CODEWITHSUNDEEP
javafile-ioduplicatesdistinct
Phantom
Phantom

Reputation: 443

Check if a string/line that is going to write into a text file is already exist in the text file

I am analyzing a web access log and try to find out all the unique object (any file or any path) that were requested only once in the access log. Every time the program write into the text file, the content of the text file looks like this :

/~scottp/publish.html
/~ladd/ostriches.html
/~scottp/publish.html
/~lowey/
/~lowey/kevin.gif
/~friesend/tolkien/rootpage.html
/~scottp/free.html
/~friesend/tolkien/rootpage.html
.
.
.

I want to check if the line which is going to write into the text file is already exist in the text file. In order words, if it's does exist in the text file, then do nothing and skip it and analyze the next line. If not, then write it into the text file.

I tried to use equals or contains but it doesn't seems to be work, here's a little pieces of my code:

        // Find Unique Object that were requested only once
        if (matcher3.find()) {
            if(!requestFileName.equals(bw.equals(requestFileName))) {
                bw.write(requestFileName);
                bw.newLine();
            }
        }

What should I do to actually perform a check ?

Upvotes: 0

Views: 1094

Answers (2)

DevilsHnd - 退した
DevilsHnd - 退した

Reputation: 9192

Perhaps something simple like this:

try (BufferedReader br = new BufferedReader(new FileReader(yourFilePath))) {
    boolean lineExists = false; 
    String currentLine;
    while ((currentLine = br.readLine()) != null) {
        if (currentLine.trim().equalsIgnoreCase(requestFileName.trim())) { 
            lineExists = true;
            break;
        }
    }
    br.close();

    if (!lineExists) {
        bw.write(requestFileName);
        bw.newLine();
    }
}
catch (IOException e) { 
    // Do what you want with Exception...
}

Upvotes: 1

guleryuz
guleryuz

Reputation: 2734

As @JB Nizet commented you should make use of Set

Set<String> set = new HashSet<String>();

BufferedReader reader = new BufferedReader(new FileReader(new File("/path/to/yourFile.txt")));

String line;

while((line = reader.readLine()) != null) {

    // duplicate
    if(set.contains(line))
        continue;

    set.add(line);

    // do your work here

}

Upvotes: 2

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