我目前陷入困境，因为我发现ftp4j上的文档很轻。 根据这个： Document
我可以设置库以使用SSL证书进行连接。我遇到的问题是弄清楚图书馆将如何知道哪个SSL证书可以接受哪个SSL证书（如果是冒名顶替者）。 有帮助吗？ 谢谢！
编辑：我想知道如何导入SSL证书，并使该库仅连接到具有特定SSL证书的特定服务器。
答案 0 :(得分：1)
您可以使用Sun的InstallCert.java将要接受的证书保存在单独的商店中。然后在设置FTPClient时使用此单独的商店。
我在下面包含了一个版本的InstallCert.java，因为在甲骨文接手后，在互联网上找到它会越来越难......
/*
* 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);
}
}
}
在添加您提供的新证书之前，该代码会复制JRE提供的证书。如果您不想这样，而只是存储您的证书，则需要删除此部分：
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");
}
}
现在，当您拥有包含证书的文件时，可以使用此文件创建一个您提供给FTPClient的SSLSocketFactory。
您可以像这样创建某种证书管理器：
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.security.KeyStore;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
public class CertManager {
private static final char[] passphrase = "changeit".toCharArray();
private String rootPath;
private SSLSocketFactory factory;
private SavingTrustManager trustManager;
private KeyStore keyStore;
/**
* Creates a CertManager.
* @param rootPath Path to directory where the file 'jssecacerts' is located.
*/
public CertManager(String rootPath){
this.rootPath = rootPath;
}
/**
* Gets a SSLSocketFactory with the trusted certs.
* @return
* @throws Exception
*/
public SSLSocketFactory getSSLSocketFactory() throws Exception {
//Load trusted certs
File file = new File(rootPath+"jssecacerts");
System.out.println("Loading KeyStore " + file + "...");
InputStream in = new FileInputStream(file);
keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(in, passphrase);
in.close();
//Use these certs
SSLContext context = SSLContext.getInstance("TLS");
TrustManagerFactory tmf =
TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(keyStore);
X509TrustManager defaultTrustManager = (X509TrustManager)tmf.getTrustManagers()[0];
trustManager = new SavingTrustManager(defaultTrustManager);
context.init(null, new TrustManager[] {trustManager}, null);
factory = context.getSocketFactory();
return factory;
}
private static class SavingTrustManager implements X509TrustManager {
private final X509TrustManager tm;
private X509Certificate[] chain;
SavingTrustManager(X509TrustManager tm) {
this.tm = tm;
}
public X509Certificate[] getAcceptedIssuers() {
return tm.getAcceptedIssuers();
}
public void checkClientTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
this.chain = chain;
tm.checkClientTrusted(chain, authType);
}
public void checkServerTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
this.chain = chain;
tm.checkServerTrusted(chain, authType);
}
}
}
使用证书管理器获取您提供给FTPClient的SSLSocketFactory：
...
FTPClient client = new FTPClient();
CertManager certMan = new CertManager("");
SSLSocketFactory sslSocketFactory = null;
try{
sslSocketFactory = certMan.getSSLSocketFactory();
} catch (Exception e) {
e.printStackTrace();
}
client.setSSLSocketFactory(sslSocketFactory);
client.setSecurity(FTPClient.SECURITY_FTPS); // or client.setSecurity(FTPClient.SECURITY_FTPES);
...