Java-Files：从文本文件中获取特定索引

Question

我有以下目录server/auth/usernames.txt ，我想读取所有行并找到名为clientusername的字符串的特定索引

我有以下一段代码

File dirFile = new File("auth/");
String clientUsername ="john";
int indexUsername = Files.readAllLines(Paths.get(dirFile.getAbsolutePath() + "usernames.txt")).indexOf(clientUsername);

但这给了我server/auth/usernames.txt的完整路径。 我只想得到auth/usernames.txt 。 如何做到这一点？

Answer 1

将dirFile.getAbsolutePath()更改为dirFile.toPath()

Answer 2

public static void main(String[] args) {
    File f = new File("path-to-your-file-on-your-system!");
    System.out.println(getLineNumber("SlimShady", f));
    System.out.println(getLineNumber("Eminem", f));
    System.out.println(getLineNumber("MomsSpaghetti", f));
    System.out.println(getLineNumber("doodoodoodoo....doooooooooo...dooooooo...can't touch this!", f));

}

private static int getLineNumber(String userName, File usernameFile) {
    boolean found = false;
    int lineCount = -1;
    try (BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(usernameFile)))) {            
        String line;
        while ((line = reader.readLine()) != null && !found) {
            ++lineCount; // increment and get (start at 0)
            found = line.trim().equals(userName); // found it?
        }
    } catch (IOException ex) {
        Logger.getLogger(TestMain.class.getName()).log(Level.SEVERE, null, ex);
    }
    if (!found) {
        // we didn't find it... return -1 (an impossible valid value) to handle that scenario.
        lineCount = -1;
    }
    return lineCount; // found it, what line?
    
}

并且在我完全编造的用户名文件中只使用与 Eminem 相关的用户名运行它（我们得到 MC Hammer 的 -1 ......显然我们仍然无法触及它。

run:
1
0
2
-1
BUILD SUCCESSFUL (total time: 0 seconds)