android HTTPURLConnection解决不能访问HTTPs请求

详细分析Android及Java中访问https请求exception(SSLHandshakeException, SSLPeerUnverifiedException)的原因及解决方法。

1、现象

用Android(或Java)测试程序访问下面两个链接。

https链接一：web服务器为jetty，后台语言为java。

https链接二：web服务器为nginx，后台语言为php。

链接一能正常访问，访问链接二报异常，且用HttpURLConnection和apache的HttpClient两种不同的api访问异常信息不同，具体如下：

(1) 用HttpURLConnection访问，测试代码如下：

HttpURLConnection访问https

Java

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public static String httpGet(String httpUrl) { BufferedReader input = null; StringBuilder sb = null; URL url = null; HttpURLConnection con = null; try { url = new URL(httpUrl); try { 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"); } } 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();}

异常信息为：

1	javax.net.ssl.SSLPeerUnverifiedException:Nopeercertificate

(2) 用apache的HttpClient访问，测试代码如下：

HttpClient访问https

Java

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public static String httpGet(String httpUrl) { HttpClient httpClient = new HttpClient(); GetMethod httpGet = new GetMethod(httpUrl); try { if (httpClient.executeMethod(httpGet) != HttpStatus.SC_OK) { // System.err.println("HttpGet Method failed: " + httpGet.getStatusLine()); return null; } return httpGet.getResponseBodyAsString(); } catch (Exception e) { e.printStackTrace(); } finally { httpGet.releaseConnection(); httpClient = null; } return null;}

异常信息为：

1	javax.net.ssl.SSLHandshakeException:sun.security.validator.ValidatorException:PKIXpathbuildingfailed:sun.security.provider.certpath.SunCertPathBuilderException:unabletofindvalidcertificationpathtorequestedtarget

2、原因分析

需要快速寻求答案的可直接看第3部分 解决方式，这部分详细分析原因。

google发现stackoverflow上不少人反应，twitter和新浪微博的api也会报这个异常，不少人反映客户端需要导入证书，其实大可不必，如果要导证书的话，用户不得哭了。。

从上面的情况可以看出，用jetty做为容器是能正常访问的，只是当容器为nginx时才会异常。

配合后台开发调试了很久，开始以为是cipher suite的问题，为此特地把

ssl_ciphers EDH-RSA-DES-CBC3-SHA;

加入了nginx的配置中，后来发现依然无效。stackoverflow发现，如下代码是能正常访问上面异常的https url

HttpURLConnection访问https并相信所有证书

Java

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public static String httpGet(String httpUrl) { BufferedReader input = null; StringBuilder sb = null; URL url = null; HttpURLConnection con = null; try { url = new URL(httpUrl); try { // trust all hosts trustAllHosts(); HttpsURLConnection https = (HttpsURLConnection)url.openConnection(); if (url.getProtocol().toLowerCase().equals("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"); } } 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();} final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() { public boolean verify(String hostname, SSLSession session) { return true; } }; /** * Trust every server - dont check for any certificate */private static void trustAllHosts() { final String TAG = "trustAllHosts"; // Create a trust manager that does not validate certificate chains TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() { public java.security.cert.X509Certificate[] getAcceptedIssuers() { return new java.security.cert.X509Certificate[] {}; } public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException { Log.i(TAG, "checkClientTrusted"); } public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException { Log.i(TAG, "checkServerTrusted"); } } }; // Install the all-trusting trust manager try { SSLContext sc = SSLContext.getInstance("TLS"); sc.init(null, trustAllCerts, new java.security.SecureRandom()); HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory()); } catch (Exception e) { e.printStackTrace(); }}

可以看出其中与之前的HttpsURLConnection测试代码主要的不同就是加入了

1	trustAllHosts();

和

1	https.setHostnameVerifier(DO_NOT_VERIFY);

表示相信所有证书，并且所有host name验证返回true，这样就能定位到之前的异常是证书验证不通过的问题了。

在上面checkServerTrusted函数中添加断点，查看X509Certificate[] chain的值，即证书信息，发现访问两个不同链接X509Certificate[] chain值有所区别，nginx传过来证书信息缺少了startssl 的ca证书，证书如下：



至此原因大白：

android的证书库里已经带了startssl
ca证书，而nginx默认不带startssl ca证书，这样android端访问nginx为容器的https url校验就会失败，jetty默认带startssl ca证书，所以正常。

PS：后来对windows和mac下java访问https也做了测试，发现mac上的jdk缺省不带startssl ca证书所以能访问通过，而加上startssl ca证书后同android一样访问不通过。而windows上的jdk缺省带startssl ca证书同android一样访问失败。

3、解决方式

上面的分析中已经介绍了一种解决方法即客户端相信所有证书，不过这种方式只是规避了问题，同时也给客户端带来了风险，比较合适的解决方式是为nginx添加startssl
ca证书，添加方法如下：

First, use the StartSSL™ Control Panel to create a private key and certificate and transfer them to your server. Then execute the following steps (if you use a class 2 certificate replace class1 by class2 in the instructions below):

Decrypt the private key by using the password you entered when you created your key:

openssl
rsa -in ssl.key -out /etc/nginx/conf/ssl.key

Alternatively you can also use the Tool Box decryption tool of your StartSSL™ account.

Protect your key from prying eyes:

chmod
600 /etc/nginx/conf/ssl.key

Fetch the Root CA and Class 1 Intermediate Server CA certificates:

wget http://www.startssl.com/certs/ca.pem

wget http://www.startssl.com/certs/sub.class1.server.ca.pem

Create a unified certificate from your certificate and the CA certificates:

cat
ssl.crt sub.class1.server.ca.pem ca.pem > /etc/nginx/conf/ssl-unified.crt

Configure your nginx server to use the new key and certificate (in the global settings or a server section):

ssl
on;

ssl_certificate /etc/nginx/conf/ssl-unified.crt;

ssl_certificate_key /etc/nginx/conf/ssl.key;

Tell nginx to reload its configuration:

killall
-HUP nginx

也可以直接访问install startssl on nginx.

参考:http://blog.csdn.net/jianglili611/article/details/46290431