javax.net.ssl.SSLHandshakeException:PKIX path building failed解决方法的代码

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);    }    }}