Mooc项目开发笔记（十七）：课程列表的显示前后端实现、课程信息删除前后端实现

一、课程列表的显示后端实现

1、定义搜索对象

在vo包下创建CourseQuery.class类，内容如下：

@ApiModel(value = "Course查询对象", description = "课程查询对象封装")
@Data
public class CourseQuery 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 topSubjectId;

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

    @ApiModelProperty(value = "是否已经发布")
    private String status;

}

2、定义service方法

接口

void pageQuery(Page<EduCourse> page, CourseQuery courseQuery);

实现

    /**
     * 分页加条件查询课程信息
     * @param page
     * @param courseQuery
     */
    @Override
    public void pageQuery(Page<EduCourse> page, CourseQuery courseQuery) {
        QueryWrapper<EduCourse> wrapper = new QueryWrapper<>();
        //构造条件
        if (courseQuery != null) {
            String title = courseQuery.getTitle();
            String status = courseQuery.getStatus();
            String teacherId = courseQuery.getTeacherId();
            String topSubjectId = courseQuery.getTopSubjectId();
            String subSubjectId = courseQuery.getSubSubjectId();

            if (title != null) {
                wrapper.like("title", title);
            }
            if (status != null) {
                wrapper.eq("status", status);
            }
            if (teacherId != null){
                wrapper.eq("teacher_id", teacherId);
            }
            if (topSubjectId != null){
                wrapper.eq("subject_id", topSubjectId);
            }
            if (subSubjectId != null){
                wrapper.eq("subject_parent_id", subSubjectId);
            }
        }
        //进行查询，结果存储在page中
        this.page(page, wrapper);
    }

3、定义web层方法

@ApiOperation(value = "分页条件查询课程信息")
@GetMapping("pageQuery/{cur}/{limit}")
public R pageQuery(@PathVariable("cur") Integer cur,
                   @PathVariable("limit") Integer limit,
                   @RequestBody CourseQuery courseQuery){
    Page<EduCourse> page = new Page<>(cur, limit);

    courseService.pageQuery(page, courseQuery);

    List<EduCourse> list = page.getRecords();

    long total = page.getTotal();

    return R.ok().data("total", total).data("list", list);
}

二、课程列表的显示前端实现

1、定义api

course.js

getPageList(page, limit, searchObj) {
  return request({
    url: `${api_name}/${page}/${limit}`,
    method: 'get',
    params: searchObj
  })
},

2、组件中的js

src/views/edu/list.vue

<script>
import course from '@/api/edu/course'
import teacher from '@/api/edu/teacher'
import subject from '@/api/edu/subject'
export default {
  data() {
    return {
      listLoading: true, // 是否显示loading信息
      list: null, // 数据列表
      total: 0, // 总记录数
      page: 1, // 页码
      limit: 10, // 每页记录数
      searchObj: {
        subjectParentId: '',
        subjectId: '',
        title: '',
        teacherId: ''
      }, // 查询条件
      teacherList: [], // 讲师列表
      subjectNestedList: [], // 一级分类列表
      subSubjectList: [] // 二级分类列表,
    }
  },
  created() { // 当页面加载时获取数据
    this.fetchData()
    // 初始化分类列表
    this.initSubjectList()
    // 获取讲师列表
    this.initTeacherList()
  },
  methods: {
    fetchData(page = 1) { // 调用api层获取数据库中的数据
      console.log('加载列表')
      // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
      // 解决分页无效问题
      this.page = page
      this.listLoading = true
      course.getPageList(this.page, this.limit, this.searchObj).then(response => {
        // debugger 设置断点调试
        if (response.success === true) {
          this.list = response.data.rows
          this.total = response.data.total
        }
        this.listLoading = false
      })
    },
    initTeacherList() {
      teacher.getList().then(response => {
        this.teacherList = response.data.items
      })
    },
    initSubjectList() {
      subject.getNestedTreeList().then(response => {
        this.subjectNestedList = response.data.items
      })
    },
    subjectLevelOneChanged(value) {
      for (let i = 0; i < this.subjectNestedList.length; i++) {
        if (this.subjectNestedList[i].id === value) {
          this.subSubjectList = this.subjectNestedList[i].children
          this.searchObj.subjectId = ''
        }
      }
    },
    resetData() {
      this.searchObj = {}
      this.subSubjectList = [] // 二级分类列表
      this.fetchData()
    }
  }
}
</script>

3、组件模板

查询表单

<el-form :inline="true" class="demo-form-inline">
  
  
  <el-form-item label="课程类别">
    <el-select
      v-model="searchObj.subjectParentId"
      placeholder="请选择"
      @change="subjectLevelOneChanged">
      <el-option
        v-for="subject in subjectNestedList"
        :key="subject.id"
        :label="subject.title"
        :value="subject.id"/>
    el-select>
    
    <el-select v-model="searchObj.subjectId" placeholder="请选择">
      <el-option
        v-for="subject in subSubjectList"
        :key="subject.id"
        :label="subject.title"
        :value="subject.id"/>
    el-select>
  el-form-item>
  
  <el-form-item>
    <el-input v-model="searchObj.title" placeholder="课程标题"/>
  el-form-item>
  
  <el-form-item>
    <el-select
      v-model="searchObj.teacherId"
      placeholder="请选择讲师">
      <el-option
        v-for="teacher in teacherList"
        :key="teacher.id"
        :label="teacher.name"
        :value="teacher.id"/>
    el-select>
  el-form-item>
  <el-button type="primary" icon="el-icon-search" @click="fetchData()">查询el-button>
  <el-button type="default" @click="resetData()">清空el-button>
el-form>

表格和分页

表格添加了 row-class-name=“myClassList” 样式定义

<el-table
  v-loading="listLoading"
  :data="list"
  element-loading-text="数据加载中"
  border
  fit
  highlight-current-row
  row-class-name="myClassList">
  <el-table-column
    label="序号"
    width="70"
    align="center">
    <template slot-scope="scope">
      {{ (page - 1) * limit + scope.$index + 1 }}
    template>
  el-table-column>
  <el-table-column label="课程信息" width="470" align="center">
    <template slot-scope="scope">
      <div class="info">
        <div class="pic">
          <img :src="scope.row.cover" alt="scope.row.title" width="150px">
        div>
        <div class="title">
          <a href="">{{ scope.row.title }}a>
          <p>{{ scope.row.lessonNum }}课时p>
        div>
      div>
    template>
  el-table-column>
  <el-table-column label="创建时间" align="center">
    <template slot-scope="scope">
      {{ scope.row.gmtCreate.substr(0, 10) }}
    template>
  el-table-column>
  <el-table-column label="发布时间" align="center">
    <template slot-scope="scope">
      {{ scope.row.gmtModified.substr(0, 10) }}
    template>
  el-table-column>
  <el-table-column label="价格" width="100" align="center" >
    <template slot-scope="scope">
      {{ Number(scope.row.price) === 0 ? '免费' :
      '¥' + scope.row.price.toFixed(2) }}
    template>
  el-table-column>
  <el-table-column prop="buyCount" label="付费学员" width="100" align="center" >
    <template slot-scope="scope">
      {{ scope.row.buyCount }}人
    template>
  el-table-column>
  <el-table-column label="操作" width="150" align="center">
    <template slot-scope="scope">
      <router-link :to="'/edu/course/info/'+scope.row.id">
        <el-button type="text" size="mini" icon="el-icon-edit">编辑课程信息el-button>
      router-link>
      <router-link :to="'/edu/course/chapter/'+scope.row.id">
        <el-button type="text" size="mini" icon="el-icon-edit">编辑课程大纲el-button>
      router-link>
      <el-button type="text" size="mini" icon="el-icon-delete">删除el-button>
    template>
  el-table-column>
el-table>

<el-pagination
  :current-page="page"
  :page-size="limit"
  :total="total"
  style="padding: 30px 0; text-align: center;"
  layout="total, prev, pager, next, jumper"
  @current-change="fetchData"
/>

4、css的定义