Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17


Java parsing, better way to use tokenizer?

Posted on 2007-11-23
Medium Priority
Last Modified: 2008-09-20
I'm trying to parse a csv file (probably made in excel, or access).

Each field is separated by a "," (comma) but some fields are empty, so I'm not getting the data correctly.

Below is what I'm doing now. Is there a better way to parse?

This line works fine:
23, something, aTitle, something, Smith

This line gives me wrong values:


Both come from the same table with 4 fields.

String line = in.readLine();
	StringTokenizer st = new StringTokenizer(line,",");
	int fieldCount=0;
		String nextFieldData = st.nextToken();
			case 1: 
			String ID = (nextFieldData);
			case 3: 
			String Title  = (nextFieldData);
			case 5: 
			String Name  = (nextFieldData);

Open in new window

Question by:polkadot
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 26

Expert Comment

ID: 20339104
there are lot of issues which you have to take care if you do it that ways...

instead try some readily available parsers,

Author Comment

ID: 20339344
csvreader works great, but its a bit bulky, I just wanted some ideas in just parsing it simply ... any other ideas
LVL 27

Expert Comment

ID: 20339554
Then you can't use StringTokenizer, you have to write your own parser.  Read the line character by character, check to see if there's a comma, and parse accordingly.
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

LVL 86

Expert Comment

ID: 20339614

I would not use home-brewed parsing. If it were that simple, there would not be any need for classes such as these
LVL 26

Expert Comment

ID: 20339620
>>StringTokenizer st = new StringTokenizer(line,",");


StringTokenizer st = new StringTokenizer( line,",", true );

and discard the odd( which is the comma ) tokens in the traversing process...
LVL 92

Expert Comment

ID: 20340802
you can find a lightweight csv parser here:
LVL 16

Accepted Solution

gnoon earned 2000 total points
ID: 20344564
I've surveyed the source code of ST. If delemeters are successive (having blank field(s)), they will be group as a delemeter. For example

data: 1,,3,   will become   1,3,   (ST acts with ,, as ,)
return: {1,3,}

ST is not appropriate to parse CSV file.
If you will use JRE 1.4+, use String.split() instead    String[] fields = line.split(",").
If you will use JRE 1.3-, write your own function to parse the line (never use StringTokenizer) and returns array of fields.
LVL 16

Expert Comment

ID: 20344587
public String[] parse(String s, char delim)
    StringBuffer b = new StringBuffer();
    ArrayList a = new ArrayList();
    char c;
    for(int i=0; i<s.length(); i++)
        c = s.charAt(i);
        if(c == delim)
            b = new StringBuffer();
        else b.append(c);
    String[] r = new String[a.size()];
    for(int i=0; i<r.length; i++)
        r[i] = (String) a.get(i);
    return r;

Featured Post

Build and deliver software with DevOps

A digital transformation requires faster time to market, shorter software development lifecycles, and the ability to adapt rapidly to changing customer demands. DevOps provides the solution.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
In this post we will learn how to connect and configure Android Device (Smartphone etc.) with Android Studio. After that we will run a simple Hello World Program.
Viewers learn about the scanner class in this video and are introduced to receiving user input for their programs. Additionally, objects, conditional statements, and loops are used to help reinforce the concepts. Introduce Scanner class: Importing…
This video teaches viewers about errors in exception handling.
Suggested Courses

660 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question