本文主要讨论的是java开发https请求ssl不受信任的解决方法，具体分析及实现代码如下。
在java代码中请求https链接的时候，可能会报下面这个错误
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
原因是没有证书。在浏览器中直接使用url访问是可以的，应该是浏览器之前就保存过对应的.cer证书。
解决方法有两种，从目标机器获得有效证书或者忽略证书信任问题。
一、获得目标机器有效证书
1、编译安装证书程序 javac InstallCert.java（代码如下）
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/* * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Sun Microsystems nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *//** * http://blogs.sun.com/andreas/resource/InstallCert.java * Use: * java InstallCert hostname * Example: *% java InstallCert ecc.fedora.redhat.com */import javax.net.ssl.*;import java.io.*;import java.security.KeyStore;import java.security.MessageDigest;import java.security.cert.CertificateException;import java.security.cert.X509Certificate;/** * Class used to add the server's certificate to the KeyStore * with your trusted certificates. */public class InstallCert { public static void main(String[] args) throws Exception { String host; int port; char[] passphrase; if ((args.length == 1) || (args.length == 2)) { String[] c = args[0].split(":"); host = c[0]; port = (c.length == 1) ? 443 : Integer.parseint(c[1]); String p = (args.length == 1) ? "changeit" : args[1]; passphrase = p.toCharArray(); } else { System.out.println("Usage: java InstallCert <host>[:port] [passphrase]"); return; } File file = new File("jssecacerts"); if (file.isFile() == false) { char SEP = File.separatorchar; File dir = new File(System.getProperty("java.home") + SEP + "lib" + SEP + "security"); file = new File(dir, "jssecacerts"); if (file.isFile() == false) { file = new File(dir, "cacerts"); } } System.out.println("Loading KeyStore " + file + "..."); InputStream in = new FileInputStream(file); KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType()); ks.load(in, passphrase); in.close(); SSLContext context = SSLContext.getInstance("TLS"); TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm()); tmf.init(ks); X509TrustManager defaultTrustManager = (X509TrustManager) tmf.getTrustManagers()[0]; SavingTrustManager tm = new SavingTrustManager(defaultTrustManager); context.init(null, new TrustManager[]{ tm } , null); SSLSocketFactory factory = context.getSocketFactory(); System.out.println("Opening connection to " + host + ":" + port + "..."); SSLSocket socket = (SSLSocket) factory.createSocket(host, port); socket.setSoTimeout(10000); try { System.out.println("Starting SSL handshake..."); socket.startHandshake(); socket.close(); System.out.println(); System.out.println("No errors, certificate is already trusted"); } catch (SSLException e) { System.out.println(); e.printStackTrace(System.out); } X509Certificate[] chain = tm.chain; if (chain == null) { System.out.println("Could not obtain server certificate chain"); return; } BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); System.out.println(); System.out.println("Server sent " + chain.length + " certificate(s):"); System.out.println(); MessageDigest sha1 = MessageDigest.getInstance("SHA1"); MessageDigest md5 = MessageDigest.getInstance("MD5"); for (int i = 0; i < chain.length; i++) { X509Certificate cert = chain[i]; System.out.println (" " + (i + 1) + " Subject " + cert.getSubjectDN()); System.out.println(" Issuer " + cert.getIssuerDN()); sha1.update(cert.getEncoded()); System.out.println(" sha1 " + toHexString(sha1.digest())); md5.update(cert.getEncoded()); System.out.println(" md5 " + toHexString(md5.digest())); System.out.println(); } System.out.println("Enter certificate to add to trusted keystore or 'q' to quit: [1]"); String line = reader.readLine().trim(); int k; try { k = (line.length() == 0) ? 0 : Integer.parseint(line) - 1; } catch (NumberFormatException e) { System.out.println("KeyStore not changed"); return; } X509Certificate cert = chain[k]; String alias = host + "-" + (k + 1); ks.setCertificateEntry(alias, cert); OutputStream out = new FileOutputStream("jssecacerts"); ks.store(out, passphrase); out.close(); System.out.println(); System.out.println(cert); System.out.println(); System.out.println ("Added certificate to keystore 'jssecacerts' using alias '" + alias + "'"); } private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray(); private static String toHexString(byte[] bytes) { StringBuilder sb = new StringBuilder(bytes.length * 3); for (int b : bytes) { b &= 0xff; sb.append(HEXDIGITS[b >> 4]); sb.append(HEXDIGITS[b & 15]); sb.append(' '); } return sb.toString(); } private static class SavingTrustManager implements X509TrustManager { private final X509TrustManager tm; private X509Certificate[] chain; SavingTrustManager(X509TrustManager tm) { this.tm = tm; } public X509Certificate[] getAcceptedIssuers() { throw new UnsupportedOperationException(); } public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException { throw new UnsupportedOperationException(); } public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException { this.chain = chain; tm.checkServerTrusted(chain, authType); } }} |
2、运行安装证书程序生成证书
java InstallCert my.hoolai.com
例如：java InstalCert smtp.zhangsan.com:465 admin
如果不加参数password和host的端口号，上面的获取证书程序中默认给的端口号是：443，密码是:changeit
3、根据运行提示信息，输入1，回车，在当前目录下生成名为： jssecacerts 的证书
将证书放置到$JAVA_HOME/jre/lib/security目录下， 切记该JDK的jre是工程所用的环境！！！
或者：
System.setProperty("javax.net.ssl.trustStore", "你的jssecacerts证书路径");
可以更改密码，在security目录下运行命令
keytool -storepasswd -new xxxcom -keystore cacerts
就可以修改密码，修改后使用命令
keytool -list -v -keystore cacerts
查看文件的信息，会提示需要密码才能查看，如果输入密码与修改后的密码匹配，说明修改成功了。
PS：至此这种方式可以成功使用ssl了，另外再补充一下，根据刚才生成的文件jssecacerts，可以生成cer文件，
命令如下
keytool -export -alias xxx.com-1 -keystore jssecacerts -rfc -file xxx.cer
如上，之前的工具类中默认命名别名是加上"-1"。使用InstallCert设置的密码需要跟cacerts文件中的密码一致，
如果修改过密码，就需要修改InstallCert类中对应的密码字符串，否则会有下面这个异常：
java.security.UnrecoverableKeyException: Password verification failed
二、忽略证书信任问题
源码：http://mengyang.iteye.com/blog/575671
一定要注意需要在connection创建之前调用文章里所述的方法，像这个样子：
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trustAllHttpsCertificates();HostnameVerifier hv = new HostnameVerifier() { public boolean verify(String urlHostName, SSLSession session) { return true; } };HttpsURLConnection.setDefaultHostnameVerifier(hv);connection = (HttpURLConnection) url.openConnection(); |
好吧，两种方法都试过有效。
总结
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原文链接：http://blog.csdn.net/Zhaky/article/details/50923411
