The source of this error on my Apache 2.4 instance (using a Comodo wildcard certificate) was an incomplete path to the SHA-1 signed root certificate. There were multiple chains in the issued certificate, and the chain leading to a SHA-1 root certificate was missing an intermediate certificate. Modern browsers know how to handle this, but Java 7 doesn't handle it by default (although there are some convoluted ways to accomplish this in code). The result is error messages that look identical to the case of self-signed certificates:

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:196)
    at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:268)
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:380)
    ... 22 more

In this case, the "unable to find valid certification path to requested target" message is being produced due to the missing intermediate certificate. You can check which certificate is missing using SSL Labs test against the server. Once you find the appropriate certificate, download it and (if the server is under your control) add it to the certificate bundle. Alternatively, you can import the missing certificate locally. Accommodating this issue on the server is a more general solution to the problem.

有很多方法可以解决这个问题…

一种方法是在keystore文件中设置TrustStore证书，并将其放在应用程序的路径中，并在main方法中设置这些系统属性:

public static void main(String[] args) {
  System.setProperty("javax.net.ssl.trustStore", "trust-store.jks");
  System.setProperty("javax.net.ssl.trustStorePassword", "TrustStore");
  ...
}

另一种方法是将密钥存储库作为资源文件放在项目jar文件中并加载它:

public static SSLContext createSSLContext(String resourcePath, String pass) throws NoSuchAlgorithmException, KeyStoreException, IOException, CertificateException, UnrecoverableKeyException, KeyManagementException {
  // initialise the keystore
  final char[] password = pass.toCharArray();
  KeyStore ks = KeyStore.getInstance("JKS");
  ks.load(ThisClass.class.getResourceAsStream(resourcePath
  ), password);

  // Setup the key manager factory.
  KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
  kmf.init(ks, password);

  // Setup the trust manager factory.
  TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");
  tmf.init(ks);

  SSLContext sslc = SSLContext.getInstance("TLS");
  sslc.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);
  return sslc;
}

public static void main(String[] args) {
  SSLContext.setDefault(
    createSSLContext("/trust-store.jks", "TrustStore"));
  ...
}

在windows中，您也可以尝试这个解决方案:https://stackoverflow.com/a/59056537/980442

我从证书颁发机构CA .crt文件中创建了keystore文件，如下所示:

keytool -import -alias ca -keystore trust-store.jks -storepass TrustStore -trustcacerts -file ca.crt

供参考:https://docs.oracle.com/javadb/10.8.3.0/adminguide/cadminsslclient.html

首先下载ssl证书，然后您可以转到您的java bin路径在控制台中执行以下命令。

C:\java\JDK1.8.0_66-X64\bin>keytool -printcert -file C:\Users\lova\openapi.cer -keystore openapistore

我有同样的问题与证书错误，这是因为SNI:我使用的http客户端没有SNI实现。所以版本更新起了作用

   <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.3.6</version>
    </dependency>

这是我在macOS上使用的方法。将server-name和server-port替换为您自己的。

在终端上运行这两个命令。

从远程服务器下载证书

openssl x509 -in <(openssl s_client -connect server-name:server-port -prexit 2>/dev/null) -out ~/server-name.crt

将证书导入Java密钥存储库

sudo keytool -importcert -file ~/server-name.crt -alias server-name -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit

重新启动应用程序，certs错误就会消失!

我能够让它只与代码工作，即不需要使用keytool:

import com.netflix.config.DynamicBooleanProperty;
import com.netflix.config.DynamicIntProperty;
import com.netflix.config.DynamicPropertyFactory;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.ssl.SSLContexts;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.conn.ssl.X509HostnameVerifier;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClients;
import org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager;
import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor;
import org.apache.http.impl.nio.reactor.IOReactorConfig;
import org.apache.http.nio.conn.NoopIOSessionStrategy;
import org.apache.http.nio.conn.SchemeIOSessionStrategy;
import org.apache.http.nio.conn.ssl.SSLIOSessionStrategy;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import java.io.IOException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

public class Test
{
    private static final DynamicIntProperty MAX_TOTAL_CONNECTIONS = DynamicPropertyFactory.getInstance().getIntProperty("X.total.connections", 40);
    private static final DynamicIntProperty ROUTE_CONNECTIONS = DynamicPropertyFactory.getInstance().getIntProperty("X.total.connections", 40);
    private static final DynamicIntProperty CONNECT_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.connect.timeout", 60000);
    private static final DynamicIntProperty SOCKET_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.socket.timeout", -1);
    private static final DynamicIntProperty CONNECTION_REQUEST_TIMEOUT = DynamicPropertyFactory.getInstance().getIntProperty("X.connectionrequest.timeout", 60000);
    private static final DynamicBooleanProperty STALE_CONNECTION_CHECK = DynamicPropertyFactory.getInstance().getBooleanProperty("X.checkconnection", true);

    public static void main(String[] args) throws Exception
    {

        SSLContext sslcontext = SSLContexts.custom()
                .useTLS()
                .loadTrustMaterial(null, new TrustStrategy()
                {
                    @Override
                    public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException
                    {
                        return true;
                    }
                })
                .build();
        SSLIOSessionStrategy sslSessionStrategy = new SSLIOSessionStrategy(sslcontext, new AllowAll());

        Registry<SchemeIOSessionStrategy> sessionStrategyRegistry = RegistryBuilder.<SchemeIOSessionStrategy>create()
                .register("http", NoopIOSessionStrategy.INSTANCE)
                .register("https", sslSessionStrategy)
                .build();

        DefaultConnectingIOReactor ioReactor = new DefaultConnectingIOReactor(IOReactorConfig.DEFAULT);
        PoolingNHttpClientConnectionManager connectionManager = new PoolingNHttpClientConnectionManager(ioReactor, sessionStrategyRegistry);
        connectionManager.setMaxTotal(MAX_TOTAL_CONNECTIONS.get());
        connectionManager.setDefaultMaxPerRoute(ROUTE_CONNECTIONS.get());

        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(SOCKET_TIMEOUT.get())
                .setConnectTimeout(CONNECT_TIMEOUT.get())
                .setConnectionRequestTimeout(CONNECTION_REQUEST_TIMEOUT.get())
                .setStaleConnectionCheckEnabled(STALE_CONNECTION_CHECK.get())
                .build();

        CloseableHttpAsyncClient httpClient = HttpAsyncClients.custom()
                .setSSLStrategy(sslSessionStrategy)
                .setConnectionManager(connectionManager)
                .setDefaultRequestConfig(requestConfig)
                .build();

        httpClient.start();

        // use httpClient...
    }

    private static class AllowAll implements X509HostnameVerifier
    {
        @Override
        public void verify(String s, SSLSocket sslSocket) throws IOException
        {}

        @Override
        public void verify(String s, X509Certificate x509Certificate) throws SSLException {}

        @Override
        public void verify(String s, String[] strings, String[] strings2) throws SSLException
        {}

        @Override
        public boolean verify(String s, SSLSession sslSession)
        {
            return true;
        }
    }
}