feat: 初始化收支管理系统

src/main/java/com/example/finance/service/CategoryService.java

@@ -0,0 +1,54 @@
+package com.example.finance.service;
+
+import com.example.finance.dto.CategoryRequest;
+import com.example.finance.vo.CategoryVO;
+
+import java.util.List;
+
+/**
+ * 分类服务接口，提供收支分类的增删改查操作。
+ */
+public interface CategoryService {
+
+    /**
+     * 获取用户的所有分类列表
+     *
+     * @param userId 用户ID
+     * @return 分类列表
+     */
+    List<CategoryVO> list(Long userId);
+
+    /**
+     * 按类型（收入/支出）获取用户的分类列表
+     *
+     * @param userId 用户ID
+     * @param type 分类类型（如 INCOME、EXPENSE）
+     * @return 分类列表
+     */
+    List<CategoryVO> listByType(Long userId, String type);
+
+    /**
+     * 创建新分类
+     *
+     * @param userId 用户ID
+     * @param request 分类请求参数（名称、类型、图标等）
+     */
+    void create(Long userId, CategoryRequest request);
+
+    /**
+     * 更新分类信息
+     *
+     * @param userId 用户ID
+     * @param id 分类ID
+     * @param request 分类请求参数
+     */
+    void update(Long userId, Long id, CategoryRequest request);
+
+    /**
+     * 删除分类
+     *
+     * @param userId 用户ID
+     * @param id 分类ID
+     */
+    void delete(Long userId, Long id);
+}

src/main/java/com/example/finance/service/StatisticsService.java

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+package com.example.finance.service;
+
+import com.example.finance.dto.StatisticsQuery;
+import com.example.finance.vo.CategoryStatisticsVO;
+import com.example.finance.vo.MonthlyStatisticsVO;
+import com.example.finance.vo.TrendStatisticsVO;
+
+import java.util.List;
+
+/**
+ * 统计服务接口，提供月度收支统计、分类统计和趋势分析功能。
+ */
+public interface StatisticsService {
+
+    /**
+     * 获取月度收支统计（总收入、总支出、结余、交易笔数）
+     *
+     * @param userId 用户ID
+     * @param query 统计查询条件（年份、月份）
+     * @return 月度统计结果
+     */
+    MonthlyStatisticsVO getMonthlyStatistics(Long userId, StatisticsQuery query);
+
+    /**
+     * 获取分类维度的统计数据（各分类的金额、笔数、占比）
+     *
+     * @param userId 用户ID
+     * @param query 统计查询条件（年份、月份）
+     * @return 分类统计列表
+     */
+    List<CategoryStatisticsVO> getCategoryStatistics(Long userId, StatisticsQuery query);
+
+    /**
+     * 获取每日收支趋势统计数据
+     *
+     * @param userId 用户ID
+     * @param query 统计查询条件（年份、月份）
+     * @return 按日排列的趋势统计列表
+     */
+    List<TrendStatisticsVO> getTrendStatistics(Long userId, StatisticsQuery query);
+}

src/main/java/com/example/finance/service/TransactionService.java

@@ -0,0 +1,67 @@
+package com.example.finance.service;
+
+import com.example.finance.common.PageResult;
+import com.example.finance.dto.TransactionQuery;
+import com.example.finance.dto.TransactionRequest;
+import com.example.finance.vo.TransactionExportVO;
+import com.example.finance.vo.TransactionVO;
+
+import java.util.List;
+
+/**
+ * 交易记录服务接口，提供收支记录的分页查询、增删改操作。
+ */
+public interface TransactionService {
+
+    /**
+     * 分页查询交易记录
+     *
+     * @param userId 用户ID
+     * @param query 查询条件（类型、分类、时间范围、分页参数等）
+     * @return 分页结果
+     */
+    PageResult<TransactionVO> page(Long userId, TransactionQuery query);
+
+    /**
+     * 创建交易记录
+     *
+     * @param userId 用户ID
+     * @param request 交易请求参数（金额、分类、类型等）
+     */
+    void create(Long userId, TransactionRequest request);
+
+    /**
+     * 更新交易记录
+     *
+     * @param userId 用户ID
+     * @param id 交易记录ID
+     * @param request 交易请求参数
+     */
+    void update(Long userId, Long id, TransactionRequest request);
+
+    /**
+     * 删除交易记录
+     *
+     * @param userId 用户ID
+     * @param id 交易记录ID
+     */
+    void delete(Long userId, Long id);
+
+    /**
+     * 导出交易记录
+     *
+     * @param userId 用户ID
+     * @param query 查询条件（类型、分类、时间范围等）
+     * @return 导出视图对象列表
+     */
+    List<TransactionExportVO> export(Long userId, TransactionQuery query);
+
+    /**
+     * 切换单条交易记录的"计入统计"标记
+     *
+     * @param userId 用户ID
+     * @param id 交易记录ID
+     * @param includeInStats 新的标记值
+     */
+    void toggleStats(Long userId, Long id, Boolean includeInStats);
+}

src/main/java/com/example/finance/service/UserService.java

@@ -0,0 +1,35 @@
+package com.example.finance.service;
+
+import com.example.finance.dto.LoginRequest;
+import com.example.finance.dto.RegisterRequest;
+import com.example.finance.vo.LoginVO;
+import com.example.finance.vo.UserVO;
+
+/**
+ * 用户服务接口，提供用户登录、注册和信息查询等操作。
+ */
+public interface UserService {
+
+    /**
+     * 用户登录
+     *
+     * @param request 登录请求参数（用户名、密码）
+     * @return 登录结果，包含 Token 和用户信息
+     */
+    LoginVO login(LoginRequest request);
+
+    /**
+     * 用户注册
+     *
+     * @param request 注册请求参数（用户名、密码、昵称等）
+     */
+    void register(RegisterRequest request);
+
+    /**
+     * 获取用户信息
+     *
+     * @param userId 用户ID
+     * @return 用户信息视图对象
+     */
+    UserVO getUserInfo(Long userId);
+}

src/main/java/com/example/finance/service/impl/CategoryServiceImpl.java

@@ -0,0 +1,129 @@
+package com.example.finance.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.example.finance.common.BusinessException;
+import com.example.finance.dto.CategoryRequest;
+import com.example.finance.entity.Category;
+import com.example.finance.mapper.CategoryMapper;
+import com.example.finance.service.CategoryService;
+import com.example.finance.vo.CategoryVO;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * 分类服务实现类，处理收支分类的增删改查业务逻辑。
+ */
+@Service
+public class CategoryServiceImpl implements CategoryService {
+
+    private final CategoryMapper categoryMapper;
+
+    public CategoryServiceImpl(CategoryMapper categoryMapper) {
+        this.categoryMapper = categoryMapper;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 查询用户所有分类，按排序字段和ID升序排列。
+     */
+    @Override
+    public List<CategoryVO> list(Long userId) {
+        List<Category> categories = categoryMapper.selectList(new LambdaQueryWrapper<Category>()
+                .eq(Category::getUserId, userId)
+                .orderByAsc(Category::getSortOrder)
+                .orderByAsc(Category::getId));
+        return categories.stream().map(this::toVO).collect(Collectors.toList());
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 按分类类型筛选用户分类列表，按排序字段和ID升序排列。
+     */
+    @Override
+    public List<CategoryVO> listByType(Long userId, String type) {
+        List<Category> categories = categoryMapper.selectList(new LambdaQueryWrapper<Category>()
+                .eq(Category::getUserId, userId)
+                .eq(Category::getType, type)
+                .orderByAsc(Category::getSortOrder)
+                .orderByAsc(Category::getId));
+        return categories.stream().map(this::toVO).collect(Collectors.toList());
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 创建新分类，若未指定排序值则默认为0。
+     */
+    @Override
+    @Transactional
+    public void create(Long userId, CategoryRequest request) {
+        Category category = new Category();
+        category.setUserId(userId);
+        category.setName(request.getName());
+        category.setType(request.getType());
+        category.setIcon(request.getIcon());
+        // 排序值未提供时默认为0
+        category.setSortOrder(request.getSortOrder() != null ? request.getSortOrder() : 0);
+        categoryMapper.insert(category);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 更新分类信息，需校验分类归属当前用户。
+     */
+    @Override
+    @Transactional
+    public void update(Long userId, Long id, CategoryRequest request) {
+        Category category = categoryMapper.selectById(id);
+        // 校验分类是否存在且属于当前用户
+        if (category == null || !category.getUserId().equals(userId)) {
+            throw new BusinessException("分类不存在");
+        }
+        category.setName(request.getName());
+        category.setType(request.getType());
+        category.setIcon(request.getIcon());
+        if (request.getSortOrder() != null) {
+            category.setSortOrder(request.getSortOrder());
+        }
+        categoryMapper.updateById(category);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 删除分类，需校验分类归属当前用户。
+     */
+    @Override
+    @Transactional
+    public void delete(Long userId, Long id) {
+        Category category = categoryMapper.selectById(id);
+        // 校验分类是否存在且属于当前用户
+        if (category == null || !category.getUserId().equals(userId)) {
+            throw new BusinessException("分类不存在");
+        }
+        categoryMapper.deleteById(id);
+    }
+
+    /**
+     * 将分类实体转换为视图对象
+     *
+     * @param category 分类实体
+     * @return 分类视图对象
+     */
+    private CategoryVO toVO(Category category) {
+        CategoryVO vo = new CategoryVO();
+        vo.setId(category.getId());
+        vo.setName(category.getName());
+        vo.setType(category.getType());
+        vo.setIcon(category.getIcon());
+        vo.setSortOrder(category.getSortOrder());
+        vo.setCreatedAt(category.getCreatedAt());
+        return vo;
+    }
+}

src/main/java/com/example/finance/service/impl/StatisticsServiceImpl.java

@@ -0,0 +1,189 @@
+package com.example.finance.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.example.finance.dto.StatisticsQuery;
+import com.example.finance.entity.Category;
+import com.example.finance.entity.Transaction;
+import com.example.finance.mapper.CategoryMapper;
+import com.example.finance.mapper.TransactionMapper;
+import com.example.finance.service.StatisticsService;
+import com.example.finance.vo.CategoryStatisticsVO;
+import com.example.finance.vo.MonthlyStatisticsVO;
+import com.example.finance.vo.TrendStatisticsVO;
+import org.springframework.stereotype.Service;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.YearMonth;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * 统计服务实现类，提供月度收支汇总、分类占比分析和每日收支趋势统计等业务逻辑。
+ */
+@Service
+public class StatisticsServiceImpl implements StatisticsService {
+
+    private final TransactionMapper transactionMapper;
+    private final CategoryMapper categoryMapper;
+
+    public StatisticsServiceImpl(TransactionMapper transactionMapper, CategoryMapper categoryMapper) {
+        this.transactionMapper = transactionMapper;
+        this.categoryMapper = categoryMapper;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 遍历指定月份的所有交易记录，分别累加收入和支出，计算结余和交易笔数。
+     */
+    @Override
+    public MonthlyStatisticsVO getMonthlyStatistics(Long userId, StatisticsQuery query) {
+        List<Transaction> transactions = getMonthTransactions(userId, query);
+
+        MonthlyStatisticsVO vo = new MonthlyStatisticsVO();
+        BigDecimal totalIncome = BigDecimal.ZERO;
+        BigDecimal totalExpense = BigDecimal.ZERO;
+
+        // 按交易类型分别累加收入和支出
+        for (Transaction t : transactions) {
+            if ("INCOME".equals(t.getType())) {
+                totalIncome = totalIncome.add(t.getAmount());
+            } else {
+                totalExpense = totalExpense.add(t.getAmount());
+            }
+        }
+
+        vo.setTotalIncome(totalIncome);
+        vo.setTotalExpense(totalExpense);
+        vo.setBalance(totalIncome.subtract(totalExpense));
+        vo.setTransactionCount(transactions.size());
+        return vo;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 按分类ID分组统计交易金额、笔数，并计算各分类占总金额的百分比，结果按金额降序排列。
+     */
+    @Override
+    public List<CategoryStatisticsVO> getCategoryStatistics(Long userId, StatisticsQuery query) {
+        List<Transaction> transactions = getMonthTransactions(userId, query);
+
+        // 按分类ID分组
+        Map<Long, List<Transaction>> grouped = transactions.stream()
+                .collect(Collectors.groupingBy(Transaction::getCategoryId));
+
+        // 批量查询分类信息
+        List<Long> categoryIds = new ArrayList<>(grouped.keySet());
+        Map<Long, Category> categoryMap = Map.of();
+        if (!categoryIds.isEmpty()) {
+            List<Category> categories = categoryMapper.selectBatchIds(categoryIds);
+            categoryMap = categories.stream().collect(Collectors.toMap(Category::getId, c -> c));
+        }
+
+        // 计算总金额，用于后续计算百分比
+        BigDecimal totalAmount = transactions.stream()
+                .map(Transaction::getAmount)
+                .reduce(BigDecimal.ZERO, BigDecimal::add);
+
+        // 构建每个分类的统计结果
+        Map<Long, Category> finalCategoryMap = categoryMap;
+        return grouped.entrySet().stream()
+                .map(entry -> {
+                    List<Transaction> list = entry.getValue();
+                    Category category = finalCategoryMap.get(entry.getKey());
+                    BigDecimal amount = list.stream()
+                            .map(Transaction::getAmount)
+                            .reduce(BigDecimal.ZERO, BigDecimal::add);
+
+                    CategoryStatisticsVO vo = new CategoryStatisticsVO();
+                    vo.setCategoryId(entry.getKey());
+                    vo.setCategoryName(category != null ? category.getName() : "未知");
+                    vo.setCategoryIcon(category != null ? category.getIcon() : "");
+                    vo.setType(category != null ? category.getType() : "");
+                    vo.setAmount(amount);
+                    vo.setCount(list.size());
+                    // 计算占比百分比，保留两位小数，四舍五入
+                    if (totalAmount.compareTo(BigDecimal.ZERO) > 0) {
+                        vo.setPercentage(amount.multiply(BigDecimal.valueOf(100))
+                                .divide(totalAmount, 2, RoundingMode.HALF_UP));
+                    } else {
+                        vo.setPercentage(BigDecimal.ZERO);
+                    }
+                    return vo;
+                })
+                // 按金额降序排列
+                .sorted((a, b) -> b.getAmount().compareTo(a.getAmount()))
+                .collect(Collectors.toList());
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 统计指定月份每天的收入和支出，返回按日期排列的趋势数据列表。
+     */
+    @Override
+    public List<TrendStatisticsVO> getTrendStatistics(Long userId, StatisticsQuery query) {
+        YearMonth yearMonth = YearMonth.of(query.getYear(), query.getMonth());
+        int daysInMonth = yearMonth.lengthOfMonth();
+
+        // 初始化每日收入和支出为零
+        Map<Integer, BigDecimal> incomeMap = new HashMap<>();
+        Map<Integer, BigDecimal> expenseMap = new HashMap<>();
+        for (int i = 1; i <= daysInMonth; i++) {
+            incomeMap.put(i, BigDecimal.ZERO);
+            expenseMap.put(i, BigDecimal.ZERO);
+        }
+
+        // 累加每日交易金额
+        List<Transaction> transactions = getMonthTransactions(userId, query);
+        for (Transaction t : transactions) {
+            int day = t.getTransactionTime().getDayOfMonth();
+            if ("INCOME".equals(t.getType())) {
+                incomeMap.merge(day, t.getAmount(), BigDecimal::add);
+            } else {
+                expenseMap.merge(day, t.getAmount(), BigDecimal::add);
+            }
+        }
+
+        // 组装每日趋势数据
+        List<TrendStatisticsVO> result = new ArrayList<>();
+        for (int i = 1; i <= daysInMonth; i++) {
+            TrendStatisticsVO vo = new TrendStatisticsVO();
+            vo.setDate(String.format("%d-%02d-%02d", query.getYear(), query.getMonth(), i));
+            vo.setIncome(incomeMap.get(i));
+            vo.setExpense(expenseMap.get(i));
+            result.add(vo);
+        }
+        return result;
+    }
+
+    /**
+     * 查询指定月份内用户的所有交易记录（仅包含计入统计的记录）
+     *
+     * @param userId 用户ID
+     * @param query 统计查询条件（年份、月份）
+     * @return 该月份的交易记录列表
+     */
+    private List<Transaction> getMonthTransactions(Long userId, StatisticsQuery query) {
+        YearMonth yearMonth = YearMonth.of(query.getYear(), query.getMonth());
+        // 计算月份的起止时间
+        LocalDateTime startTime = yearMonth.atDay(1).atStartOfDay();
+        LocalDateTime endTime = yearMonth.atEndOfMonth().atTime(LocalTime.MAX);
+
+        return transactionMapper.selectList(new LambdaQueryWrapper<Transaction>()
+                .eq(Transaction::getUserId, userId)
+                .ge(Transaction::getTransactionTime, startTime)
+                .le(Transaction::getTransactionTime, endTime)
+                // 仅统计计入统计的记录（排除借款、账户间转账等）
+                .and(w -> w.eq(Transaction::getIncludeInStats, true)
+                        .or().isNull(Transaction::getIncludeInStats)));
+    }
+}

src/main/java/com/example/finance/service/impl/TransactionServiceImpl.java

@@ -0,0 +1,318 @@
+package com.example.finance.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
+import com.example.finance.common.BusinessException;
+import com.example.finance.common.PageResult;
+import com.example.finance.dto.TransactionQuery;
+import com.example.finance.dto.TransactionRequest;
+import com.example.finance.entity.Category;
+import com.example.finance.entity.Transaction;
+import com.example.finance.mapper.CategoryMapper;
+import com.example.finance.mapper.TransactionMapper;
+import com.example.finance.service.TransactionService;
+import com.example.finance.vo.TransactionExportVO;
+import com.example.finance.vo.TransactionVO;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.util.StringUtils;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * 交易记录服务实现类，处理收支记录的分页查询、创建、更新和删除等业务逻辑。
+ */
+@Service
+public class TransactionServiceImpl implements TransactionService {
+
+    private final TransactionMapper transactionMapper;
+    private final CategoryMapper categoryMapper;
+
+    public TransactionServiceImpl(TransactionMapper transactionMapper, CategoryMapper categoryMapper) {
+        this.transactionMapper = transactionMapper;
+        this.categoryMapper = categoryMapper;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 支持按类型、分类、时间范围进行条件查询，结果按交易时间降序排列，
+     * 同时批量关联分类信息以填充分类名称和图标。
+     */
+    @Override
+    public PageResult<TransactionVO> page(Long userId, TransactionQuery query) {
+        LambdaQueryWrapper<Transaction> wrapper = new LambdaQueryWrapper<>();
+        wrapper.eq(Transaction::getUserId, userId);
+
+        // 按交易类型筛选（多选）
+        if (query.getTypes() != null && !query.getTypes().isEmpty()) {
+            wrapper.in(Transaction::getType, query.getTypes());
+        }
+        // 按分类ID筛选（多选）
+        if (query.getCategoryIds() != null && !query.getCategoryIds().isEmpty()) {
+            wrapper.in(Transaction::getCategoryId, query.getCategoryIds());
+        }
+        // 按起始时间筛选
+        if (StringUtils.hasText(query.getStartTime())) {
+            wrapper.ge(Transaction::getTransactionTime,
+                    LocalDateTime.parse(query.getStartTime(), DateTimeFormatter.ISO_LOCAL_DATE_TIME));
+        }
+        // 按结束时间筛选
+        if (StringUtils.hasText(query.getEndTime())) {
+            wrapper.le(Transaction::getTransactionTime,
+                    LocalDateTime.parse(query.getEndTime(), DateTimeFormatter.ISO_LOCAL_DATE_TIME));
+        }
+        // 按支付方式筛选（多选）
+        if (query.getPaymentMethods() != null && !query.getPaymentMethods().isEmpty()) {
+            wrapper.in(Transaction::getPaymentMethod, query.getPaymentMethods());
+        }
+        // 按是否计入统计筛选
+        if (query.getIncludeInStats() != null) {
+            wrapper.eq(Transaction::getIncludeInStats, query.getIncludeInStats());
+        }
+
+        // 按交易时间降序排列
+        wrapper.orderByDesc(Transaction::getTransactionTime);
+
+        Page<Transaction> page = new Page<>(query.getPage(), query.getSize());
+        Page<Transaction> result = transactionMapper.selectPage(page, wrapper);
+
+        // 批量查询关联的分类信息，避免 N+1 查询问题
+        List<Long> categoryIds = result.getRecords().stream()
+                .map(Transaction::getCategoryId)
+                .distinct()
+                .collect(Collectors.toList());
+
+        Map<Long, Category> categoryMap = Map.of();
+        if (!categoryIds.isEmpty()) {
+            List<Category> categories = categoryMapper.selectBatchIds(categoryIds);
+            categoryMap = categories.stream().collect(Collectors.toMap(Category::getId, c -> c));
+        }
+
+        // 将交易记录转换为视图对象，并填充分类名称和图标
+        Map<Long, Category> finalCategoryMap = categoryMap;
+        List<TransactionVO> voList = result.getRecords().stream()
+                .map(t -> toVO(t, finalCategoryMap.get(t.getCategoryId())))
+                .collect(Collectors.toList());
+
+        return new PageResult<>(voList, result.getTotal(), result.getCurrent(), result.getSize());
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 创建交易记录前需校验分类是否存在且归属当前用户。
+     */
+    @Override
+    @Transactional
+    public void create(Long userId, TransactionRequest request) {
+        // 校验分类是否存在且属于当前用户
+        Category category = categoryMapper.selectById(request.getCategoryId());
+        if (category == null || !category.getUserId().equals(userId)) {
+            throw new BusinessException("分类不存在");
+        }
+
+        Transaction transaction = new Transaction();
+        transaction.setUserId(userId);
+        transaction.setCategoryId(request.getCategoryId());
+        transaction.setType(request.getType());
+        transaction.setAmount(request.getAmount());
+        transaction.setPaymentMethod(request.getPaymentMethod());
+        transaction.setRemark(request.getRemark());
+        transaction.setTransactionTime(request.getTransactionTime());
+        transaction.setIncludeInStats(request.getIncludeInStats() == null ? Boolean.TRUE : request.getIncludeInStats());
+        transactionMapper.insert(transaction);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 更新交易记录前需校验记录归属和分类归属。
+     */
+    @Override
+    @Transactional
+    public void update(Long userId, Long id, TransactionRequest request) {
+        // 校验交易记录是否存在且属于当前用户
+        Transaction transaction = transactionMapper.selectById(id);
+        if (transaction == null || !transaction.getUserId().equals(userId)) {
+            throw new BusinessException("记录不存在");
+        }
+
+        // 校验分类是否存在且属于当前用户
+        Category category = categoryMapper.selectById(request.getCategoryId());
+        if (category == null || !category.getUserId().equals(userId)) {
+            throw new BusinessException("分类不存在");
+        }
+
+        transaction.setCategoryId(request.getCategoryId());
+        transaction.setType(request.getType());
+        transaction.setAmount(request.getAmount());
+        transaction.setPaymentMethod(request.getPaymentMethod());
+        transaction.setRemark(request.getRemark());
+        transaction.setTransactionTime(request.getTransactionTime());
+        transaction.setIncludeInStats(request.getIncludeInStats() == null ? Boolean.TRUE : request.getIncludeInStats());
+        transactionMapper.updateById(transaction);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 删除交易记录前需校验记录归属当前用户。
+     */
+    @Override
+    @Transactional
+    public void delete(Long userId, Long id) {
+        Transaction transaction = transactionMapper.selectById(id);
+        if (transaction == null || !transaction.getUserId().equals(userId)) {
+            throw new BusinessException("记录不存在");
+        }
+        transactionMapper.deleteById(id);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 切换单条交易记录的"计入统计"标记，用于表格中直接开关。
+     */
+    @Override
+    @Transactional
+    public void toggleStats(Long userId, Long id, Boolean includeInStats) {
+        Transaction transaction = transactionMapper.selectById(id);
+        if (transaction == null || !transaction.getUserId().equals(userId)) {
+            throw new BusinessException("记录不存在");
+        }
+        transaction.setIncludeInStats(includeInStats == null ? Boolean.TRUE : includeInStats);
+        transactionMapper.updateById(transaction);
+    }
+
+    /**
+     * 将交易实体和关联分类转换为视图对象
+     *
+     * @param t 交易实体
+     * @param category 关联的分类实体（可为 null）
+     * @return 交易视图对象
+     */
+    private TransactionVO toVO(Transaction t, Category category) {
+        TransactionVO vo = new TransactionVO();
+        vo.setId(t.getId());
+        vo.setCategoryId(t.getCategoryId());
+        vo.setCategoryName(category != null ? category.getName() : "");
+        vo.setCategoryIcon(category != null ? category.getIcon() : "");
+        vo.setType(t.getType());
+        vo.setAmount(t.getAmount());
+        vo.setPaymentMethod(t.getPaymentMethod());
+        vo.setRemark(t.getRemark());
+        vo.setTransactionTime(t.getTransactionTime());
+        vo.setIncludeInStats(t.getIncludeInStats() == null ? Boolean.TRUE : t.getIncludeInStats());
+        vo.setCreatedAt(t.getCreatedAt());
+        return vo;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 根据查询条件导出交易记录，不分页，返回所有匹配的记录。
+     */
+    @Override
+    public List<TransactionExportVO> export(Long userId, TransactionQuery query) {
+        LambdaQueryWrapper<Transaction> wrapper = new LambdaQueryWrapper<>();
+        wrapper.eq(Transaction::getUserId, userId);
+
+        // 按交易类型筛选（多选）
+        if (query.getTypes() != null && !query.getTypes().isEmpty()) {
+            wrapper.in(Transaction::getType, query.getTypes());
+        }
+        // 按分类ID筛选（多选）
+        if (query.getCategoryIds() != null && !query.getCategoryIds().isEmpty()) {
+            wrapper.in(Transaction::getCategoryId, query.getCategoryIds());
+        }
+        // 按起始时间筛选
+        if (StringUtils.hasText(query.getStartTime())) {
+            wrapper.ge(Transaction::getTransactionTime,
+                    LocalDateTime.parse(query.getStartTime(), DateTimeFormatter.ISO_LOCAL_DATE_TIME));
+        }
+        // 按结束时间筛选
+        if (StringUtils.hasText(query.getEndTime())) {
+            wrapper.le(Transaction::getTransactionTime,
+                    LocalDateTime.parse(query.getEndTime(), DateTimeFormatter.ISO_LOCAL_DATE_TIME));
+        }
+        // 按支付方式筛选（多选）
+        if (query.getPaymentMethods() != null && !query.getPaymentMethods().isEmpty()) {
+            wrapper.in(Transaction::getPaymentMethod, query.getPaymentMethods());
+        }
+        // 按是否计入统计筛选
+        if (query.getIncludeInStats() != null) {
+            wrapper.eq(Transaction::getIncludeInStats, query.getIncludeInStats());
+        }
+
+        // 按交易时间降序排列
+        wrapper.orderByDesc(Transaction::getTransactionTime);
+
+        List<Transaction> transactions = transactionMapper.selectList(wrapper);
+
+        // 批量查询关联的分类信息
+        List<Long> categoryIds = transactions.stream()
+                .map(Transaction::getCategoryId)
+                .distinct()
+                .collect(Collectors.toList());
+
+        Map<Long, Category> categoryMap = Map.of();
+        if (!categoryIds.isEmpty()) {
+            List<Category> categories = categoryMapper.selectBatchIds(categoryIds);
+            categoryMap = categories.stream().collect(Collectors.toMap(Category::getId, c -> c));
+        }
+
+        // 转换为导出视图对象
+        Map<Long, Category> finalCategoryMap = categoryMap;
+        return transactions.stream()
+                .map(t -> toExportVO(t, finalCategoryMap.get(t.getCategoryId())))
+                .collect(Collectors.toList());
+    }
+
+    /**
+     * 将交易实体和关联分类转换为导出视图对象
+     *
+     * @param t 交易实体
+     * @param category 关联的分类实体（可为 null）
+     * @return 交易导出视图对象
+     */
+    private TransactionExportVO toExportVO(Transaction t, Category category) {
+        TransactionExportVO vo = new TransactionExportVO();
+        Boolean include = t.getIncludeInStats() == null ? Boolean.TRUE : t.getIncludeInStats();
+        if (include) {
+            vo.setType(t.getType().equals("INCOME") ? "收入" : "支出");
+        } else {
+            vo.setType("不计入统计");
+        }
+        vo.setCategoryName(category != null ? category.getName() : "");
+        vo.setAmount(String.format("%.2f", t.getAmount()));
+        vo.setPaymentMethod(getPaymentMethodLabel(t.getPaymentMethod()));
+        vo.setRemark(t.getRemark() != null ? t.getRemark() : "");
+        vo.setTransactionTime(t.getTransactionTime() != null
+                ? t.getTransactionTime().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"))
+                : "");
+        vo.setIncludeInStats(include ? "是" : "否");
+        return vo;
+    }
+
+    /**
+     * 将支付方式编码转换为中文标签
+     *
+     * @param code 支付方式编码
+     * @return 中文标签
+     */
+    private String getPaymentMethodLabel(String code) {
+        if (code == null) return "";
+        return switch (code) {
+            case "WECHAT" -> "微信";
+            case "ALIPAY" -> "支付宝";
+            case "CASH" -> "现金";
+            case "BANK" -> "银行卡";
+            default -> code;
+        };
+    }
+}

src/main/java/com/example/finance/service/impl/UserServiceImpl.java

@@ -0,0 +1,114 @@
+package com.example.finance.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.example.finance.common.BusinessException;
+import com.example.finance.dto.LoginRequest;
+import com.example.finance.dto.RegisterRequest;
+import com.example.finance.entity.User;
+import com.example.finance.mapper.UserMapper;
+import com.example.finance.service.UserService;
+import com.example.finance.util.JwtUtil;
+import com.example.finance.vo.LoginVO;
+import com.example.finance.vo.UserVO;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * 用户服务实现类，处理用户登录认证、注册和信息查询等业务逻辑。
+ */
+@Service
+public class UserServiceImpl implements UserService {
+
+    private final UserMapper userMapper;
+    private final JwtUtil jwtUtil;
+    private final BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
+
+    public UserServiceImpl(UserMapper userMapper, JwtUtil jwtUtil) {
+        this.userMapper = userMapper;
+        this.jwtUtil = jwtUtil;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 根据用户名查询用户，校验密码后生成 JWT Token 返回。
+     */
+    @Override
+    public LoginVO login(LoginRequest request) {
+        // 根据用户名查询用户
+        User user = userMapper.selectOne(new LambdaQueryWrapper<User>()
+                .eq(User::getUsername, request.getUsername()));
+
+        if (user == null) {
+            throw new BusinessException("用户名或密码错误");
+        }
+
+        // 校验密码是否匹配
+        if (!passwordEncoder.matches(request.getPassword(), user.getPasswordHash())) {
+            throw new BusinessException("用户名或密码错误");
+        }
+
+        // 生成 JWT Token
+        String token = jwtUtil.generateToken(user.getId(), user.getUsername());
+
+        LoginVO vo = new LoginVO();
+        vo.setToken(token);
+        vo.setUser(toUserVO(user));
+        return vo;
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 校验用户名是否已存在，不存在则创建新用户并对密码进行 BCrypt 加密。
+     */
+    @Override
+    @Transactional
+    public void register(RegisterRequest request) {
+        // 检查用户名是否已被注册
+        User existing = userMapper.selectOne(new LambdaQueryWrapper<User>()
+                .eq(User::getUsername, request.getUsername()));
+
+        if (existing != null) {
+            throw new BusinessException("用户名已存在");
+        }
+
+        // 构建新用户并加密密码
+        User user = new User();
+        user.setUsername(request.getUsername());
+        user.setPasswordHash(passwordEncoder.encode(request.getPassword()));
+        // 如果未提供昵称，则使用用户名作为默认昵称
+        user.setNickname(request.getNickname() != null ? request.getNickname() : request.getUsername());
+        userMapper.insert(user);
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * 根据用户ID查询用户信息，不存在则抛出异常。
+     */
+    @Override
+    public UserVO getUserInfo(Long userId) {
+        User user = userMapper.selectById(userId);
+        if (user == null) {
+            throw new BusinessException("用户不存在");
+        }
+        return toUserVO(user);
+    }
+
+    /**
+     * 将用户实体转换为视图对象
+     *
+     * @param user 用户实体
+     * @return 用户视图对象
+     */
+    private UserVO toUserVO(User user) {
+        UserVO vo = new UserVO();
+        vo.setId(user.getId());
+        vo.setUsername(user.getUsername());
+        vo.setNickname(user.getNickname());
+        vo.setCreatedAt(user.getCreatedAt());
+        return vo;
+    }
+}