Write csv file to S3 Bucket without storing it locally - amazon-web-services

Question

Before I used to create a .csv file and store it in a local system where the application is running and then I used to send it to AWS S3 Bucket.
Now I don't want to create any file on the application side. I want to write my data to S3 Bucket as a .csv file directly, Is it possible? If possible please guide me the way I can do this.

Answer 1

There is a way to achieve this, we have to send our data as InputStream
In my case, I did these changes:
[1]I updated my Bean class to Override toString() method as follows
public class Employee{
String Id;
String employeeNo;
String name;
//get and set
#Override
public String toString() {
return "{"+ Id +","+ employeeNo + ","+ name + "}";
}
[2]I took the list of data and converted into List<String[]>
List<Employee> employeeList=//get employee list
List<String[]> csvData = toStringArray(employeeList);
My toStringArray() will return List<String[]>
private List<String[]> toStringArray(List<Employee> employeeList) {
List<String[]> records = new ArrayList<String[]>();
// adding header to csv
records.add(new String[] { "EmployeeId", "EmployeeNo", "Name"});
// add data to csv
Iterator<Employee> emp = employeeList.iterator();
while (emp.hasNext()) {
Employee data = emp.next();
records.add(new String[] { emp.getId(), emp.getEmployeeNo(), emp.getName() });
}
return records;
}
[3] Now I converted this data to String
String strCsvData=writeCsvAsString(csvData);
my writeCsvAsString() method is
public String writeCsvAsString(List<String[]> csvData) {
StringWriter s = new StringWriter();
CSVWriter writer = new CSVWriter(s);
writer.writeAll(csvData);
try {
writer.close();
} catch (IOException e) {
}
String finalString = s.toString();
logger.debug("Actual data:- {}", finalString);
return finalString;
}
Now I converted this String into InputStream and I send this to S3 bucket with contentType metadata "text/csv"
InputStream targetStream = new ByteArrayInputStream(strCsvData.getBytes());