AWS Lambda Java，写入 S3 存储桶

Question

I am creating an AWS Lambda function that is runned monthly. Each month process some data and write that back to S3 Bucket.

Do you know how you can you write a file from AWS Lambda Java to a S3 bucket?

Answer 1

Yes, you have to create a text file in S3 bucket and take a reference of the following code to update the file contents as per your requirement.

AmazonS3 client = new AmazonS3Client();
/**
 * @param bucketName
 *            The name of the bucket to place the new object in.
 * @param key
 *            The key of the object to create.
 * @param content
 *            The String to encode
 */
client.putObject("**Bucket Name**", "**File Name to write**", "updated string contents");

Answer 2

The same way you can write a file to S3 from any Java application. Use the AWS SDK for Java .

Answer 3

I would advise using the AWS Kinesis FireHose service that allows to send data as strings from the AWS SDK . The service will write the files for you, aggregate events, and even compress the files with timestamps.

Answer 4

Try this:

try{
            // Create new file
            Util._logger.log(" Creating file transfer ");

            StringBuilder stringBuilder = new StringBuilder();

            //Writing in file
            stringBuilder.append('Data you want to write in file');

            // Upload file
            ByteArrayInputStream inputStream = new ByteArrayInputStream(stringBuilder.toString().getBytes(Constants.UTF_8));
            s3Client.putObject(dstBucket, uploadFileName, inputStream, new ObjectMetadata());

        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (AmazonServiceException ase) {
            System.out.println("Caught an AmazonServiceException, " +
                    "which means your request made it " + 
                    "to Amazon S3, but was rejected with an error " +
                    "response for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
            Util._logger.log(Constants.EXCEPTION_ERROR + ase.getMessage());
            ase.printStackTrace();
        } catch (AmazonClientException ace) {
                System.out.println("Caught an AmazonClientException, " +
                        "which means the client encountered " +
                        "an internal error while trying to " +
                        " communicate with S3, " +
                        "such as not being able to access the network.");
                System.out.println(Constants.EXCEPTION_ERROR + ace.getMessage());
                Util._logger.log(Constants.EXCEPTION_ERROR + ace.getMessage());
                ace.printStackTrace();
        } catch (Exception e) {
                Util._logger.log(Constants.EXCEPTION_ERROR + e.getMessage());
                e.printStackTrace();
        }

Answer 5

Here is a sample from official Git repo

https://github.com/awsdocs/aws-lambda-developer-guide/blob/master/sample-apps/s3-java/src/main/java/example/Handler.java