("X.509");
KeyStore keyStore = KeyStore.getInstance(KeyStore
.getDefaultType());
keyStore.load(null);
int index = 0;
for (InputStream certificate : certificates) {
String certificateAlias = Integer.toString(index++);
keyStore.setCertificateEntry(certificateAlias,
certificateFactory.generateCertificate(certificate));
try {
if (certificate != null)
certificate.close();
} catch (IOException e) {
e.printStackTrace();
}
}
TrustManagerFactory trustManagerFactory;
trustManagerFactory = TrustManagerFactory
.getInstance(TrustManagerFactory.getDefaultAlgorithm());
trustManagerFactory.init(keyStore);
return trustManagerFactory.getTrustManagers();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private static KeyManager[] prepareKeyManager(InputStream bksFile,
String password) {
try {
if (bksFile == null || password == null)
return null;
KeyStore clientKeyStore = KeyStore.getInstance("PKCS12");
clientKeyStore.load(bksFile, password.toCharArray());
KeyManagerFactory keyManagerFactory = KeyManagerFactory
.getInstance(KeyManagerFactory.getDefaultAlgorithm());
keyManagerFactory.init(clientKeyStore, password.toCharArray());
return keyManagerFactory.getKeyManagers();
} catch (Exception e) {
e.printStackTrace();
}
return null;
} private static class MyTrustManager implements X509TrustManager {
private X509TrustManager defaultTrustManager;
private X509TrustManager localTrustManager; public MyTrustManager(X509TrustManager localTrustManager)
throws NoSuchAlgorithmException, KeyStoreException {
TrustManagerFactory var4 = TrustManagerFactory
.getInstance(TrustManagerFactory.getDefaultAlgorithm());
var4.init((KeyStore) null);
defaultTrustManager = chooseTrustManager(var4
.getTrustManagers());
this.localTrustManager = localTrustManager;
} @Override
public void checkClientTrusted(X509Certificate[] chain,
String authType) throws CertificateException {
} @Override
public void checkServerTrusted(X509Certificate[] chain,
String authType) throws CertificateException {
try {
defaultTrustManager.checkServerTrusted(chain, authType);
} catch (CertificateException ce) {
localTrustManager.checkServerTrusted(chain, authType);
}
} @Override
public X509Certificate[] getAcceptedIssuers() {
return new X509Certificate[0];
}
}
}
留作备用，有错误再更正