在线图书借阅平台的设计与实现：Spring Boot 实战

Book.java（图书实体）

package com.student.library.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.time.LocalDateTime;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("book")
public class Book {
    @TableId(type = IdType.AUTO)
    private Long bookNo;
    private String bookName;
    private String author;
    private Long categoryId;
    private String publisher;
    private LocalDateTime publishDate;
    private Integer totalCount;
    private Integer availableCount;
    private String description;
}

（2）DTO 包：数据传输对象

BorrowBookDTO.java（借阅请求）

package com.student.library.dto;

import jakarta.validation.constraints.NotNull;
import lombok.Data;

@Data
public class BorrowBookDTO {
    @NotNull(message = "学生 ID 不能为空")
    private Long studentId;
    
    @NotNull(message = "图书编号不能为空")
    private Long bookNo;
    
    @NotNull(message = "借阅天数不能为空")
    private Integer borrowDays = 30;
}

（3）VO 包：视图对象

BookDetailVO.java（图书详情）

package com.student.library.vo;

import lombok.Data;
import java.time.LocalDateTime;

@Data
public class BookDetailVO {
    private Long bookNo;
    private String bookName;
    private String author;
    private String categoryName;
    private String publisher;
    private LocalDateTime publishDate;
    private Integer availableCount;
    private String description;
    private Boolean canBorrow;
}

（4）Service 包：业务逻辑实现

BorrowServiceImpl.java（借阅服务）

package com.student.library.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.student.library.dto.BorrowBookDTO;
import com.student.library.entity.Book;
import com.student.library.entity.BorrowRecord;
import com.student.library.entity.User;
import com.student.library.mapper.BookMapper;
import com.student.library.mapper.BorrowRecordMapper;
import com.student.library.mapper.UserMapper;
import com.student.library.service.BorrowService;
import com.student.library.vo.BorrowRecordVO;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.util.List;
import java.util.stream.Collectors;

@Slf4j
@Service
@RequiredArgsConstructor
public class BorrowServiceImpl extends ServiceImpl<BorrowRecordMapper, BorrowRecord> implements BorrowService {
    private final BorrowRecordMapper borrowRecordMapper;
    private final BookMapper bookMapper;
    private final UserMapper userMapper;

    @Override
    @Transactional
    public BorrowRecord borrowBook(BorrowBookDTO borrowBookDTO) {
        log.info("学生借阅图书：学生 ID={}, 图书编号={}, 借阅天数={}", 
                 borrowBookDTO.getStudentId(), borrowBookDTO.getBookNo(), borrowBookDTO.getBorrowDays());

        // 1. 校验学生身份
        User student = userMapper.selectById(borrowBookDTO.getStudentId());
        if (student == null || student.getRole() != 0) {
            throw new RuntimeException("无效的学生账号，无法借阅图书");
        }

        // 2. 校验图书状态
        Book book = bookMapper.selectById(borrowBookDTO.getBookNo());
        if (book == null) {
            throw new RuntimeException("该图书不存在");
        }
        if (book.getAvailableCount() <= 0) {
            throw new RuntimeException("该图书已无库存，可尝试预约");
        }

        // 3. 生成借阅记录
        BorrowRecord borrowRecord = new BorrowRecord();
        borrowRecord.setStudentId(borrowBookDTO.getStudentId());
        borrowRecord.setBookNo(borrowBookDTO.getBookNo());
        borrowRecord.setBorrowDate(LocalDate.now());
        borrowRecord.setDueDate(LocalDate.now().plusDays(borrowBookDTO.getBorrowDays()));
        borrowRecord.setReturnStatus(0);

        // 4. 更新库存
        book.setAvailableCount(book.getAvailableCount() - 1);
        bookMapper.updateById(book);

        save(borrowRecord);
        return borrowRecord;
    }

    @Override
    public List<BorrowRecordVO> getStudentBorrowRecords(Long studentId) {
        List<BorrowRecord> recordList = lambdaQuery()
                .eq(BorrowRecord::getStudentId, studentId)
                .eq(BorrowRecord::getReturnStatus, 0)
                .list();

        return recordList.stream().map(record -> {
            BorrowRecordVO vo = new BorrowRecordVO();
            BeanUtils.copyProperties(record, vo);
            Book book = bookMapper.selectById(record.getBookNo());
            vo.setBookName(book.getBookName());
            vo.setAuthor(book.getAuthor());

            long daysLeft = ChronoUnit.DAYS.between(LocalDate.now(), record.getDueDate());
            vo.setDaysLeft((int) daysLeft);
            if (daysLeft < 0) {
                vo.setOverdueReminder("已超期" + (-daysLeft) + "天，请尽快归还");
            } else if (daysLeft <= 3) {
                vo.setOverdueReminder("即将超期，剩余" + daysLeft + "天");
            } else {
                vo.setOverdueReminder("正常借阅中");
            }
            return vo;
        }).collect(Collectors.toList());
    }
}

四、网页展示

前端采用 Bootstrap 实现响应式布局，界面简洁清晰。

1. 图书查询页

支持按书名、作者搜索，左侧分类筛选，中间卡片式展示图书列表。剩余可借数量为 0 时显示红色标签。

2. 借阅记录页

表格形式展示未归还记录，包含超期提醒模块。剩余天数小于 3 天时高亮显示。

3. 图书管理页

管理员专用页面，支持添加、编辑、下架图书。低库存图书会有黄色字体提示。

五、优化与调试

1. 核心优化点

• 密码加密：集成 Spring Security 的 BCrypt 加密，避免明文存储。
• 超期提醒：在 Service 层计算剩余天数，前端根据状态渲染不同颜色。
• 分类管理：补充 Category 模块，支持动态管理图书分类。

2. 常见问题解决

• 数据库连接失败：检查 application.yml 中的数据库密码配置。
• 库存未更新：确保在事务中调用 updateById 更新图书信息。

六、总结

本项目展示了基于 Spring Boot 和 AI 辅助开发的完整流程。通过规范的项目结构和清晰的代码逻辑，实现了图书借阅的核心功能。对于后续迭代，可以考虑增加图书预约功能、对接罚款系统等。AI 工具在减少重复代码编写、规范架构设计方面发挥了重要作用，帮助开发者将精力集中在业务逻辑上。