Question

I am having an issue while parsing a CSV file. It is only 2 rows of data with a comma separating them. Row one is a date and row 2 is a value. The date field will always have dates in it but sometimes the value is blank (or null?). When it gets to the null value I get a StringIndexOutOfBoundsException and the app crashes. I am logging each loop and can see the data but as soon as I get to a null value it stops looping and gives the error. If there are no null values then it works perfect. Here is my code:

        BufferedReader buf = new BufferedReader(new StringReader(file));
        String line = null;
        while ((line = buf.readLine()) != null) {
            try {
                String date = null, value = null;
                String[] RowData = line.split(",");
                date = RowData[0];
                value = RowData[1]; (this is the row it crashes on)

This is what the CSV looks like:

2011-08-28 09:16,8.23

2011-08-28 09:15,8.24

2011-08-28 09:14,8.26

2011-08-28 09:13,8.34

2011-08-28 09:12,

2011-08-28 09:11,10.72

2011-08-28 09:10,

2011-08-28 09:09,

the value at 09:13 is the last thing in logcat before I get the error.

This fixed it:

                if(RowData.length == 2) {
                    date = RowData[0];
                    value = RowData[1];
                } else {
                    date = RowData[0];
                    value = "0";
                }

I wrote a 0 in the value field so later processes will not choke on the null value. Thanks for all your help guys!

Answer 1

You want to do this or something like it:

String date = null, value = null;
String[] RowData = line.split(",");
date = RowData[0];

if(RowData.length ==2)value = RowData[1]; (this is the row it crashes on)

Or some variation of it e.g. if(RowData.length < 2) dont attempt to read the value. Its a pretty standard thing – if you ask an array for an index of a value it doesn’t have Java will crash.