【瑞吉外卖】day05：增、删、改、查分类以及公共字段自动填充（三）

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
 * 分页查询
 * @param page
 * @param pageSize
 * @return
 */
@GetMapping("/page")
public R<Page> page(int page,int pageSize){
    //分页构造器
    Page<Category> pageInfo = new Page<>(page,pageSize);
    //条件构造器
    LambdaQueryWrapper<Category> queryWrapper = new LambdaQueryWrapper<>();
    //添加排序条件，根据sort进行排序
    queryWrapper.orderByAsc(Category::getSort);
    //分页查询
    categoryService.page(pageInfo,queryWrapper);
    return R.success(pageInfo);
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
 * 根据id删除分类
 * @param id
 * @return
 */
@DeleteMapping
public R<String> delete(Long id){
    log.info("删除分类，id为：{}",id);
    categoryService.removeById(id);
    return R.success("分类信息删除成功");
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import lombok.Data;
import java.io.Serializable;
import java.math.BigDecimal;
import java.time.LocalDateTime;
/**
 * 套餐
 */
@Data
public class Setmeal implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    //分类id
    private Long categoryId;
    //套餐名称
    private String name;
    //套餐价格
    private BigDecimal price;
    //状态 0:停用 1:启用
    private Integer status;
    //编码
    private String code;
    //描述信息
    private String description;
    //图片
    private String image;
    @TableField(fill = FieldFill.INSERT)
    private LocalDateTime createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private LocalDateTime updateTime;
    @TableField(fill = FieldFill.INSERT)
    private Long createUser;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Long updateUser;
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.itheima.reggie.entity.Dish;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface DishMapper extends BaseMapper<Dish> {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.itheima.reggie.entity.Setmeal;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface SetmealMapper extends BaseMapper<Setmeal> {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.extension.service.IService;
import com.itheima.reggie.entity.Dish;
public interface DishService extends IService<Dish> {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.extension.service.IService;
import com.itheima.reggie.entity.Setmeal;
public interface SetmealService extends IService<Setmeal> {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.itheima.reggie.entity.Dish;
import com.itheima.reggie.mapper.DishMapper;
import com.itheima.reggie.service.DishService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
@Service
@Slf4j
public class DishServiceImpl extends ServiceImpl<DishMapper,Dish> implements DishService {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.itheima.reggie.entity.Setmeal;
import com.itheima.reggie.mapper.SetmealMapper;
import com.itheima.reggie.service.SetmealService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
@Service
@Slf4j
public class SetmealServiceImpl extends ServiceImpl<SetmealMapper,Setmeal> implements SetmealService {
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
 * 自定义业务异常类
 */
public class CustomException extends RuntimeException {
    public CustomException(String message){
        super(message);
    }
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">public interface CategoryService extends IService<Category> {
  //根据ID删除分类
    public void remove(Long id);
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">@Autowired
private DishService dishService;
@Autowired
private SetmealService setmealService;
/**
 * 根据id删除分类，删除之前需要进行判断
 * @param id
 */
@Override
public void remove(Long id) {
    //添加查询条件，根据分类id进行查询菜品数据
    LambdaQueryWrapper<Dish> dishLambdaQueryWrapper = new LambdaQueryWrapper<>();
    dishLambdaQueryWrapper.eq(Dish::getCategoryId,id);
    int count1 = dishService.count(dishLambdaQueryWrapper);
    //如果已经关联，抛出一个业务异常
    if(count1 > 0){
        throw new CustomException("当前分类下关联了菜品，不能删除");//已经关联菜品，抛出一个业务异常
    }
    //查询当前分类是否关联了套餐，如果已经关联，抛出一个业务异常
    LambdaQueryWrapper<Setmeal> setmealLambdaQueryWrapper = new LambdaQueryWrapper<>();
    setmealLambdaQueryWrapper.eq(Setmeal::getCategoryId,id);
    int count2 = setmealService.count(setmealLambdaQueryWrapper);
    if(count2 > 0){
        throw new CustomException("当前分类下关联了套餐，不能删除");//已经关联套餐，抛出一个业务异常
    }
    //正常删除分类
    super.removeById(id);
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
 * 异常处理方法
 * @return
 */
@ExceptionHandler(CustomException.class)
public R<String> exceptionHandler(CustomException ex){
    log.error(ex.getMessage());
    return R.error(ex.getMessage());
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
* 根据id删除分类
* @param id
* @return
*/
@DeleteMapping
public R<String> delete(Long id){
    log.info("删除分类，id为：{}",id);
    //categoryService.removeById(id);
    categoryService.remove(id);
    return R.success("分类信息删除成功");
}</span></span>

<span style="background-color:#f8f8f8"><span style="color:#333333">/**
 * 根据id修改分类信息
 * @param category
 * @return
 */
@PutMapping
public R<String> update(@RequestBody Category category){
    log.info("修改分类信息：{}",category);
    categoryService.updateById(category);
    return R.success("修改分类信息成功");
}</span></span>