CODEWITHSUNDEEP
javaparsingcsv
Harrison
Harrison

Reputation: 430

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

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??

Upvotes: 0

Views: 2199

Answers (3)

Samuel
Samuel

Reputation: 2156

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

Upvotes: 0

Ingo
Ingo

Reputation: 36349

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);
}

Upvotes: 0

Jeroen Vannevel
Jeroen Vannevel

Reputation: 44448

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) { }

Upvotes: 1

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