要使用AWS SDK for Java版本2删除S3文件夹或删除多个S3对象，可以使用以下代码示例：

1. 删除S3文件夹：

import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
import software.amazon.awssdk.services.s3.model.S3Object;

import java.util.List;

public class S3FolderDeletionExample {

    public static void main(String[] args) {
        String bucketName = "your_bucket_name";
        String folderName = "your_folder_name";

        S3Client s3Client = S3Client.create();

        // 列出文件夹中的所有对象
        ListObjectsV2Request listObjectsRequest = ListObjectsV2Request.builder()
                .bucket(bucketName)
                .prefix(folderName + "/") // 使用前缀来过滤文件夹中的对象
                .build();
        
        ListObjectsV2Response listObjectsResponse = s3Client.listObjectsV2(listObjectsRequest);
        List objects = listObjectsResponse.contents();

        // 删除每个对象
        for (S3Object s3Object : objects) {
            String key = s3Object.key();
            DeleteObjectRequest deleteObjectRequest = DeleteObjectRequest.builder()
                    .bucket(bucketName)
                    .key(key)
                    .build();
            s3Client.deleteObject(deleteObjectRequest);
        }

        System.out.println("S3文件夹删除成功！");
    }
}

2. 删除多个S3对象：

import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.DeleteObjectsRequest;
import software.amazon.awssdk.services.s3.model.DeleteObjectsResponse;
import software.amazon.awssdk.services.s3.model.DeleteObjectsResponseDeletedObject;

import java.util.ArrayList;
import java.util.List;

public class S3ObjectDeletionExample {

    public static void main(String[] args) {
        String bucketName = "your_bucket_name";

        S3Client s3Client = S3Client.create();

        // 创建要删除的对象列表
        List objectsToDelete = new ArrayList<>();
        objectsToDelete.add(DeleteObjectsRequest.builder().key("object_key1").build());
        objectsToDelete.add(DeleteObjectsRequest.builder().key("object_key2").build());
        // 添加更多要删除的对象

        // 删除多个对象
        DeleteObjectsRequest deleteObjectsRequest = DeleteObjectsRequest.builder()
                .bucket(bucketName)
                .delete(Delete.builder().objects(objectsToDelete).build())
                .build();
        DeleteObjectsResponse deleteObjectsResponse = s3Client.deleteObjects(deleteObjectsRequest);
        List deletedObjects = deleteObjectsResponse.deleted();

        // 打印已删除的对象
        System.out.println("已删除的对象：");
        for (DeleteObjectsResponseDeletedObject deletedObject : deletedObjects) {
            System.out.println("已删除对象的键：" + deletedObject.key());
        }
    }
}

请确保替换示例代码中的your_bucket_name和your_folder_name为实际的S3存储桶名称和文件夹名称。另外，您还需要在代码中提供AWS凭证，例如通过配置~/.aws/credentials文件或使用环境变量。