从文件中读取输入流将打印缺少的字符

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class MissingCharacters {
    public static void main(String[] args) {
        File file = new File("input.txt"); // 替换为实际的文件路径

        try (FileInputStream fis = new FileInputStream(file)) {
            StringBuilder sb = new StringBuilder();
            int data;
            while ((data = fis.read()) != -1) {
                sb.append((char) data);
            }

            String content = sb.toString();
            String expectedCharacters = "abcdefghijklmnopqrstuvwxyz"; // 期望的字符

            for (char c : expectedCharacters.toCharArray()) {
                if (content.indexOf(c) == -1) {
                    System.out.println("缺失的字符：" + c);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}