您可以使用以下代码示例解决“AWS Java SDK - 发送SAML请求到STS - 无法找到请求目标的有效证书路径。”问题：

import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClientBuilder;
import com.amazonaws.services.securitytoken.model.AssumeRoleWithSAMLRequest;
import com.amazonaws.services.securitytoken.model.AssumeRoleWithSAMLResult;
import com.amazonaws.services.securitytoken.model.Credentials;

public class STSExample {

    public static void main(String[] args) {
        String roleArn = "arn:aws:iam::123456789012:role/RoleName";
        String principalArn = "arn:aws:iam::123456789012:saml-provider/ProviderName";
        String samlAssertion = ""; // Replace with your SAML assertion

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

        AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard()
                .withCredentials(new AWSStaticCredentialsProvider(basicCredentials))
                .build();

        AssumeRoleWithSAMLRequest assumeRoleWithSAMLRequest = new AssumeRoleWithSAMLRequest()
                .withRoleArn(roleArn)
                .withPrincipalArn(principalArn)
                .withSAMLAssertion(samlAssertion);

        AssumeRoleWithSAMLResult assumeRoleWithSAMLResult = stsClient.assumeRoleWithSAML(assumeRoleWithSAMLRequest);
        Credentials credentials = assumeRoleWithSAMLResult.getCredentials();

        System.out.println("Access Key ID: " + credentials.getAccessKeyId());
        System.out.println("Secret Access Key: " + credentials.getSecretAccessKey());
        System.out.println("Session Token: " + credentials.getSessionToken());
        System.out.println("Expiration: " + credentials.getExpiration());
    }
}

在代码中，您需要替换以下部分：

• roleArn：目标角色的 Amazon Resource Name (ARN)
• principalArn：SAML 提供程序的 Amazon Resource Name (ARN)
• samlAssertion：SAML 断言（替换为您的实际 SAML 断言）
• YOUR_AWS_ACCESS_KEY：您的 AWS 访问密钥
• YOUR_AWS_SECRET_ACCESS_KEY：您的 AWS 密钥访问密钥

确保您已经安装了 AWS Java SDK 并导入了所需的依赖项。此代码将使用提供的 SAML 断言向 AWS Security Token Service (STS) 发送请求，并从响应中获取临时凭证。