mabitis-plus查询所有 service controller mapper分别写什么

好的，我来为您分别编写Mybatis-Plus查询所有分类的service、controller、mapper代码。

1. Service层代码：

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.demo.entity.Category;
import com.example.demo.mapper.CategoryMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class CategoryService {

    @Autowired
    private CategoryMapper categoryMapper;

    public List<Category> getAllCategories() {
        QueryWrapper<Category> queryWrapper = new QueryWrapper<>();
        List<Category> categoryList = categoryMapper.selectList(queryWrapper);
        return categoryList;
    }
}

2. Controller层代码：

import com.example.demo.entity.Category;
import com.example.demo.service.CategoryService;
import org.springframework.beans.factory.annotation.Autowired;
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
@RequestMapping("/category")
public class CategoryController {

    @Autowired
    private CategoryService categoryService;

    @GetMapping("/list")
    public List<Category> getAllCategories() {
        return categoryService.getAllCategories();
    }
}

3. Mapper层代码：

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.entity.Category;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface CategoryMapper extends BaseMapper<Category> {
}

在上述代码中，我们使用了Mybatis-Plus提供的BaseMapper接口，并传入了Category实体类作为泛型参数，来实现对Category表的基本增删改查操作。同时，我们在Mapper接口上使用了@Mapper注解，来声明这是一个Mapper接口。