您已经拥有的证书可能是服务器证书，或者用于签署服务器证书的证书。您将需要它，这样您的web服务客户机才能对服务器进行身份验证。

But if additionally you need to perform client authentication with SSL, then you need to get your own certificate, to authenticate your web service client. For this you need to create a certificate request; the process involves creating your own private key, and the corresponding public key, and attaching that public key along with some of your info (email, name, domain name, etc) to a file that's called the certificate request. Then you send that certificate request to the company that's already asked you for it, and they will create your certificate, by signing your public key with their private key, and they'll send you back an X509 file with your certificate, which you can now add to your keystore, and you'll be ready to connect to a web service using SSL requiring client authentication.

要生成证书请求，使用"keytool -certreq -alias -file -keypass -keystore "。将生成的文件发送给将要签署该文件的公司。

当你取回你的证书时，运行"keytool -importcert -alias -keypass -keystore "。

如果密钥存储库受到保护(这是个好主意)，那么在这两种情况下都可能需要使用-storepass。

将从浏览器下载的.cer证书文件(打开url并挖掘详细信息)导入到java_home\jre\lib\security中的cacerts密钥存储库中，而不是尝试生成和使用我自己的密钥存储库。

转到java_home\jre\lib\security (Windows)使用cmd和CTRL+SHIFT+ENTER打开管理命令行 2 .执行keytool命令导入证书。 (替换你的aliasname和路径\到\证书。cer)

 ..\..\bin\keytool -import -trustcacerts -keystore cacerts -storepass changeit -noprompt -alias yourAliasName -file path\to\certificate.cer

这样您就不必指定任何额外的JVM选项，并且证书应该可以被JRE识别。

If you want to authenticate you need the private key - there is no other option. A certificate is a public key with extra properties (like company name, country,...) that is signed by some Certificate authority that guarantees that the attached properties are true. .CER files are certificates and don't have the private key. The private key is provided with a .PFX keystore file normally. If you really authenticate is because you already had imported the private key. You normally can import .CER certificates without any problems with keytool -importcert -file certificate.cer -keystore keystore.jks -alias "Alias"

您已经拥有的证书可能是服务器证书，或者用于签署服务器证书的证书。您将需要它，这样您的web服务客户机才能对服务器进行身份验证。

But if additionally you need to perform client authentication with SSL, then you need to get your own certificate, to authenticate your web service client. For this you need to create a certificate request; the process involves creating your own private key, and the corresponding public key, and attaching that public key along with some of your info (email, name, domain name, etc) to a file that's called the certificate request. Then you send that certificate request to the company that's already asked you for it, and they will create your certificate, by signing your public key with their private key, and they'll send you back an X509 file with your certificate, which you can now add to your keystore, and you'll be ready to connect to a web service using SSL requiring client authentication.

要生成证书请求，使用"keytool -certreq -alias -file -keypass -keystore "。将生成的文件发送给将要签署该文件的公司。

当你取回你的证书时，运行"keytool -importcert -alias -keypass -keystore "。

如果密钥存储库受到保护(这是个好主意)，那么在这两种情况下都可能需要使用-storepass。

下面是我一直用于以编程方式将.cer文件导入到新的KeyStore中的代码。

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
//VERY IMPORTANT.  SOME OF THESE EXIST IN MORE THAN ONE PACKAGE!
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;

//Put everything after here in your function.
KeyStore trustStore  = KeyStore.getInstance(KeyStore.getDefaultType());
trustStore.load(null);//Make an empty store
InputStream fis = /* insert your file path here */;
BufferedInputStream bis = new BufferedInputStream(fis);

CertificateFactory cf = CertificateFactory.getInstance("X.509");

while (bis.available() > 0) {
    Certificate cert = cf.generateCertificate(bis);
    trustStore.setCertificateEntry("fiddler"+bis.available(), cert);
}

虽然已经提供了很多很好的答案，但我想给出一个以编程方式加载ssl材料的替代方案。您可以尝试下面的代码片段:

Path certificatePath = Paths.get("/path/to/certificate.cer");
List<Certificate> certificates = CertificateUtils.loadCertificate(certificatePath);

SSLFactory sslFactory = SSLFactory.builder()
        .withTrustMaterial(certificates)
        .build();

SSLContext sslContext = sslFactory.getSslContext();

它可以处理pem, der(二进制)和p7b格式的文件。这个示例代码片段来自库:GitHub - SSLContext Kickstart你可以添加下面的代码片段:

<dependency>
    <groupId>io.github.hakky54</groupId>
    <artifactId>sslcontext-kickstart</artifactId>
    <version>7.0.2</version>
</dependency>