Java 导致SunCertPathBuilderException的原因：无法找到请求目标的有效证书路径

我正在尝试运行一个非常简单的服务器/客户端ssl代码，其中包含一个自生成的密钥库文件。我得到了以下例外。 我确信代码没有问题，因为我可以在几周前运行它。但现在我得到了一个例外： 谁能告诉我怎么了

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:174)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1649)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:241)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:235)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1206)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:136)
    at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:593)
    at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:529)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:893)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1138)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:632)
    at com.sun.net.ssl.internal.ssl.AppOutputStream.write(AppOutputStream.java:59)
    at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:202)
    at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:272)
    at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:276)
    at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:122)
    at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:212)
    at java.io.BufferedWriter.flush(BufferedWriter.java:236)
    at EchoClient.main(EchoClient.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115)
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:323)
    at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:217)
    at sun.security.validator.Validator.validate(Validator.java:218)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:126)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:209)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:249)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1185)
    ... 19 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:174)
    at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:238)
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:318)
    ... 25 more

以下是我的代码：

public
class EchoServer {
    public static void main(String[] arstring) {
        System.setProperty("javax.net.ssl.keyStore", "c:\\projects\\sandbox\\SSLServer\\mySrvKeyStore");
        System.setProperty("javax.net.ssl.keyStorePassword", "delphi");
        try {
            SSLServerSocketFactory sslserversocketfactory =
                    (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();
            SSLServerSocket sslserversocket =
                    (SSLServerSocket) sslserversocketfactory.createServerSocket(9999);
            SSLSocket sslsocket = (SSLSocket) sslserversocket.accept();

            InputStream inputstream = sslsocket.getInputStream();
            InputStreamReader inputstreamreader = new InputStreamReader(inputstream);
            BufferedReader bufferedreader = new BufferedReader(inputstreamreader);

            String string = null;
            while ((string = bufferedreader.readLine()) != null) {
                System.out.println(string);
                System.out.flush();
            }
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }
}


public
class EchoClient {
    public static void main(String[] arstring) {
        System.setProperty("javax.net.ssl.keyStore", "c:\\projects\\sandbox\\SSLClient\\mySrvKeyStore");
        System.setProperty("javax.net.ssl.keyStorePassword", "delphi");
        try {
            SSLSocketFactory sslsocketfactory = (SSLSocketFactory) SSLSocketFactory.getDefault();
            SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket("localhost", 9999);

            InputStream inputstream = System.in;
            InputStreamReader inputstreamreader = new InputStreamReader(inputstream);
            BufferedReader bufferedreader = new BufferedReader(inputstreamreader);

            OutputStream outputstream = sslsocket.getOutputStream();
            OutputStreamWriter outputstreamwriter = new OutputStreamWriter(outputstream);
            BufferedWriter bufferedwriter = new BufferedWriter(outputstreamwriter);

            String string = null;
            while ((string = bufferedreader.readLine()) != null) {
                bufferedwriter.write(string + '\n');
                bufferedwriter.flush();
            }
        } catch (Exception exception) {
            exception.printStackTrace();
        }

    }
}

---

这可能意味着您使用的是自签名证书，它不“受信任”。对其进行了讨论。该链接解释了如何将证书添加到密钥存储中（如果您确实想这样做）。

客户端需要知道如何与服务器的证书建立信任关系。这意味着客户端可以找到一个证书颁发机构或证书颁发机构链，负责对服务器提供的证书进行签名。默认情况下，这是隐藏在java运行时目录中的cacerts文件，但在您的情况下可能不起作用

尝试将此属性javax.net.ssl.trustStore设置为持有签署服务器证书的证书的密钥库。如果它是自签名的，则基本上是告诉客户端您信任服务器来识别自己