java getLocalCertificates（）返回null

Question

我正在尝试编写一个简单的ssl服务器socket和客户端socket程序。首先我得到一些真正的证书，然后我使用第一个代码为它生成密钥库。然后我编写了服务器和客户机代码，以便我的服务器使用该密钥库作为服务器证书，但在连接和会话期间不发送证书。getLocalCertificates（）仅返回null 我的密钥库生成代码：

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.security.KeyStore;
import java.security.cert.CertPath;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.List;

public class MainClass {
    public static void main(String args[]) throws Exception {
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        List mylist = new ArrayList();

            FileInputStream in = new FileInputStream("C:\\Users\\nima\\Downloads\\72315359_example.com.cert");
            Certificate cr = cf.generateCertificate(in);
            mylist.add(cr);

        CertPath cp = cf.generateCertPath(mylist);
        System.out.println(cp);

        KeyStore ks = KeyStore.getInstance("JKS");
        ks.load(null, null);
        List cplist = cp.getCertificates();
        Object[] o = cplist.toArray();
        for (int i = 0; i < o.length; i++) {
            X509Certificate c = (X509Certificate) o[i];
            ks.setCertificateEntry("my" + i, c);
        }
        FileOutputStream output = new FileOutputStream("C:\\Users\\nima\\Downloads\\test.dat");
        ks.store(output, "mypass".toCharArray());
        output.close();

    }
}

我的服务器代码：

import java.io.PrintStream;
import java.math.BigInteger;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

import javax.net.ssl.SSLServerSocketFactory;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;

public class MainClass {
    public static void main(String args[]) throws Exception {
        System.setProperty("javax.net.ssl.keyStore", "C:\\Users\\nima\\Downloads\\test.dat");
        System.setProperty("javax.net.ssl.keyStorePassword", "mypass");

        SSLServerSocketFactory ssf = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();
        ServerSocket ss = ssf.createServerSocket(5432);
        while (true) {
            Socket s = ss.accept();
            SSLSession session = ((SSLSocket) s).getSession();
            Certificate[] cchain2 = session.getLocalCertificates();
            for (int i = 0; i < cchain2.length; i++) {
                System.out.println(((X509Certificate) cchain2[i]).getSubjectDN());
            }
            System.out.println("Peer host is " + session.getPeerHost());
            System.out.println("Cipher is " + session.getCipherSuite());
            System.out.println("Protocol is " + session.getProtocol());
            System.out.println("ID is " + new BigInteger(session.getId()));
            System.out.println("Session created in " + session.getCreationTime());
            System.out.println("Session accessed in " + session.getLastAccessedTime());

            PrintStream out = new PrintStream(s.getOutputStream());
            out.println("Hi");
            out.close();
            s.close();
        }

    }
}

我的客户代码：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.net.Socket;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;

import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;

public class MainClass {
    public static void main(String args[]) throws Exception {
        System.setProperty("javax.net.ssl.trustStore", "C:\\Users\\nima\\Downloads\\test.dat");

        SSLSocketFactory ssf = (SSLSocketFactory) SSLSocketFactory.getDefault();
        Socket s = ssf.createSocket("127.0.0.1", 5432);

        SSLSession session = ((SSLSocket) s).getSession();
        Certificate[] cchain = session.getPeerCertificates();
        System.out.println("The Certificates used by peer");
        for (int i = 0; i < cchain.length; i++) {
            System.out.println(((X509Certificate) cchain[i]).getSubjectDN());
        }
        System.out.println("Peer host is " + session.getPeerHost());
        System.out.println("Cipher is " + session.getCipherSuite());
        System.out.println("Protocol is " + session.getProtocol());
        System.out.println("ID is " + new BigInteger(session.getId()));
        System.out.println("Session created in " + session.getCreationTime());
        System.out.println("Session accessed in " + session.getLastAccessedTime());

        BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
        String x = in.readLine();
        System.out.println(x);
        in.close();

    }
}

我的服务器代码来自here，在服务器端和客户端，我从getLocalCertificates获得null。也有可能我所有的代码都是错误的

Answer 1

（摘自评论，略加扩展）

如果在握手完成之前调用了SSLSocket.getSession()，它会尝试执行此操作，但如果握手失败getSession()则会吞下异常并仅返回一个“nullSession”对象，该对象没有实际会话对象所需的数据。要么（1）设置syspropjavax.net.debug=ssl（在启动时，通常在命令行上使用-D），查看它的日志，看看你的握手有什么问题；要么（2）显式调用((SSLSocket)s).startHandshake()（不管名称如何，它实际上运行握手完成，成功与否），看看它抛出了什么

特别是，如果您使用由显示的第一个代码创建的密钥库文件，该文件仅包含证书（trustedCertEntry），而不是SSL/TLS服务器使用任何通用和默认启用套件所必需和必需的privateKeyEntry（具有privatekey和证书/链）；这一错误通常会表现为“无密码[suite]通用”或“无密码[suite]重叠”的握手失败，这有点令人困惑

第二部分（没有私钥的SSL/TLS服务器不工作）已经被询问和回答了很多次，但我不记得还有任何重复也包括“getSession掩盖错误”部分