收藏：JavaMail使用SSL遇到安全证书问题

 业务需求又发生的改变，登录模块中要用邮箱去验证，于是试试企业邮件服务器发邮件，结果使用SSL遇到

PKIX：nable to find valid certification path to requested target

通过搜索和查询资料发现CSDN上一篇文章给出了一个关键性的步骤-获取安全证书。

  原文地址：

http://blog.csdn.net/faye0412/article/details/6883879

 获取安全证书的代码收藏下来：

/*
 * 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.
 */
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
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);
        }
    }
}

   生成证书的方法：

   1.编译InstallCert.java

   2.执行java InstallCert host password

    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

   4.重要：

     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！！！

    收藏一篇http://www.360doc.com/content/10/1221/10/3356862_79997919.shtml 基于SSL的JavaMail文章。