黑马学成在线项目之Day4实战

删除课程计划

课程计划排序：

师资管理，也就是课程教师的信息查询，添加，修改，删除操作

删除课程

总结

删除课程计划

首先观察文档：

我们发现，此时的报错信息中是有个errCode参数的，为了方便使用，我们就可以直接在base工程那个目录下面的XueChengPlusException文件中添加一些参数：

public class XueChengPlusException extends RuntimeException {private String errMessage;private int errCode = 0;public XueChengPlusException() {}public XueChengPlusException(String errMessage) {this.errMessage = errMessage;}public XueChengPlusException(String errMessage,int errCode) {this.errMessage = errMessage;this.errCode = errCode;}public String getErrMessage() {return errMessage;}public int getErrCode(){return errCode;}public void setErrCode(int errCode){this.errCode = errCode;}public static void cast(String errMessage) {throw new XueChengPlusException(errMessage);}public static void cast(String errMessage,int errCode) {throw new XueChengPlusException(errMessage,errCode);}public static void cast(CommonError commonError) {throw new XueChengPlusException(commonError.getErrMessage());}
}

当然，肯定是少不了修改返回给前端的那个参数包装类RestErrorResponse：

public class RestErrorResponse implements Serializable {private String errMessage;private int errCode;public RestErrorResponse(String errMessage){this.errMessage= errMessage;}public RestErrorResponse(String errMessage,int errCode){this.errMessage= errMessage;this.errCode = errCode;}public int getErrCode(){return errCode;}public void setErrCode(int errCode){this.errCode = errCode;}public String getErrMessage() {return errMessage;}public void setErrMessage(String errMessage) {this.errMessage = errMessage;}
}

这两步搞定就可以开始我们的操作了

第一步当然是先在api的TeachplanController中定义接口：

@Api(value = "课程计划编辑接口",tags = "课程计划编辑接口")
@RestController
public class TeachplanController {@AutowiredTeachplanService teachplanService;@ApiOperation("课程计划删除")@DeleteMapping("/teachplan/{courseId}")public void deleteTeachplan(@PathVariable Long courseId){System.out.println("课程计划删除")}}

然后经过考虑发现，其实Mapper中的自定义方法是不满足，一些要求的，就这个删除而言，如果是大章节，那么就要进行大章节下面是否有小章节的判断，所以我们可以在手写一个SQL，所以这边要给TeachplanMapper加入一个，我们自定义判断大章节下面是否有小章节的接口：

public interface TeachplanMapper extends BaseMapper<Teachplan> {//课程计划查询public List<TeachplanDto> selectTreeNodes(Long courseId);//查询大章节下面是否有小章节public Long selectBigFest(Long id);
}

然后去TeachplanMapper.xml中实现我们的SQL，在这里完整的文件我就不写出来了，只写个自定义SQL和方法：

  <select id="selectBigFest"  parameterType="long" resultType="java.lang.Long">SELECTCOUNT(*)FROMteachplan oneINNER JOIN teachplan two ON two.parentid = one.idWHEREone.id = #{id}</select>

在这个接口中，如果大章节下面有数据，就会返回数据的总条数，如果没有数据就会返回0，我们在之后的代码中就可以直接进行判断，

现在在service工程下面找到课程计划的TeachplanService接口，在接口中定义删除课程的方法：

public interface TeachplanService {/***因为删除的时候，是要考虑删除的是大章节还是小章节* 删除课程小节和大章节* @param courseId 课程id*/void deleteTeachplan(Long courseId);
}

然后开始去Service接口的实现类TeachplanServiceImpl中，写逻辑思维：

@Service
public class TeachplanServiceImpl implements TeachplanService {@AutowiredTeachplanMapper teachplanMapper;@AutowiredTeachplanMediaMapper teachplanMediaMapper;public void deleteTeachplan(Long courseId) {//根据courseId查询课程计划，然后通过parentId判断是小章节还是大章节Teachplan teachplan = teachplanMapper.selectById(courseId);if (teachplan.getParentid() != 0) {//证明是小章节//根据mediaType属性判断小章节是否关联视频String mediaType = teachplan.getMediaType();if (mediaType == null) {//证明没有关联视频或者文档//删除小章节teachplanMapper.deleteById(teachplan);} else {//证明关联了视频或者文档//删除视频，暂不考虑文档的情况teachplanMediaMapper.deleteById(courseId);//删除小章节teachplanMapper.deleteById(teachplan);}//} else {//证明是大章节//判断大章节下面是否有小节Long aLong = teachplanMapper.selectBigFest(courseId);if (aLong == 0) {//证明没有小节，可以进行删除teachplanMapper.deleteById(teachplan);} else {//有小节，不能删除XueChengPlusException.cast("课程计划信息还有子级信息，无法操作", 120409);}}}}

然后就可以在Controller接口中，直接调用方法，进行测试，这里我就不写测试过程了，这个已经测试是没问题的：

@Api(value = "课程计划编辑接口",tags = "课程计划编辑接口")
@RestController
public class TeachplanController {@AutowiredTeachplanService teachplanService; @ApiOperation("课程计划删除")@DeleteMapping("/teachplan/{courseId}")public void deleteTeachplan(@PathVariable Long courseId){teachplanService.deleteTeachplan(courseId);}
}

课程计划排序

老规矩先看文档：

看完之后，我们就可以先定义Controller层中的方法了：

@Api(value = "课程计划编辑接口",tags = "课程计划编辑接口")
@RestController
public class TeachplanController {@AutowiredTeachplanService teachplanService;@ApiOperation(("课程计划向下移动"))@PostMapping("/teachplan/movedown/{id}")public void moveDown(@PathVariable Long id){System.out.println("课程计划向下移动")}@ApiOperation(("课程计划向上移动"))@PostMapping("/teachplan/moveup/{id}")public void moveUp(@PathVariable Long id){System.out.println("课程计划向上移动")}}

然后开始定义Service层的接口方法：

public interface TeachplanService {/*** 课程计划向下移动* @param id 课程id*/void moveDown(Long id);/*** 课程计划向上移动* @param id 课程id*/void moveUp(Long id);}

然后开始去实现逻辑：

@Service
public class TeachplanServiceImpl implements TeachplanService {@AutowiredTeachplanMapper teachplanMapper;@AutowiredTeachplanMediaMapper teachplanMediaMapper;public void moveDown(Long id) {//课程计划向下移动//根据courseId查询课程计划，然后通过parentId判断是小章节还是大章节Teachplan teachplan = teachplanMapper.selectById(id);if (teachplan.getParentid() != 0) {Integer orderby = teachplan.getOrderby();//证明是小章节//根据父章节的id，找出大章节下面所有小节点LambdaQueryWrapper<Teachplan> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(Teachplan::getParentid,teachplan.getParentid()).eq(Teachplan::getGrade,2);List<Teachplan> teachplans = teachplanMapper.selectList(queryWrapper);int i = 0;for (Teachplan t:teachplans) {//找到当前章节的排序字段加一,以此获得下一个章节if(t.getOrderby()==orderby+1){i++;}if(i==1){//进行交换teachplan.setOrderby(t.getOrderby());t.setOrderby(orderby);teachplanMapper.updateById(t);teachplanMapper.updateById(teachplan);break;}}if(i==0){XueChengPlusException.cast("当前计划已经在末尾，无法交换");}} else {Integer orderby = teachplan.getOrderby();//证明是大章节//根据课程的id，找到下一个大章节LambdaQueryWrapper<Teachplan> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(Teachplan::getCourseId,teachplan.getCourseId()).eq(Teachplan::getGrade,1);List<Teachplan> teachplans = teachplanMapper.selectList(queryWrapper);int i = 0;for (Teachplan t:teachplans) {//找到当前章节的排序字段加一,以此获得下一个章节if(t.getOrderby()==orderby+1){i++;}if(i==1){//进行交换teachplan.setOrderby(t.getOrderby());t.setOrderby(orderby);teachplanMapper.updateById(t);teachplanMapper.updateById(teachplan);break;}}if(i==0){XueChengPlusException.cast("当前计划已经在末尾，无法交换");}}}@Overridepublic void moveUp(Long id) {//课程计划向上移动//根据courseId查询课程计划，然后通过parentId判断是小章节还是大章节Teachplan teachplan = teachplanMapper.selectById(id);if (teachplan.getParentid() != 0) {Integer orderby = teachplan.getOrderby();//证明是小章节//根据父章节的id，找出大章节下面所有小节点LambdaQueryWrapper<Teachplan> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(Teachplan::getParentid,teachplan.getParentid()).eq(Teachplan::getGrade,2);List<Teachplan> teachplans = teachplanMapper.selectList(queryWrapper);int i = 0;for (Teachplan t:teachplans) {//找到当前章节的排序字段减一,以此获得上一个章节if(t.getOrderby()==orderby-1&&(orderby-1)!=0){i++;}if(i==1){//进行交换teachplan.setOrderby(t.getOrderby());t.setOrderby(orderby);teachplanMapper.updateById(t);teachplanMapper.updateById(teachplan);break;}}if(i==0){XueChengPlusException.cast("当前计划已经在顶部，无法交换");}} else {Integer orderby = teachplan.getOrderby();//证明是大章节//根据课程的id，找到上一个大章节LambdaQueryWrapper<Teachplan> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(Teachplan::getCourseId,teachplan.getCourseId()).eq(Teachplan::getGrade,1);List<Teachplan> teachplans = teachplanMapper.selectList(queryWrapper);int i = 0;for (Teachplan t:teachplans) {//找到当前章节的排序字段减一,以此获得上一个章节if(t.getOrderby()==orderby-1&&(orderby-1)!=0){i++;}if(i==1){//进行交换teachplan.setOrderby(t.getOrderby());t.setOrderby(orderby);teachplanMapper.updateById(t);teachplanMapper.updateById(teachplan);break;}}if(i==0){XueChengPlusException.cast("当前计划已经在顶部，无法交换");}}}
}

然后在Controller的api中，进行方法调用：

@Api(value = "课程计划编辑接口",tags = "课程计划编辑接口")
@RestController
public class TeachplanController {@AutowiredTeachplanService teachplanService; @ApiOperation(("课程计划向下移动"))@PostMapping("/teachplan/movedown/{id}")public void moveDown(@PathVariable Long id){teachplanService.moveDown(id);}@ApiOperation(("课程计划向上移动"))@PostMapping("/teachplan/moveup/{id}")public void moveUp(@PathVariable Long id){teachplanService.moveUp(id);}
}

师资管理，也就是课程教师的信息查询，添加，修改，删除操作

先看接口文档：

然后去Controller层，仔细看，此时我是又定义了一个新的Controller，这些接口中的方法，还没实现可以先写上，然后根据这个定义方法，并且添加和删除我是定义了一个接口，咳咳，偷个懒，定义接口：

@Api(value = "师资信息管理接口",tags = "师资信息管理接口")
@RestController
public class CourseTeacherController {@AutowiredCourseTeacherService courseTeacherService;@ApiOperation("讲师信息查询")@GetMapping("/courseTeacher/list/{courseId}")public List<CourseTeacher> getCourseTeacher(@PathVariable Long courseId){return courseTeacherService.getCourseTeacher(courseId);}@ApiOperation("添加/修改讲师")@PostMapping("/courseTeacher")public CourseTeacher setCourseTeacher(@RequestBody CourseTeacher courseTeacher){return courseTeacherService.setCourseTeacher(courseTeacher);}@ApiOperation("删除讲师")@DeleteMapping("/courseTeacher/course/{courseId}/{id}")public void deleteCourseTeacher(@PathVariable Long courseId,@PathVariable Long id){courseTeacherService.deleteCourseTeacher(courseId,id);}
}

然后去CourseTeacherService，要是没有就创建一个，定义接口方法：

import java.util.List;public interface CourseTeacherService {/*** 查询教师信息* @param courseId 课程id* @return 教师信息*/List<CourseTeacher> getCourseTeacher(Long courseId);/*** 添加教师信息* @param courseTeacher 要添加的信息* @return 返回添加的信息*/CourseTeacher setCourseTeacher(CourseTeacher courseTeacher);//删除教师信息void deleteCourseTeacher(Long courseId, Long id);
}

然后去实现层CourseTeacherServiceImpl：

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.xuecheng.base.exception.XueChengPlusException;
import com.xuecheng.content.mapper.CourseTeacherMapper;
import com.xuecheng.content.model.po.CourseTeacher;
import com.xuecheng.content.service.CourseTeacherService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;@Service
public class CourseTeacherServiceImpl implements CourseTeacherService {@AutowiredCourseTeacherMapper courseTeacherMapper;//查询讲师信息@Overridepublic List<CourseTeacher> getCourseTeacher(Long courseId) {//根据课程id查询讲师信息LambdaQueryWrapper<CourseTeacher> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(CourseTeacher::getCourseId,courseId);return courseTeacherMapper.selectList(queryWrapper);}//添加，修改讲师信息@Overridepublic CourseTeacher setCourseTeacher(CourseTeacher courseTeacher) {//根据id判断是修改还是删除if(courseTeacher.getId()==null){//证明是添加courseTeacher.setCreateDate(LocalDateTime.now());courseTeacherMapper.insert(courseTeacher);return courseTeacherMapper.selectById(courseTeacher);}else{//证明是修改courseTeacherMapper.updateById(courseTeacher);return courseTeacherMapper.selectById(courseTeacher);}}//删除讲师信息@Overridepublic void deleteCourseTeacher(Long courseId, Long id) {LambdaQueryWrapper<CourseTeacher> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(CourseTeacher::getCourseId,courseId).eq(CourseTeacher::getId,id);CourseTeacher courseTeacher = courseTeacherMapper.selectOne(queryWrapper);if(courseTeacher==null){XueChengPlusException.cast("未知错误，请稍后重试");}courseTeacherMapper.deleteById(courseTeacher);}
}

然后这些接口就搞定了

删除课程

先看接口文档：

首先还是在Controller层的CourseBaseInfoController中定义接口：

@Api(value = "课程信息管理接口",tags = "课程信息管理接口")
@RestController
public class CourseBaseInfoController {@AutowiredCourseBaseInfoService courseBaseInfoService;@ApiOperation("删除课程")@DeleteMapping("/course/{courseId}")public void deleteCourseBase(@PathVariable Long courseId){//获取到用户所属机构id，这里就先模拟一个，可以自行更改Long companyId = 22L;courseBaseInfoService.deleteCourseBase(companyId,courseId);}
}

然后开始在CourseBaseInfoService中，定义接口，需要注意的是这里的方法，还要有个机构id参数来进行判断是否是本机构：

public interface CourseBaseInfoService {/*** 删除课程* @param companyId 机构id* @param courseId 课程id*/void deleteCourseBase(Long companyId,Long courseId);}

然后去CourseBaseInfoServiceImpl开始实现逻辑：

@Service
public class CourseBaseInfoServiceImpl implements CourseBaseInfoService {@AutowiredCourseBaseMapper courseBaseMapper;@AutowiredCourseMarketMapper courseMarketMapper;@AutowiredCourseCategoryMapper courseCategoryMapper;@AutowiredTeachplanMapper teachplanMapper;@AutowiredTeachplanMediaMapper teachplanMediaMapper;@AutowiredCourseTeacherMapper courseteacherMapper;public void deleteCourseBase(Long companyId, Long courseId) {//根据id查询课程CourseBase courseBase = courseBaseMapper.selectById(courseId);//判断课程是否是该机构的if (!courseBase.getCompanyId().equals(companyId)) {XueChengPlusException.cast("本机构只能删除本机构课程");}LambdaQueryWrapper<CourseTeacher> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(CourseTeacher::getCourseId, courseId);CourseTeacher courseTeacher = courseteacherMapper.selectOne(queryWrapper);if (courseTeacher != null) {//删除讲师信息courseteacherMapper.deleteById(courseTeacher);}LambdaQueryWrapper<CourseMarket> Wrapper = new LambdaQueryWrapper<>();Wrapper.eq(CourseMarket::getId, courseId);CourseMarket courseMarket = courseMarketMapper.selectOne(Wrapper);if (courseMarket != null) {//删除收费信息courseMarketMapper.deleteById(courseMarket);}LambdaQueryWrapper<TeachplanMedia> wrapper = new LambdaQueryWrapper<>();wrapper.eq(TeachplanMedia::getCourseId, courseId);TeachplanMedia teachplanMedia = teachplanMediaMapper.selectOne(wrapper);if (teachplanMedia != null) {//删除媒资信息courseMarketMapper.deleteById(courseTeacher);}LambdaQueryWrapper<Teachplan> qwrapper = new LambdaQueryWrapper<>();qwrapper.eq(Teachplan::getCourseId, courseId);List<Teachplan> teachplan = teachplanMapper.selectList(qwrapper);if (teachplan != null) {for (Teachplan t:teachplan ) {//删除课程计划teachplanMapper.deleteById(t);}}//删除课程信息courseBaseMapper.deleteById(courseBase);}
}

然后所有内容就搞定了，如果以上所有功能，有任何问题，或者你有任何疑惑，欢迎评论交流

总结

删除课程计划，这个接口小难点，我感觉在于那个判断大章节下面是否有小章节的SQL语句。

课程计划排序，这个接口，难点就在于，比如下移，如果是大章节你要如何拿到下一个大章节的数据，这个搞定就没啥了

师资管理，没啥好说的，就crud就完了

删除课程，没啥难点，就要删仔细，一个一个删除就好了，当然我感觉还有更快的方法，但是我咳咳，懒得想了，要是有大神看到，欢迎指点

最后祝大家，早日上岸，天天无bug