java.io.FileNotFoundException while accessing from S3 bucket?

Question

I am doing a small POC in AWS. I trying to read a csv file from S3 bucket and displaying in the CloudWatch log files . Everything is going fine but while accessing the file getting java.io.FileNotFoundException

Coding

public class LambdaFunctionHandler implements RequestHandler<S3Event, Report> {

Region AWS_REGION = Region.getRegion(Regions.US_EAST_1);

public Report handleRequest(S3Event s3event, Context context) {
    long startTime = System.currentTimeMillis();
    Report statusReport = new Report();
    LambdaLogger logger = context.getLogger();

    logger.log("Lambda Function Started");
    logger.log("I am inside lambda function");
    Helper helper = new Helper();

    try {
        logger.log("I am inside lambda function2");
        S3EventNotificationRecord record = s3event.getRecords().get(0);
        logger.log("I am inside lambda function3");
        String srcBucket = record.getS3().getBucket().getName();
        logger.log("I am inside lambda function4");
        // Object key may have spaces or unicode non-ASCII characters.
        String srcKey = record.getS3().getObject().getKey().replace('+', ' ');
        logger.log("I am inside lambda function5");
        srcKey = URLDecoder.decode(srcKey, "UTF-8");
        logger.log("I am inside lambda function6");

        AmazonS3 s3Client = new AmazonS3Client();
        logger.log("I am inside lambda function7");
        S3Object s3Object = s3Client.getObject(new GetObjectRequest(srcBucket, srcKey));
        logger.log("I am inside lambda function8");
        statusReport.setFileSize(s3Object.getObjectMetadata().getContentLength());
        logger.log("I am inside lambda function9");

        logger.log("S3 Event Received: " + srcBucket + "/" + srcKey);
        logger.log("I am inside lambda function10");

        File file = new File(srcBucket+"/"+srcKey);
        try {
            Scanner readData =new Scanner(file);
            while(readData.hasNext()) {
                String data = readData.next();
                logger.log("I am inside lambda function data ;;got it");
                //System.out.println("data"+data);
            }
            readData.close();
        }catch(FileNotFoundException e){
            e.printStackTrace();
        }

CloudWatch Log file output

CloudWatch Log Errors

I am inside lambda function

I am inside lambda function2

I am inside lambda function3

I am inside lambda function4

I am inside lambda function5

I am inside lambda function6

I am inside lambda function7

I am inside lambda function8

I am inside lambda function9

S3 Event Received: readfilefromcsvfile/def_nhtsa_crash_test.csv

I am inside lambda function10

java.io.FileNotFoundException:

readfilefromcsvfile/def_nhtsa_crash_test.csv (No such file or directory) java.io.FileNotFoundException: readfilefromcsvfile/def_nhtsa_crash_test.csv (No such file or directory) at java.io.FileInputStream.open0(Native Method)

If we will look into the log output it is telling that no such file, but I have kept it in S3 bucket. Can anyone tell me how to access S3 file in java ? or What is the path name I should give while accessing the S3 bucket file ?

Answer 1

There is no need to create a File instance here. You can simply work on the S3 InputStream.

S3Object s3Object = s3Client.getObject(new GetObjectRequest(srcBucket, srcKey));
....
Scanner scanner = new Scanner(s3Object.getObjectContent());
while (scanner.hasNext()) {
    System.out.println(scanner.next());
}