s3 aws 临时授权

package com.s3demo.util;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.auth.BasicSessionCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClientBuilder;
import com.amazonaws.services.securitytoken.model.AssumeRoleRequest;
import com.amazonaws.services.securitytoken.model.AssumeRoleResult;
import com.amazonaws.services.securitytoken.model.Credentials;

import java.util.List;

public class MakingRequestsWithIAMTempCredentials {
    public static void main(String[] args) {
        String clientRegion = "us-east-1";
        String roleARN = "";
        String roleSessionName = "";
        String bucketName = "";
        String awsAccessKey = "";
        String awsSecretKey = "";


        try {
            // Creating the STS client is part of your trusted code. It has
            // the security credentials you use to obtain temporary security credentials.
            BasicAWSCredentials awsCreds = new BasicAWSCredentials(awsAccessKey, awsSecretKey);
            AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard()
                                                    .withCredentials(new AWSStaticCredentialsProvider(awsCreds))
                                                    .withRegion(clientRegion)
                                                    .build();

            // Obtain credentials for the IAM role. Note that you cannot assume the role of an AWS root account;
            // Amazon S3 will deny access. You must use credentials for an IAM user or an IAM role.
            AssumeRoleRequest roleRequest = new AssumeRoleRequest()
                                                    .withRoleArn(roleARN)
                                                    .withRoleSessionName(roleSessionName);
            AssumeRoleResult roleResponse = stsClient.assumeRole(roleRequest);
            Credentials sessionCredentials = roleResponse.getCredentials();

            // Create a BasicSessionCredentials object that contains the credentials you just retrieved.
            BasicSessionCredentials awsCredentials = new BasicSessionCredentials(
                    sessionCredentials.getAccessKeyId(),
                    sessionCredentials.getSecretAccessKey(),
                    sessionCredentials.getSessionToken());

            // Provide temporary security credentials so that the Amazon S3 client
	    // can send authenticated requests to Amazon S3. You create the client
	    // using the sessionCredentials object.
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                                    .withCredentials(new AWSStaticCredentialsProvider(awsCredentials))
                                    .withRegion(clientRegion)
                                    .build();

            // Verify that assuming the role worked and the permissions are set correctly
            // by getting a set of object keys from the bucket.
            List<Bucket> buckets = s3Client.listBuckets();
            System.out.println("No. of Objects: " + buckets.size());
        }
        catch(AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        }
        catch(SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}