Java line.split() for csv file returning empty strings

Question

I'm trying to read from this CSV file that looks like

"1.23","2.45","3.25"
"4","5","6"
"7","8","9"
"10","11","12"

Now the problem is that while Java can find my file, line split isn't returning what I'm expecting.

Here is my attempt at reading from the csv file.

          File root = new  File(Thread.currentThread().getContextClassLoader().getResource("").toURI());
          File resource = new File(root, "coords.csv");
          float[] x = new float[5000];
                     float[] y = new float[5000];
                     float[] z = new float[5000];
                     int coordIndex = 0; 
                     BufferedReader br = null; 
                     String line = "";
                     String cvsSplitBy = ",";
                     /* 1, 2, 3,
                      * 3, 5, 6,
                      */
                     try{
                         System.out.println(coordIndex);
                         br = new BufferedReader(new FileReader(resource));
                         String[] coordinates = line.split(cvsSplitBy);
/*I get an error from accessing an array out of bounds */ 
                         System.out.println(coordinates[0]);
                         System.out.println(coordinates[1]);
                         System.out.println(coordinates[2]);
                         x[coordIndex] = Float.parseFloat(coordinates[0]);
                         y[coordIndex] = Float.parseFloat(coordinates[1]);
                         z[coordIndex] = Float.parseFloat(coordinates[2]);
                         coordIndex++;
                     }catch (FileNotFoundException e) {
                        e.printStackTrace();
                     } catch (IOException e) {
                        e.printStackTrace();
                     } finally {
                        if (br != null) {
                            try {
                                br.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                     }

Here is my output error:

IOException:  java.lang.ArrayIndexOutOfBoundsException: 1

Any ideas??

Get rid of quotes (") first with replaceAll() and then split by comma (,). As of know your are leaving both leading and trailing quotes. — PM 77-1
– PM 77-1, Commented Dec 1, 2013 at 23:43

Jeroen Vannevel · Accepted Answer · 2013-12-01 23:41:32Z

1

String line = "";
br = new BufferedReader(new FileReader(resource));
String[] coordinates = line.split(cvsSplitBy);

You never have data in your line.

You have to add a loop to read everything:

while(line = br.readLine() != null) { }

answered Dec 1, 2013 at 23:41

Jeroen Vannevel

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Ingo · Accepted Answer · 2013-12-01 23:42:26Z

0

Your line you are splitting is the empty line. This results in split returning an empty array.

The error you get is typical for non-defensive programming: the result of split() depends entirely on user input (that you do not know ex ante), hence it is a must to check the result:

coords = line.split(",");
if (coords.length == 3) {
      // looks good
}
else {
  System.err.println("Bad data: " + line);
}

answered Dec 1, 2013 at 23:42

Ingo

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Comments

Samuel · Accepted Answer · 2013-12-01 23:43:04Z

0

line is empty. You're never assigning a value other than ""...

answered Dec 1, 2013 at 23:43

Samuel

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