java - AWS S3 Java : doesObjectExist results in 403: FORBIDDEN

Question

我的 Java 程序使用 AWS SDK 与 S3 存储桶交互时遇到问题。

这是我用来创建 S3 客户端的代码:

public S3StorageManager(S3Config config) throws StorageException {

   BasicAWSCredentials credentials = new BasicAWSCredentials(myAccessKey(), mySecretKey());
   AWSStaticCredentialsProvider provider = new AWSStaticCredentialsProvider(credentials);

   this.s3Client = AmazonS3ClientBuilder
        .standard()
        .withCredentials(provider)
        .withRegion(myRegion)
        .build();

当我尝试下载文件时，在开始下载之前我检查文件是否存在:

s3Client.doesObjectExists(bucketName, objectName);

这是我得到 403:FORBIDDEN 的地方。奇怪的是，只有当我在同一 session 中执行上传之前尝试执行对象存在性检查时，才会出现此问题。换句话说，在初始化 s3Client 之后: - 如果我首先尝试检查一个对象是否存在，它会引发 FORBIDDEN 问题； - 如果我首先执行文件上传，它工作正常，之后任何对象存在检查也工作正常；

这是我的堆栈跟踪:

com.amazonaws.services.s3.model.AmazonS3Exception: Forbidden (Service: Amazon S3; Status Code: 403; Error Code: 403 Forbidden; Reques
t ID: A23BB805491E411F)
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleErrorResponse(AmazonHttpClient.java:1588) ~[aws-java-sdk-core-1.
11.128.jar:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1258) ~[aws-java-sdk-core-1.11
.128.jar:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1030) ~[aws-java-sdk-core-1.11.128
.jar:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:742) ~[aws-java-sdk-core-1.11.128.jar:
?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:716) ~[aws-java-sdk-core-1.11.1
28.jar:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:699) ~[aws-java-sdk-core-1.11.128.jar:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:667) ~[aws-java-sdk-core-1.11.128.jar
:?]
        at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:649) ~[aws-java-sdk-core-1.1
1.128.jar:?]
        at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:513) ~[aws-java-sdk-core-1.11.128.jar:?]
        at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4169) ~[aws-java-sdk-s3-1.11.128.jar:?]
        at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4116) ~[aws-java-sdk-s3-1.11.128.jar:?]
        at com.amazonaws.services.s3.AmazonS3Client.getObjectMetadata(AmazonS3Client.java:1237) ~[aws-java-sdk-s3-1.11.128.jar:?]
        at com.amazonaws.services.s3.AmazonS3Client.getObjectMetadata(AmazonS3Client.java:1213) ~[aws-java-sdk-s3-1.11.128.jar:?]
        at com.amazonaws.services.s3.AmazonS3Client.doesObjectExist(AmazonS3Client.java:1272) ~[aws-java-sdk-s3-1.11.128.jar:?]

另一件奇怪的事情是，当我将我的 Java 程序移动到 EC2 远程机器时，所有这些问题都开始了。如果我在我的本地机器上执行它，S3 交互工作正常。但是我不认为问题取决于 IAM 角色，因为我使用 AWSStaticCredentialsProvider。

Answer 1

您的凭据可能是正确的，但如果您没有设置正确的 IAM 策略，您仍然会被禁止访问。要检查 s3 中的对象，您需要以下内容:

{
    "Version":"2012-10-17",
    "Statement":[
        {
            "Effect":"Allow",
            "Action":[
            "s3:ListBucket"
            ],
            "Resource":["arn:aws:s3:::examplebucket"]
        },
        {
            "Effect":"Allow",
            "Action":[
            "s3:GetObject"
            ],
          "Resource":["arn:aws:s3:::examplebucket/*"]
        }
    ]
}