Struts FormFile (parsing .csv files)

[Daniel McDade]

I am allowing our users to upload .csv files, but was having a little trouble deciding how to parse the file content. Normally, I'd wrap the .csv file in a BufferedReader and read it line by line, but with a FormFile object, I only have an InputStream to read the file data. I'm going to add each line in the file to a List object to save to a database.

I'm not a big I/O API expert, so does someone have a clean way to read the .csv data using the Struts FormFile object?

Thanks for any help,
D

[Joe Ess]

InputStream -> InputStreamReader -> BufferedReader

[Daniel McDade]

Joe Ess wrote:InputStream -> InputStreamReader -> BufferedReader

Joe, so something like the following should work? Thanks for your help.

public static List parseUserUpload(FormFile users) {
        List finalUserSet = new ArrayList();
        
        String email = null;
        
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(users.getInputStream()));
            while(br.ready()) {
                email = br.readLine();
                if(email != null && !email.equals(""))
                    finalUserSet.add(email.trim());
            }
            br.close();
        } catch(IOException ioe) {
            
        }
        return finalUserSet;
}

I've been told users can also upload the data as a .txt file, but I'm thinking this should work under that scenario, too.

[David Newton]

A CSV file *is* a text file.

[Daniel McDade]

David Newton wrote:A CSV file *is* a text file.

True enough. :=)

[Joe Ess]

Daniel McDade wrote:

            while(br.ready()) {

Do not do this. ready() does not tell you if the stream has ended, it tells you if a read call will block:

Returns:
True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

javadoc

[Daniel McDade]

Joe Ess wrote:Do not do this. ready() does not tell you if the stream has ended, it tells you if a read call will block:

Joe, based on what I saw, the following would be a better approach, correct?

public static List parseUserUpload(FormFile users) {
        List finalUserSet = new ArrayList();
        
        String email = null;
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(users.getInputStream()));
            while((email = br.readLine()) != null) {
                if(!email.equals(""))
                    finalUserSet.add(email.trim());
            }
        
            br.close();
        } catch(IOException ioe) {
            
        }
        return finalUserSet;
}

[Joe Ess]

Daniel McDade wrote:
Joe, based on what I saw, the following would be a better approach, correct?

Yes, that's how I'd do it