Java基础之删除文本文件中特定行的内容

import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class DeleteBook {

    private String bookDelete;
    String[] bookinf = new String[8];
    String[] bookinf1 = new String[8];

    public void deleteBook() throws IOException {
        File file = new File("书籍.txt");
        FileInputStream intput = new FileInputStream(file);
        BufferedReader reader = new BufferedReader(new InputStreamReader(intput));
        String tempString;//定义一个字符串，每一次读出该行字符串内容
        List<String> list = new ArrayList<>();//定义一个list字符串集合用来储存每一行的字符串信息
        while ((tempString = reader.readLine()) != null) {
            list.add(tempString);
        }
        System.out.println("==========当前书籍有==========");
        //遍历字符串集合
        for (String book : list) {
            bookinf = book.split(",");//将‘,‘作为分隔符，将字符串分隔开存放进入数组中
            System.out.print(bookinf[0] + " ");
        }
        System.out.println("");
        //输入要删除的内容
        System.out.println("请输入要删除的书籍名称：");
        Scanner scanner = new Scanner(System.in);
        bookDelete = scanner.next();

        //查询该用户是否有未归还的书籍，如果存在未归还的书籍，将不能删除该用户的信息
        FileInputStream inputStream = new FileInputStream(file);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        String bookString;
        List<String> bookList = new ArrayList<>();
        while ((bookString = bufferedReader.readLine()) != null) {
            bookList.add(bookString);
        }
        boolean have = false;//是否存在书籍
        for (String borrowUser : bookList) {
            bookinf = borrowUser.split(",");
            //判断书籍是否存在
            if (bookDelete.equals(bookinf[0])) {
                have = true;
            }
            //若该书籍存在，判断书籍对应用户位是否存在用户
            //若对应位用户不为“无”，则表示该书籍有人借出，则无法删除该书籍
            //同时告知管理员（打印）该书籍被哪位用户借出尚未归还
            if (!"无".equals(bookinf[6]) && have) {
                System.out.println("该书籍尚未被用户“" + bookinf[6] + "”归还，请在其归还书籍后再进行操作！");
                return;
            }
        }
        //若书籍不存在，输出相应信息后直接跳出程序
        if (have == false) {
            System.out.println("无法找到该书籍，请重新确认后再进行操作！");
            return;
        }
        for (String delBook : list) {
            bookinf1 = delBook.split(",");
            //找到即将删除的书籍在集合中的位置，将该部分内容从集合中删除，然后清空整个文件
            if (bookDelete.equals(bookinf1[0])) {
                list.remove(delBook);//在集合中删除该行
                FileWriter fd = new FileWriter(file, false);//append传入false表示写入内容时将会覆盖文件中之前存在的内容
                fd.write("");//执行删除操作，写入空内容覆盖之前的内容
                fd.close();
                break;
            }
        }

        //重新遍历一遍更改后的集合，将内容重新写入文件内
        for (String user : list) {
            bookinf1 = user.split(",");
            FileWriter fw = new FileWriter(file, true);//append传入true表示写入内容时将不会覆盖文件中之前存在的内容，将新的内容写在之前内容的后面
            fw.write(bookinf1[0] + "," + bookinf1[1] +
                    "," + bookinf1[2] + "," + bookinf1[3] +
                    "," + bookinf1[4] + "," + bookinf1[5] +
                    "," + bookinf1[6] + "," + bookinf1[7]);//执行重新写入内容的操作，将修改过的集合通过数组读下标后，再重新存写入文件中
            fw.write(System.getProperty("line.separator"));//在段落后添加一个换行符
            fw.close();
        }
        System.out.println("删除成功！");
    }

public static void main(String[] args) throws IOException {
        DeleteBook db = new DeleteBook();
        db.deleteBook();
    }