在线教育项目-day13【课程列表后端】

1.创建一个vo类，用来封装查询的对象

package com.dm.eduservice.entity.front;

import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

import java.io.Serializable;

@Data
public class CourseQueryVo implements Serializable {
    private static final long serialVersionUID = 1L;

    @ApiModelProperty(value = "课程名称")
    private String title;

    @ApiModelProperty(value = "讲师id")
    private String teacherId;

    @ApiModelProperty(value = "一级类别id")
    private String subjectParentId;

    @ApiModelProperty(value = "二级类别id")
    private String subjectId;

    @ApiModelProperty(value = "销量排序")
    private String buyCountSort;

    @ApiModelProperty(value = "最新时间排序")
    private String gmtCreateSort;

    @ApiModelProperty(value = "价格排序")
    private String priceSort;
}

2.创建一个Controller

书写我们的查询方法

@RestController
@RequestMapping("eduservice/coursefront")
@CrossOrigin
public class CourseFrontController {
    @Autowired
    EduCourseService courseService;
    @PostMapping(value = "{page}/{limit}")
    public R pageList(
            @PathVariable Long page,
            @PathVariable Long limit,
            @RequestBody(required = false) CourseQueryVo courseQuery){
        Page<EduCourse> pageParam = new Page<EduCourse>(page, limit);
        Map<String, Object> map = courseService.pageListWeb(pageParam, courseQuery);
        return  R.OK().data(map);
    }

}

3.书写ServiceImpl里的方法

 @Override
    public Map<String, Object> pageListWeb(Page<EduCourse> pageParam, CourseQueryVo courseQuery) {
        QueryWrapper<EduCourse> queryWrapper = new QueryWrapper<>();
        if (!StringUtils.isEmpty(courseQuery.getSubjectParentId())) {
            queryWrapper.eq("subject_parent_id", courseQuery.getSubjectParentId());
        }

        if (!StringUtils.isEmpty(courseQuery.getSubjectId())) {
            queryWrapper.eq("subject_id", courseQuery.getSubjectId());
        }

        if (!StringUtils.isEmpty(courseQuery.getBuyCountSort())) {
            queryWrapper.orderByDesc("buy_count");
        }

        if (!StringUtils.isEmpty(courseQuery.getGmtCreateSort())) {
            queryWrapper.orderByDesc("gmt_create");
        }

        if (!StringUtils.isEmpty(courseQuery.getPriceSort())) {
            queryWrapper.orderByDesc("price");
        }

        baseMapper.selectPage(pageParam, queryWrapper);

        List<EduCourse> records = pageParam.getRecords();
        long current = pageParam.getCurrent();
        long pages = pageParam.getPages();
        long size = pageParam.getSize();
        long total = pageParam.getTotal();
        boolean hasNext = pageParam.hasNext();
        boolean hasPrevious = pageParam.hasPrevious();

        Map<String, Object> map = new HashMap<String, Object>();
        map.put("items", records);
        map.put("current", current);
        map.put("pages", pages);
        map.put("size", size);
        map.put("total", total);
        map.put("hasNext", hasNext);
        map.put("hasPrevious", hasPrevious);
        return map;
    }