缓存菜品、套餐、购物车相关功能

一、缓存菜品

通过缓存的方式提高查询性能

1.1问题说明

大量的用户访问导致数据库访问压力增大，造成系统响应慢，用户体验差

1.2 实现思路

优先查询缓存，如果缓存没有再去查询数据库，然后载入缓存

将菜品集合序列化后缓存入redis  key为每个分类的id

1.3 代码开发（缓存菜品）

import com.sky.constant.StatusConstant;
import com.sky.entity.Dish;
import com.sky.result.Result;
import com.sky.service.DishService;
import com.sky.vo.DishVO;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController("userDishController")
@RequestMapping("/user/dish")
@Slf4j
@Api(tags = "C端-菜品浏览接口")
public class DishController {
    @Autowired
    private DishService dishService;
    @Autowired
    private RedisTemplate redisTemplate;

    /**
     * 根据分类id查询菜品
     *
     * @param categoryId
     * @return
     */
    @GetMapping("/list")
    @ApiOperation("根据分类id查询菜品")
    public Result<List<DishVO>> list(Long categoryId) {
        //构造redis中的key，规则：dish_分类id
        String key ="dish_"+categoryId;
        //查询redis中是否存在菜品数据
        List<DishVO> list =(List<DishVO>) redisTemplate.opsForValue().get(key);
        if (list!=null&&list.size()>0){
            //如果存在，直接返回，无需查询数据库
            return Result.success(list);
        }
        //如果不存在，查询数据库，将查询到的数据放入redis中
        Dish dish = new Dish();
        dish.setCategoryId(categoryId);
        dish.setStatus(StatusConstant.ENABLE);//查询起售中的菜品
         list = dishService.listWithFlavor(dish);
         redisTemplate.opsForValue().set(key,list);
         return Result.success(list);
    }

}

1.4 代码开发（清除缓存）

为什么要清除缓存？ 为了保证数据的一致性，数据库修改后，缓存中的数据并没有发生改变，用户再次请求后不会请求到新修改的数据，而是过期的数据所以要清除缓存。

什么时候清除缓存？ 后端修改数据后对缓存进行及时的清除

    /**
     * 统一清除缓存数据
     * @param pattern
     */
    private void cleanCache(String pattern){
        Set keys = redisTemplate.keys(pattern);
        redisTemplate.delete(keys);
    }

    }

 /**
     * 启用禁用菜品
     * @param status
     * @param id
     * @return
     */
    @PostMapping("/status/{status}")
    @ApiOperation("启用禁用菜品")
    public Result startOrStop(@PathVariable Integer status,Long id){
        log.info("启用禁用菜品,{},{}",status,id);
        dishService.startOrStop(status,id);
        //将所有的菜品缓存数据清理掉，所有以dish_开头的key
//        Set keys = redisTemplate.keys("dish_");
//        redisTemplate.delete(keys);
        cleanCache("dish_*");
        return Result.success();
    }

二、缓存套餐（基于SpringCache）

2.1 SpringCache

• 被写死了（没有意义）
  @CachePut(cacheNames ="userCache",key = "abc")//如果使用SpringCache缓存数据，key的生成：userCache::abc            //生成的key 与cacheNames，key有关系 

• 动态生成key  + SpEL表达式
  @CachePut(cacheNames ="userCache",key = "#user.id")//如果使用SpringCache缓存数据，key的生成：userCache::#user.id

2.2 入门案例

1.CachePut：将方法返回值放到缓存中

//    @CachePut(cacheNames ="userCache",key = "#user.id")//如果使用SpringCache缓存数据，key的生成：userCache::abc
    @PostMapping
//    @CachePut(cacheNames = "userCache",key ="#result.id")//对象导航
//    @CachePut(cacheNames = "userCache",key = "#p0.id")//#p0代表第一个参数
//    @CachePut(cacheNames = "userCache",key = "#a0.id")
    @CachePut(cacheNames = "userCache",key = "#root.args[0].id")//#root.args[0]代表第一个参数
    public User save(@RequestBody User user){
        userMapper.insert(user);
        return user;
    }

2.Cacheable：在方法执行前先查询缓存，如果缓存中有该数据，直接返回缓存中的数据。如果没有在方法执行后再将返回值放入缓存中

    @GetMapping
    @Cacheable(cacheNames = "userCache",key = "#id")
    public User getById(Long id){
        User user = userMapper.getById(id);
        return user;
    }

Cacheable 不能使用#result.id这种方式设置key的值 

3.CacheEvict ：将一条或者多条数据从缓存中删除

• 删除单条数据

    @CacheEvict(cacheNames = "userCache",key ="#id" )
    @DeleteMapping
    public void deleteById(Long id){
        userMapper.deleteById(id);
    }

• 删除多条数据（allEntries = true）

    @CacheEvict(cacheNames = "userCache",allEntries = true)
	@DeleteMapping("/delAll")
    public void deleteAll(){
        userMapper.deleteAll();
    }

2.3实现思路

2.4代码开发

import com.sky.constant.StatusConstant;
import com.sky.entity.Setmeal;
import com.sky.result.Result;
import com.sky.service.SetmealService;
import com.sky.vo.DishItemVO;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController("userSetmealController")
@RequestMapping("/user/setmeal")
@Api(tags = "C端-套餐浏览接口")
public class SetmealController {
    @Autowired
    private SetmealService setmealService;

    /**
     * 条件查询
     *
     * @param categoryId
     * @return
     */
    @Cacheable(cacheNames = "setmealCache",key = "#categoryId")//key :setmealCache::100
    @GetMapping("/list")
    @ApiOperation("根据分类id查询套餐")
    public Result<List<Setmeal>> list(Long categoryId) {
        Setmeal setmeal = new Setmeal();
        setmeal.setCategoryId(categoryId);
        setmeal.setStatus(StatusConstant.ENABLE);

        List<Setmeal> list = setmealService.list(setmeal);
        return Result.success(list);
    }

    /**
     * 根据套餐id查询包含的菜品列表
     *
     * @param id
     * @return
     */
    @GetMapping("/dish/{id}")
    @ApiOperation("根据套餐id查询包含的菜品列表")
    public Result<List<DishItemVO>> dishList(@PathVariable("id") Long id) {
        List<DishItemVO> list = setmealService.getDishItemById(id);
        return Result.success(list);
    }
}

import com.github.pagehelper.Page;
import com.sky.dto.SetmealDTO;
import com.sky.dto.SetmealPageQueryDTO;
import com.sky.result.PageResult;
import com.sky.result.Result;
import com.sky.service.SetmealService;
import com.sky.vo.SetmealVO;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.web.bind.annotation.*;

import java.util.List;

/**
 * 套餐管理
 */
@RestController
@RequestMapping("/admin/setmeal")
@Api(tags = "套餐管理相关接口")
@Slf4j
public class SetmealController {
    @Autowired
    private SetmealService setmealService;

    @CacheEvict(cacheNames = "setmealCache",key = "setmealDTO.categoryId")
    @PostMapping
    @ApiOperation("新增套餐接口")
    public Result save(@RequestBody SetmealDTO setmealDTO){
    log.info("新增套餐：{}",setmealDTO);
    setmealService.saveWithDish(setmealDTO);
    return Result.success();
    }

    /**
     * 套餐分页查询
     * @param setmealPageQueryDTO
     * @return
     */

    @GetMapping("/page")
    @ApiOperation("套餐分页查询")
    public Result<PageResult> pageQuery(SetmealPageQueryDTO setmealPageQueryDTO){
    log.info("套餐分页查询：{}",setmealPageQueryDTO);
    PageResult pageResult  = setmealService.pageQuery(setmealPageQueryDTO);
    return Result.success(pageResult);

    }

    /**
     * 批量删除套餐
     * @param ids
     * @return
     */
    @CacheEvict(cacheNames = "setmealCache",allEntries = true)
    @DeleteMapping
    @ApiOperation("批量删除菜品")
    public Result delete(@RequestParam List<Long> ids){
    log.info("批量删除套餐：{}",ids);
    setmealService.deleteBatch(ids);
    return Result.success();
    }
    /**
     * 根据id查询套餐，用于修改页面回显数据
     *
     * @param id
     * @return
     */
    @GetMapping("/{id}")
    @ApiOperation("根据id查询套餐")
    public Result<SetmealVO> getById(@PathVariable Long id) {
        SetmealVO setmealVO = setmealService.getByIdWithDish(id);
        return Result.success(setmealVO);
    }

    /**
     * 修改套餐
     *
     * @param setmealDTO
     * @return
     */
    @CacheEvict(cacheNames = "setmealCache",allEntries = true)
    @PutMapping
    @ApiOperation("修改套餐")
    public Result update(@RequestBody SetmealDTO setmealDTO) {
        setmealService.update(setmealDTO);
        return Result.success();
    }

    /**
     * 套餐起售停售
     * @param status
     * @param id
     * @return
     */
    @CacheEvict(cacheNames = "setmealCache",allEntries = true)
    @PostMapping("/status/{status}")
    @ApiOperation("套餐起售停售")
    public Result startOrStop(@PathVariable Integer status, Long id) {
        setmealService.startOrStop(status, id);
        return Result.success();
    }


}

三、添加购物车

3.1需求分析和设计

3.2 代码开发

3.2.1Controller

import com.sky.dto.ShoppingCartDTO;
import com.sky.result.Result;
import com.sky.service.ShoppingCartService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user/shoppingCart")
@Api(tags = "C端购物车相关接口")
@Slf4j
public class ShoppingCartController {
    @Autowired
    private ShoppingCartService shoppingCartService;
    /**
     * 添加购物车
     * @param shoppingCartDTO
     * @return
     */
    @PostMapping("/add")
    @ApiOperation("添加购物车")
    public Result add(@RequestBody ShoppingCartDTO shoppingCartDTO){
        log.info("添加购物车，商品信息为：",shoppingCartDTO);
        shoppingCartService.addShoppingCart(shoppingCartDTO);
        return Result.success();
    }

}

 3.2.2 Serveice层

import com.sky.context.BaseContext;
import com.sky.dto.ShoppingCartDTO;
import com.sky.entity.Dish;
import com.sky.entity.Setmeal;
import com.sky.entity.ShoppingCart;
import com.sky.mapper.DishMapper;
import com.sky.mapper.SetmealMapper;
import com.sky.mapper.ShoppingCartMapper;
import com.sky.service.ShoppingCartService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.util.List;

@Service
@Slf4j
public class ShoppingCartServiceImpl implements ShoppingCartService {
    @Autowired
    private ShoppingCartMapper shoppingCartMapper;
    @Autowired
    private DishMapper dishMapper;
    @Autowired
    private SetmealMapper setmealMapper;
    /**
     * 添加购物车
     * @param shoppingCartDTO
     */
    @Override
    public void addShoppingCart(ShoppingCartDTO shoppingCartDTO) {
        //判断当前加入到购物车中的商品是否已经存在了
        ShoppingCart shoppingCart = new ShoppingCart();
        BeanUtils.copyProperties(shoppingCartDTO,shoppingCart);
        Long userId = BaseContext.getCurrentId();
        shoppingCart.setUserId(userId);
        List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);
        //如果已经存在了，只需要将其数量加1
        if (list !=null && list.size()>0){
            ShoppingCart cart = list.get(0);
            cart.setNumber(cart.getNumber()+1);
            shoppingCartMapper.updateNumberById(cart);
        }else {
            //如果不存在，需要插入一条购物车数据


            //判断本次添加购物车的是菜品还是套餐
            Long dishId = shoppingCartDTO.getDishId();
            if (dishId !=null){
                //本次添加的是菜品
                Dish dish = dishMapper.getById(dishId);
                shoppingCart.setName(dish.getName());
                shoppingCart.setImage(dish.getImage());
                shoppingCart.setAmount(dish.getPrice());
//                shoppingCart.setNumber(1);
//                shoppingCart.setCreateTime(LocalDateTime.now());
//
            }else {
                //本次添加的是套餐
                Long setmealId = shoppingCartDTO.getSetmealId();
                Setmeal setmeal = setmealMapper.getById(setmealId);
                shoppingCart.setName(setmeal.getName());
                shoppingCart.setImage(setmeal.getImage());
                shoppingCart.setAmount(setmeal.getPrice());
//                shoppingCart.setNumber(1);
//                shoppingCart.setCreateTime(LocalDateTime.now());

            }
            shoppingCart.setNumber(1);
            shoppingCart.setCreateTime(LocalDateTime.now());

            shoppingCartMapper.insert(shoppingCart);

        }





    }
}

四、查看购物车

4.1 需求分析和设计

4.2 代码开发

4.2.1Controller层

/**
     * 查看购物车
     * @return
     */

    @GetMapping("/list")
    @ApiOperation("查看购物车")
    public  Result<List<ShoppingCart>> list(){
    List<ShoppingCart> list = shoppingCartService.showShoppingCart();
    return  Result.success(list);

    }

4.2.2 Service层

    /**
     * 查看购物车
     * @return
     */
    @Override
    public List<ShoppingCart> showShoppingCart() {
        //获取当前微信用户的id
        Long userId = BaseContext.getCurrentId();
        ShoppingCart shoppingCart = ShoppingCart.builder()
                .userId(userId)
                .build();
        List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);

        return list;
    }

五、清空购物车

5.1 需求分析和设计

5.2 代码开发

5.2.1 Controller层

    /**
     * 清空购物车
     * @return
     */
    @DeleteMapping("/clean")
    public  Result clean(){
        shoppingCartService.cleanShoppingCart();
        return Result.success();

    }

5.2.2 Service层

    /**
     * 清空购物车
     */
    @Override
    public void cleanShoppingCart() {
        Long userId = BaseContext.getCurrentId();
        shoppingCartMapper.deleteByUserId(userId);


    }

5.2.3 Mapper层

    /**
     * 根据用户id删除购物车数据
     * @param userId
     */
    @Delete("delete from shopping_cart where user_id =#{userId}")
    void deleteByUserId(Long userId);