lineByLine 指向整个你文件的内容。这就是你得到 [4,4,4,4,4,4] 的原因。您需要将每一行存储在另一个变量行中，然后使用 tagFinder.find（line）。
最终代码将如下所示

lineByLine points to the entire contents of your file. That is the reason you are getting [4,4,4,4,4,4]. You need to store each line in another variable line and then use tagFinder.find(line). Final code will look like this

while ((lineContents = tempFileReader.readLine()) != null)
{
    String lineByLine = lineContents.replaceAll("/\\.", System.getProperty("line.separator")); //for matching /. and replacing it by new line
    changer.write(lineByLine);
    Pattern pattern = Pattern.compile(".*\\r?\\n"); //Find new line
    Matcher matcher = pattern.matcher(lineByLine);
    while(matcher.find())
    {
        Pattern tagFinder = Pattern.compile("word"); //Finding the word required
        //matcher.group() returns the input subsequence matched by the previous match.
        Matcher tagMatcher = tagFinder.matcher(matcher.group());
        while(tagMatcher.find())
        {
            score++;
        }
        scoreTracker.add(score);
            score = 0;
    }   
}