呼叫https介面時報錯：PKIX path building failed 的問題

PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: 

unable to find valid certification path to requested target

這是缺少安全證照時出現的異常，解決方案就是將你要訪問的webservice的安全認證證照匯入到客戶端即可。以下是獲取安全證照的一種方法

1，寫一個程式專門獲取安全證照，參考InstallCert.java:

/*
 * 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.*;
import java.net.URL;

import java.security.*;
import java.security.cert.*;

import javax.net.ssl.*;

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.執行 java InstallCert hostname 比如

java InstallCert ecc.fedora.redhat.com

會看到如下資訊：

java InstallCert ecc.fedora.redhat.com
Loading KeyStore /usr/jdk/instances/jdk1.5.0/jre/lib/security/cacerts...
Opening connection to ecc.fedora.redhat.com:443...
Starting SSL handshake...

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
	at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:150)
	at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1476)
	at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:174)
	at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:168)
	at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:846)
	at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:106)
	at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:495)
	at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:433)
	at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:815)
	at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1025)
	at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1038)
	at InstallCert.main(InstallCert.java:63)
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:221)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:145)
	at sun.security.validator.Validator.validate(Validator.java:203)
	at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:172)
	at InstallCert$SavingTrustManager.checkServerTrusted(InstallCert.java:158)
	at com.sun.net.ssl.internal.ssl.JsseX509TrustManager.checkServerTrusted(SSLContextImpl.java:320)
	at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:839)
	... 7 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:236)
	at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:194)
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:216)
	... 13 more

Server sent 2 certificate(s):

 1 Subject CN=ecc.fedora.redhat.com, O=example.com, C=US
   Issuer  CN=Certificate Shack, O=example.com, C=US
   sha1    2e 7f 76 9b 52 91 09 2e 5d 8f 6b 61 39 2d 5e 06 e4 d8 e9 c7 
   md5     dd d1 a8 03 d7 6c 4b 11 a7 3d 74 28 89 d0 67 54 

 2 Subject CN=Certificate Shack, O=example.com, C=US
   Issuer  CN=Certificate Shack, O=example.com, C=US
   sha1    fb 58 a7 03 c4 4e 3b 0e e3 2c 40 2f 87 64 13 4d df e1 a1 a6 
   md5     72 a0 95 43 7e 41 88 18 ae 2f 6d 98 01 2c 89 68 

Enter certificate to add to trusted keystore or 'q' to quit: [1]

3.輸入1，然後直接回車，會在相應的目錄下產生一個名為‘jssecacerts’的證照。將證照copy到$JAVA_HOME/jre/lib/security目錄下，或者通過以下方式

System.setProperty("javax.net.ssl.trustStore", "D:\\UTA\\DOC_E_Health_XML\\Keystore\\jssecacerts");

注意：要重新啟動你的應用伺服器，因是靜態載入，證照才能被運用上。