CODEWITHSUNDEEP
javabufferedwriter
Eduardo
Eduardo

Reputation: 7141

Java BufferedWriter isn't working

Im having a problem with a BufferedWriter. I am reading in a 50,000 word wordlist, using a stemming algorithm and creating a new wordlist that just contains the word stems. Instead of this new file containing any stems however it litrally just contains:

-

Here is my code:

public static void main(String[] args) {
    BufferedReader reader=null;
    BufferedWriter writer=null;
    try {
        writer = new BufferedWriter(new FileWriter(new File("src/newwordlist.txt")));
        HashSet<String> db = new HashSet<String>();
        reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/wordlist"),"UTF-8"));
        String word;
        int i=0;
        while ((word=reader.readLine())!=null) {
            i++;
            Stemmer s= new Stemmer();
            s.addword(word);
            s.stem();
            String stem =s.toString();
            if(!db.contains(stem)){
                db.add(stem);
                writer.write(stem);
                //System.out.println(stem);
            }
        }
        System.out.println("Reduced file from " + i + " words to " + db.size());
        reader.close();
        writer.close();
    } catch (IOException e1) {
        e1.printStackTrace();
    }
}

The output i get on the console is:

Reduced file from 58110 words to 28201

So i know its working. Ive also tried changing writer.write(stem); to writer.write("hi"); and I still get the same output in newwordlist.txt. I know its no fault of the Stemmer class, Ive tried outputting the stem string (where I commented the code) and that produced the correct output to console so the fault must be with the writer but I dont understand what.

Edit 1

I simplified to code to:

        BufferedReader reader=null;
        BufferedWriter writer=null;
        try {
            writer = new BufferedWriter(new FileWriter(new File("src/newwordlist.txt")));
            HashSet<String> db = new HashSet<String>();
            reader = new BufferedReader(new InputStreamReader(new FileInputStream("src/wordlist.txt"),"UTF-8"));
            String word;
            int i=0;
            while ((word=reader.readLine())!=null) {
                i++;
                if(!db.contains(word)){
                    db.add(word);
                    writer.write("hi");
                }
            }
            System.out.println("Reduced file from " + i + " words to " + db.size());
            reader.close();
            writer.close();
        } catch (IOException e1) {
            e1.printStackTrace();
        }

Now i get console output:

Reduced file from 58110 words to 58109

But the output file is still blank

Upvotes: 1

Views: 572

Answers (5)

Stephen C
Stephen C

Reputation: 718798

I would expect the code as given in the Question to produce a file that consists of one line, consisting of all of the "stems" concatenated. (Or in the "hi" version, one line consisting of "hihihi...." repeated a large number of times.)

It is conceivable that whatever you are using to view the file cannot cope with an input file that consists of many thousands of characters ... and no end-of-line.

Change

    writer.write(stem);

to 

    writer.write(stem);
    writer.write(EOL);

where EOL is the platform specific end-of-line sequence.

Assuming you are using Java 7, it would be better to use try-with-resource to make sure that the output stream is always closed / flushed, even if there is an error:

public static void main(String[] args) {
    try (BufferedReader reader = new BufferedReader(
             new InputStreamReader(new FileInputStream("src/wordlist"), "UTF-8"));
         BufferedWriter writer = new BufferedWriter(new FileWriter(
             new File("src/newwordlist.txt")));
        HashSet<String> db = new HashSet<>();
        String EOL = System.getProperty("line.separator");
        String word;
        int i = 0;
        while ((word = reader.readLine()) != null) {
            i++;
            Stemmer s = new Stemmer();
            s.addword(word);
            s.stem();
            String stem = s.toString();
            if (db.add(stem)) {
                writer.write(stem);
                writer.write(EOL);
            }
        }
        System.out.println("Reduced file from " + i + " words to " + db.size());
    } catch (IOException e1) {
        e1.printStackTrace();
    }
}

(I tidied up a couple of other things too ...)

Upvotes: 1

Jesko R.
Jesko R.

Reputation: 827

According to the Java documentation you need to use BufferedWriter.write() as follows:

write(string,offset,length);

so try:

writer.write(stem,0,stem.length());

Upvotes: 1

Qwerky
Qwerky

Reputation: 18445

Works for me. Is this your exact class, did you edit it before pasting in?

wordlist;

the
cat
sat
on
the
mat

newwordlist.txt;

thecatsatonmat

My Stemmer just returns the word you gave it.

public class Stemmer {

    private String word;

    public void addword(String word) {
        this.word = word;
    }

    public void stem() {
        // TODO Auto-generated method stub

    }

    @Override
    public String toString() {
        return word;
    }

}

Upvotes: 1

Peter Lawrey
Peter Lawrey

Reputation: 533510

When I run your edited code I get one line with

hihihihihihihihihihihihihi ............

As expected.

Perhaps you intended to add newline characters line this.

           if(!db.contains(word)){
                db.add(word);
                writer.write(word);
                writer.write("\n");
            }

Upvotes: 0

Yuriy Nakonechnyy
Yuriy Nakonechnyy

Reputation: 3842

The reason you get Reduced file from 58110 words to 58109 console output is that you only have one System.out.println statement after the loop.

The writer should write words only to the output file src/newwordlist.txt and not to the console. If you want your program to output words to the console add additional System.out.println(word) after writer.write("hi");

Hope this helps...

Upvotes: 1

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