AWS Java SDK-向STS发送SAML请求-找不到请求目标的有效认证路径

我正在尝试向AWS STS发送SAML请求，以获取可用于与其他AWS服务进行身份验证的临时凭据。下面是我的代码：

BasicAWSCredentials basicCreds=new BasicAWSCredentials("", "");

AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard().withCredentials(new AWSStaticCredentialsProvider(basicCreds)).withRegion(Regions.DEFAULT_REGION.getName()).build();
AssumeRoleWithSAMLRequest samlReq = new AssumeRoleWithSAMLRequest();
samlReq.setRoleArn(role_arn);
samlReq.setPrincipalArn(principal_arn);
samlReq.setSAMLAssertion(assertion);
AssumeRoleWithSAMLResult token = stsClient.assumeRoleWithSAML(samlReq);

请求需要通过代理，我已经在代码中设置了代理。当我运行它时，我看到以下错误：

INFO: Configuring Proxy. Proxy Host: xxx.xxx.com Proxy Port: 9400
com.amazonaws.SdkClientException: Unable to execute HTTP request: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleRetryableException(AmazonHttpClient.java:1201)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1147)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:796)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:764)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:738)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:698)
    at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:680)
    at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:544)
    at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:524)
    at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.doInvoke(AWSSecurityTokenServiceClient.java:1719)
    at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.invoke(AWSSecurityTokenServiceClient.java:1686)
    at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.invoke(AWSSecurityTokenServiceClient.java:1675)
    at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.executeAssumeRoleWithSAML(AWSSecurityTokenServiceClient.java:817)
    at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.assumeRoleWithSAML(AWSSecurityTokenServiceClient.java:788)
    at Hello.main(Hello.java:338)

这发生在

AssumeRoleWithSAMLResult-token=stsClient.assumeRoleWithSAML（samlReq）行。我知道当cacerts文件中缺少服务器证书时会发生此错误。我正在本地笔记本电脑上运行代码，所以使用的是我自己的cacerts文件

现在，我想知道是否必须添加代理服务器证书或AWS证书？如果我应该添加AWS证书，我可以从哪里获得？这个问题还有其他解决方法吗

任何帮助都将不胜感激，谢谢