Java，知道文件是否在文件夹内

import java.io.File;

public class FileSearch {
    public static boolean isFileInFolder(File folder, String targetFileName) {
        if (!folder.exists() || !folder.isDirectory()) {
            return false;
        }
        
        File[] files = folder.listFiles();
        for (File file : files) {
            if (file.isFile() && file.getName().equals(targetFileName)) {
                return true;
            }
            if (file.isDirectory()) {
                if (isFileInFolder(file, targetFileName)) {
                    return true;
                }
            }
        }
        
        return false;
    }
    
    public static void main(String[] args) {
        File folder = new File("path/to/folder");
        String targetFileName = "targetFile.txt";
        boolean result = isFileInFolder(folder, targetFileName);
        
        if (result) {
            System.out.println("文件在文件夹内");
        } else {
            System.out.println("文件不在文件夹内");
        }
    }
}