将 .txt 文件存储在 Arraylist 中

Question

这是我读取文件的完整代码：

public static void main(String[] args) {
    List <String> words = new ArrayList <String>();
    BufferedReader br = null;
    try {
        br = new BufferedReader(new FileReader("3LetterWords.txt"));
        String word;
        while ((word = br.readLine()) != null ){
            words.add(word);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            br.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    String [] wordList = new String[words.size()];
    words.toArray(wordList);
    List<String> combinations = display(new ArrayList<>());
}

public static  List<String> display(ArrayList<String> combinations) {
    int counter = 1;
    for (char c1 = 'a'; c1 <= 'z'; c1++) {
        for (char c2 = 'a'; c2 <= 'z'; c2++) {
            for (char c3 = 'a'; c3 <= 'z'; c3++) {
                String combo = "" + c1 + c2 + c3;                    
                combinations.add(combo);
                System.out.println("" + counter++ + " " + c1 + c2 + c3);
            }
        } 
    }
    return combinations;
}

当我运行程序时，我在输出中得到一个错误，我不确定如何读取或解释（在 NetBeans 中）。 我希望读取.txt文件，然后将其存储到ArrayList中：创建ArrayList以保存文件中的所有信息。 使用ArrayList ，这样您就不必知道文件的大小。

BufferedReader命令定位文件并打开它以供阅读。

while循环逐行读取信息，直到它看到“null”或“end of file”字符。 然后它将每个条目添加到ArrayList 。

catch部分确保您不会读到文件末尾。

第二个try部分关闭文件。

最后一个功能是将ArrayList转换为数组，以便您可以通过它进行搜索。

添加了完整代码：对于上下文：我需要使用 3 个字母单词的 .txt 文件来在两个数组列表之间使用排序/搜索方法。

错误：

java.io.FileNotFoundException: 3LetterWords.txt (No such file or directory)
    at java.base/java.io.FileInputStream.open0(Native Method)
    at java.base/java.io.FileInputStream.open(FileInputStream.java:216)
    at java.base/java.io.FileInputStream.<init>(FileInputStream.java:157)
    at java.base/java.io.FileInputStream.<init>(FileInputStream.java:111)
    at java.base/java.io.FileReader.<init>(FileReader.java:60)
    at wordleproj.WordleProj.main(WordleProj.java:17)
Exception in thread "main" java.lang.NullPointerException: Cannot invoke "java.io.BufferedReader.close()" because "br" is null
    at wordleproj.WordleProj.main(WordleProj.java:26)
/Users/mac/Library/Caches/NetBeans/12.6/executor-snippets/run.xml:111: The following error occurred while executing this line:
/Users/mac/Library/Caches/NetBeans/12.6/executor-snippets/run.xml:68: Java returned: 1

Answer 1

您需要在项目中创建文件3LetterWords.txt或添加文件路径。

// you don't have the path but only the filename so the file should be in your project.
br = new BufferedReader(new FileReader("3LetterWords.txt"));

或指定路径

br = new BufferedReader(new FileReader("C:\\Users\\Admin\\Downloads\\3LetterWords.txt"));