把一个表的查询结果当做另一个表的一个字段输出

把一个表的查询结果当做另一个表的一个字段输出

CourseController.java

//Controller
@GetMapping("/getPage/{number}/{size}")
    @ApiOperation(value = "分页查询课程表（含已更新章节字段）", tags = {"2020-09-09"})
    @ApiOperationSupport(
            order = 7,
            ignoreParameters = {"createTime", "updateTime"}
    )
    @ResponseBody
    public Result<TabCourseVo> getPage(@PathVariable final int number, @PathVariable final int size, final TabCourse condition) {
        return new Result<TabCourseVo>().execute(result -> result.setSuccess(service.getPage(
                Optional.ofNullable(condition).orElseGet(TabCourse::new),
                Pager.builder().number(number).size(size).build()
        )));
    }

如果number和size不加@PathVariable的话，会出现
500：请求失败，不明确的异常：Optional int parameter ‘number’ is present but cannot be translated into a null value due to being declared as a primitive type. Consider declaring it as object wrapper for the corresponding primitive type
这个错误
如果想传递当前登录的user信息的话需要加上@ApiIgnore @AuthenticationPrincipal注解

CourseService.java

//Service
public QueryResults<TabCourseVo> getPage(final TabCourse condition, final Pager pager) {
        QTabCourseChapter tabCourseChapter = QTabCourseChapter.tabCourseChapter;
        return repository.getPage(condition,Pager.rebuild(pager), TabCourseVo.class,TabCourse.allColumnAppends(
                tabCourseChapter.id.count().as("update_chapters")
        ));
    }

CourseRepository.java

//Repository
default <T> QueryResults<T> getPage(final TabCourse condition, final Pager pager, final Class<T> clazz,final Expression<?>... exps) {
        QTabCourseChapter tabCourseChapter = QTabCourseChapter.tabCourseChapter;
        return jpaQueryFactory.<JPAQueryFactory>get()
                .select(Projections.bean(clazz, exps))
                .from(q)
                .leftJoin(tabCourseChapter)
                .on(q.id.eq(tabCourseChapter.courseId))
                .where(condition.where().toArray())
                .groupBy(q.id)
                .offset(pager.offset())
                .limit(pager.limit())
                .fetchResults();
    }

TabCourseVo.java

//返回值的实体，继承TabCourse并添加update_chapters字段
package com.st.kxy.business.course;

import com.st.kxy.business.course.entity.TabCourse;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.ToString;

@EqualsAndHashCode(callSuper = true)
@ToString
@Data
public class TabCourseVo  extends TabCourse {

    private Long update_chapters;
}