需求分析

在菜品管理列表页面点击修改按钮，跳转到修改页面，在修改页面回显菜品相关信息并进行修改，在最后点击确定按钮完成修改操作

代码设计

页面发送ajax请求，请求服务端获取分类数据，用于菜品分类下拉框中数据显示
页面发送ajax请求，请求服务端，根据id查询当前菜品信息，用于菜品信息回显
页面发送请求，请求服务端进行图片下载，用于页面图片回显
点击保存按钮，页面发送ajax请求，将修改后的菜品相关数据以json形式提交到服务端

wrong code

@Service
@Slf4j

public class DishServiceImpl extends ServiceImpl<DishMapper, Dish> implements DishService {

    @Autowired
    private DishFlavorService dishFlavorService;
    /**
     * 新增菜品 同时保存对应的口味
     * @param dishDto
     */
    @Transactional //需要加上事务控制 因为涉及到多张表的操作
    public void saveWithFlavor(DishDto dishDto)
    {
        //保存菜品的基本信息到菜品表
        this.save(dishDto);
        Long dishId = dishDto.getId();//给菜品id赋值
        //菜品口味
        List<DishFlavor> flavors = dishDto.getFlavors();
       flavors =  flavors.stream().map((item)->{
            item.setDishId(dishId);
            return  item;
        }).collect(Collectors.toList());
        //保存菜品口味数据到菜品口味表
       dishFlavorService.saveBatch(flavors);

    }

    /**
     * 根据id查询菜品信息以及对应的口味信息
     * @param id
     * @return
     */
    public DishDto getByIdWithFlavor(Long id)
    {
        //查询菜品基本信息 dish
        Dish dish = this.getById(id);

        DishDto dishDto = new DishDto();
        BeanUtils.copyProperties(dish,dishDto);
        //查询当前菜品对应的口味信息 从dish_falvor查询
        LambdaQueryWrapper<DishFlavor> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(DishFlavor::getDishId,dish.getId());
       List<DishFlavor> flavors =  dishFlavorService.list(queryWrapper);
        dishDto.setFlavors(flavors);
        return dishDto;
    }
    @Override
    @Transactional
    public void updateWithFlavor(DishDto dishDto) {
        //更新dish表基本信息
        this.updateById(dishDto);

        //清理当前菜品对应口味数据---dish_flavor表的delete操作
        LambdaQueryWrapper<DishFlavor> queryWrapper = new LambdaQueryWrapper();
        queryWrapper.eq(DishFlavor::getDishId,dishDto.getId());

        dishFlavorService.remove(queryWrapper);

        //添加当前提交过来的口味数据---dish_flavor表的insert操作
        List<DishFlavor> flavors = dishDto.getFlavors();

        flavors = flavors.stream().map((item) -> {
            item.setDishId(dishDto.getId());
            return item;
        }).collect(Collectors.toList());

        dishFlavorService.saveBatch(flavors);
    }


}

/**
 * 菜品管理
 */
@RestController
@RequestMapping("/dish")
@Slf4j
public class DishController {
    @Autowired
    private DishService dishService;//菜品服务
    @Autowired
    private DishFlavorService dishFlavorService;//菜品口味
    @Autowired
    private CategoryService categoryService;//菜品分类
    @PostMapping
    public R<String> save(@RequestBody DishDto dishDto)//记得封装要加RequestBody注解
    {
        log.info(dishDto.toString());
        dishService.saveWithFlavor(dishDto);
        return R.success("新增菜品成功...");
    }

    /**
     * 菜品信息分页查询
     * @param page
     * @param pageSize
     * @param name
     * @return
     */

    @GetMapping("/page")
    public R<Page> page(int page, int pageSize,String name)
    {
        //构造分页构造器对象
        Page<Dish> pageInfo = new Page<>(page,pageSize);
        Page<DishDto> dishDtoPage = new Page<>();

        //条件构造器
        LambdaQueryWrapper<Dish> queryWrapper = new LambdaQueryWrapper<>();
        //添加过滤条件
        //使用模糊查询
        queryWrapper.like(name != null,Dish::getName,name);
        //添加排序条件 根据更新时间进行降序排序
        queryWrapper.orderByDesc(Dish::getUpdateTime);
        //执行分页查询
        dishService.page(pageInfo,queryWrapper);
        //将上面pageInfo对象中的属性拷贝到dishDtoPage中去
        BeanUtils.copyProperties(pageInfo,dishDtoPage,"records");
        List<Dish> records = pageInfo.getRecords();
       List<DishDto> list =  records.stream().map((item)->{
            DishDto dishDto = new DishDto();
            BeanUtils.copyProperties(item,dishDto);
         Long categoryId  =  item.getCategoryId();//分类id
            //根据id查询分类对象
        Category category =  categoryService.getById(categoryId);
        if(category != null)
        {
            String categoryName = category.getName();
            dishDto.setCategoryName(categoryName);
        }
           return  dishDto;
         //String categoryName = category.getName();
         //dishDto.setCategoryName(categoryName);
       // return  dishDto;
        }).collect(Collectors.toList());
      //  List<DishDto> list = null;

        dishDtoPage.setRecords(list);
        return R.success(dishDtoPage);
    }

    /**
     * 根据id查询菜品信息和对应的口味信息
     * @param id
     * @return
     */

    @GetMapping("/id")
    public R<DishDto> get(@PathVariable  Long id)
    {
        DishDto dishDto = dishService.getByIdWithFlavor(id);
        return R.success(dishDto);
    }

    /**
     * 修改菜品
     * @param dishDto
     * @return
     */
    @PutMapping
    public R<String> update(@RequestBody DishDto dishDto)
    {
        log.info(dishDto.toString());
        dishService.updateWithFlavor(dishDto);

        return R.success("修改菜品成功...");
    }

}

找了很久找不到错误，直接用现成的了。。。
在这里插入图片描述

package com.springboot.reggie.controller;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.springboot.reggie.common.R;
import com.springboot.reggie.entity.Employee;
import com.springboot.reggie.service.EmployeeService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.DigestUtils;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletRequest;
import java.time.LocalDateTime;

@Slf4j
@RestController
@RequestMapping("/employee")
public class EmployeeController {

    @Autowired
    private EmployeeService employeeService;

    /**
     * 员工登录
     * @param request
     * @param employee
     * @return
     */
    @PostMapping("/login")
    public R<Employee> login(HttpServletRequest request,@RequestBody Employee employee){

        //1、将页面提交的密码password进行md5加密处理
        String password = employee.getPassword();
        password = DigestUtils.md5DigestAsHex(password.getBytes());

        //2、根据页面提交的用户名username查询数据库
        LambdaQueryWrapper<Employee> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(Employee::getUsername,employee.getUsername());
        Employee emp = employeeService.getOne(queryWrapper);

        //3、如果没有查询到则返回登录失败结果
        if(emp == null){
            return R.error("登录失败");
        }

        //4、密码比对，如果不一致则返回登录失败结果
        if(!emp.getPassword().equals(password)){
            return R.error("登录失败");
        }

        //5、查看员工状态，如果为已禁用状态，则返回员工已禁用结果
        if(emp.getStatus() == 0){
            return R.error("账号已禁用");
        }

        //6、登录成功，将员工id存入Session并返回登录成功结果
        request.getSession().setAttribute("employee",emp.getId());
        return R.success(emp);
    }

    /**
     * 员工退出
     * @param request
     * @return
     */
    @PostMapping("/logout")
    public R<String> logout(HttpServletRequest request){
        //清理Session中保存的当前登录员工的id
        request.getSession().removeAttribute("employee");
        return R.success("退出成功");
    }

    /**
     * 新增员工
     * @param employee
     * @return
     */
    @PostMapping
    public R<String> save(HttpServletRequest request,@RequestBody Employee employee){
        log.info("新增员工，员工信息：{}",employee.toString());

        //设置初始密码123456，需要进行md5加密处理
        employee.setPassword(DigestUtils.md5DigestAsHex("123456".getBytes()));

       // employee.setCreateTime(LocalDateTime.now());
        //employee.setUpdateTime(LocalDateTime.now());

        //获得当前登录用户的id
        //Long empId = (Long) request.getSession().getAttribute("employee");

        //employee.setCreateUser(empId);
        //employee.setUpdateUser(empId);

        employeeService.save(employee);

        return R.success("新增员工成功");
    }

    /**
     * 员工信息分页查询
     * @param page
     * @param pageSize
     * @param name
     * @return
     */
    @GetMapping("/page")
    public R<Page> page(int page,int pageSize,String name){
        log.info("page = {},pageSize = {},name = {}" ,page,pageSize,name);

        //构造分页构造器
        Page pageInfo = new Page(page,pageSize);

        //构造条件构造器
        LambdaQueryWrapper<Employee> queryWrapper = new LambdaQueryWrapper();
        //添加过滤条件
        queryWrapper.like(StringUtils.isNotEmpty(name),Employee::getName,name);
        //添加排序条件
        queryWrapper.orderByDesc(Employee::getUpdateTime);

        //执行查询
        employeeService.page(pageInfo,queryWrapper);

        return R.success(pageInfo);
    }

    /**
     * 根据id修改员工信息
     * @param employee
     * @return
     */
    @PutMapping
    public R<String> update(HttpServletRequest request,@RequestBody Employee employee){
        log.info(employee.toString());

        //Long empId = (Long)request.getSession().getAttribute("employee");
       // employee.setUpdateTime(LocalDateTime.now());
        //employee.setUpdateUser(empId);
        employeeService.updateById(employee);

        return R.success("员工信息修改成功");
    }

    /**
     * 根据id查询员工信息
     * @param id
     * @return
     */
    @GetMapping("/{id}")
    public R<Employee> getById(@PathVariable Long id){
        log.info("根据id查询员工信息...");
        Employee employee = employeeService.getById(id);
        if(employee != null){
            return R.success(employee);
        }
        return R.error("没有查询到对应员工信息");
    }
}

package com.springboot.reggie.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.springboot.reggie.dto.DishDto;
import com.springboot.reggie.entity.Dish;
import com.springboot.reggie.entity.DishFlavor;
import com.springboot.reggie.mapper.DishMapper;
import com.springboot.reggie.service.DishFlavorService;
import com.springboot.reggie.service.DishService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;
import java.util.stream.Collectors;

@Service
@Slf4j
public class DishServiceImpl extends ServiceImpl<DishMapper,Dish> implements DishService {

    @Autowired
    private DishFlavorService dishFlavorService;

    /**
     * 新增菜品，同时保存对应的口味数据
     * @param dishDto
     */
    @Transactional
    public void saveWithFlavor(DishDto dishDto) {
        //保存菜品的基本信息到菜品表dish
        this.save(dishDto);

        Long dishId = dishDto.getId();//菜品id

        //菜品口味
        List<DishFlavor> flavors = dishDto.getFlavors();
        flavors = flavors.stream().map((item) -> {
            item.setDishId(dishId);
            return item;
        }).collect(Collectors.toList());

        //保存菜品口味数据到菜品口味表dish_flavor
        dishFlavorService.saveBatch(flavors);

    }

    /**
     * 根据id查询菜品信息和对应的口味信息
     * @param id
     * @return
     */
    public DishDto getByIdWithFlavor(Long id) {
        //查询菜品基本信息，从dish表查询
        Dish dish = this.getById(id);

        DishDto dishDto = new DishDto();
        BeanUtils.copyProperties(dish,dishDto);

        //查询当前菜品对应的口味信息，从dish_flavor表查询
        LambdaQueryWrapper<DishFlavor> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(DishFlavor::getDishId,dish.getId());
        List<DishFlavor> flavors = dishFlavorService.list(queryWrapper);
        dishDto.setFlavors(flavors);

        return dishDto;
    }

    @Override
    @Transactional
    public void updateWithFlavor(DishDto dishDto) {
        //更新dish表基本信息
        this.updateById(dishDto);

        //清理当前菜品对应口味数据---dish_flavor表的delete操作
        LambdaQueryWrapper<DishFlavor> queryWrapper = new LambdaQueryWrapper();
        queryWrapper.eq(DishFlavor::getDishId,dishDto.getId());

        dishFlavorService.remove(queryWrapper);

        //添加当前提交过来的口味数据---dish_flavor表的insert操作
        List<DishFlavor> flavors = dishDto.getFlavors();

        flavors = flavors.stream().map((item) -> {
            item.setDishId(dishDto.getId());
            return item;
        }).collect(Collectors.toList());

        dishFlavorService.saveBatch(flavors);
    }
}