CODEWITHSUNDEEP
javaarraysobjectcsvtoken
user2769651
user2769651

Reputation: 171

How to put tokens read from a csv file into an array of objects

I am writing a program that reads from a csv file and puts the values into an array of objects. So I set up an object class that has 5 attributes . What I can't seem to get is how to put the tokenized variables into my array of objects. I did a system.out.printf that uses the getters from my object class to print out the object instances in each index but I get a null pointer. So my guess is that the tokens aren't being stored in my array of objects so how can this be done? This is what I have so far.

EDIT: This is one of the lines on my CSV file 12345,Left-Handed Bacon Stretcher,125.95,PGH,2

EDIT: This is the stacktrace error Im getting for those asking java.lang.NumberFormatException: For input string: " 5" at java.lang.NumberFormatException.forInputString(Unknown Source) at java.lang.Integer.parseInt(Unknown Source) at java.lang.Integer.parseInt(Unknown Source) at Prog6.main(Prog6.java:97)

Part[] part = new Part[20];

String partNumber;
String description;
double price = 0.0;
String warehouseID;
int quantity = 0;

try
{
inFile = new Scanner( new File( "parts.txt" ) );
}
catch( FileNotFoundException e )
{
System.out.println( "Error: File parts.txt not found" );
}

// read file
try
{

while ( inFile.hasNext() )
{
String record = inFile.nextLine();
String[] tokens = record.split(",[ ]*");

partNumber = tokens[0];
description =  tokens[1] ;
price = Double.parseDouble( tokens[2] );
warehouseID =  tokens[3] ;
quantity = Integer.parseInt( tokens[4] );

part[num] = new Part( partNumber, description, price, warehouseID, quantity );
num++;

}
}
catch( Exception e )
{
System.out.println( "File error " + e.getMessage() );
}

// close file
inFile.close();

Upvotes: 0

Views: 2150

Answers (3)

Baby
Baby

Reputation: 5092

Try this and see what happen

try
{   
    int row=1;
    while ( inFile.hasNext() )
    {
        String record = inFile.nextLine();
        String[] tokens = record.split(",");
        if(tokens.length==5){
            partNumber = tokens[0];
            description =  tokens[1] ;
            price = Double.parseDouble( tokens[2].trim());
            warehouseID =  tokens[3] ;
            quantity = Integer.parseInt( tokens[4].trim());
            part[num] = new Part( partNumber, description, price, warehouseID, quantity );
            num++;
        }
        else{
            System.out.println("Row "+row+" skipped (record not complete)");
        }
        row++;
    }
}

Also, you need to check whether tokens[2] and tokens[4] is parseable. in case its value is empty string(""), space or not a number.

Upvotes: 1

coder
coder

Reputation: 4466

  1. First check if your program is going inside while loop, you can either debug or add a print statement

  2. If its going inside while then check the lenght of tokens

  3. Also is it posisble that your file has less than 20 records ?

Also share your exception statck trace and code you using to print each object

Edit:

Instean of System.out.println( "File error " + e.getMessage() ); in catch block write e.printStackTrace()

use this instead:

Integer.parseInt( tokens[4].trim() );

Upvotes: 0

Taylor Hx
Taylor Hx

Reputation: 2833

The problem is that one of the lines in your .csv file look like so:

blah,blah,blah,blah, 5

Notice the space there, that is what is causing the NumberFormatException. Remove this space from your .csv , try (as Rafa El suggests) trimming the String before parsing to an Integer, or try splitting on the following regex: " *, *".

Upvotes: 0

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