老师点击每个课程下面的进入班级按钮后，可以查看到选择该课程的学生信息，展示的结果出现在内容模块内，选课学生的班级信息存储在数据库中的class表中，根据我提供的代码和要求，检查各部分的代码，给出改善后的各个部分完整代码（userid为老师id,sid为学生id）

为了实现老师点击“进入班级”按钮后查看选课学生信息的功能，并且展示结果出现在内容模块内，我们需要对现有代码进行一些改进。以下是各个部分的改进后的完整代码：

### 1. 前端部分 (`TeachingCourse.vue`)

<template>
  <div class="common-layout">
    <el-container>
      <el-aside width="130px" class="menu">
        <sidermenu></sidermenu>
      </el-aside>
      <el-container>
        <el-header>
          <div class="header">
            <el-input v-model="searchParams.courseName" placeholder="请输入课程名" class="input-with-select" clearable></el-input>
            <el-button type="primary" @click="handleSearch">搜索</el-button>
            <el-input v-model="searchParams.courseId" placeholder="请输入课程号" class="input-with-select" clearable></el-input>
            <el-button type="primary" @click="handleSearch">搜索</el-button>
          </div>
        </el-header>
        <el-main>
          <!-- 显示课程列表 -->
          <div v-if="courses.length > 0" class="course-list">
            <el-card v-for="course in courses" :key="course.course_id" style="max-width: 480px; margin-bottom: 20px;">
              <template #header>
                <div class="card-header">
                  <span>{{ course.course_name }}</span>
                </div>
              </template>
              <div class="text item">
                <p>课程号: {{ course.course_id }}</p>
                <p>学时: {{ course.class_hours }}</p>
                <p>实验学时: {{ course.laboratory_times }}</p>
                <p>学分: {{ course.credits }}</p>
                <p>任教老师ID: {{ course.userid }}</p>
                <div class="course-info">课程详情：{{ course.course_info }}</div>
              </div>
              <template #footer>
                <el-button type="primary" @click="viewStudents(course)">进入班级</el-button>
                <el-button type="primary">学情管理</el-button>
              </template>
            </el-card>
          </div>
          <div v-else>
            <p>暂无课程信息</p>
          </div>
          <!-- 学生信息展示 -->
          <div v-if="selectedCourse && selectedCourse.students.length > 0" class="students-list">
            <h3>选课学生列表</h3>
            <ul>
              <li v-for="student in selectedCourse.students" :key="student.sid">
                <p>学生ID: {{ student.sid }}</p>
                <p>姓名: {{ student.name }}</p>
              </li>
            </ul>
          </div>
          <div v-else-if="selectedCourse && selectedCourse.students.length === 0">
            <p>暂无选课学生</p>
          </div>
        </el-main>
      </el-container>
    </el-container>
  </div>
</template>

<script lang="ts" setup>
import { ref, onMounted } from 'vue';
import { searchCoursesApi, getClassStudentsApi } from '../axios';
import sidermenu from './sidermenu.vue';
import Swal from 'sweetalert2';

const searchParams = ref({
  courseName: '',
  courseId: '',
  userid: localStorage.getItem('userid') // 从localStorage获取userid
});
const courses = ref([]);
const originalCourses = ref([]);
const selectedCourse = ref(null);

const fetchCourses = async () => {
  try {
    const response = await searchCoursesApi(searchParams.value);
    originalCourses.value = response || [];
    courses.value = response || [];
  } catch (error) {
    console.error('获取课程失败:', error);
    Swal.fire({
      icon: 'error',
      title: '获取课程失败',
      text: '无法连接到服务器'
    });
  }
};

onMounted(fetchCourses);

const handleSearch = async () => {
  try {
    const response = await searchCoursesApi(searchParams.value);
    if (response && response.length > 0) {
      courses.value = response;
    } else {
      courses.value = [];
      Swal.fire({
        icon: 'info',
        title: '课程不存在',
        text: '没有找到与搜索条件匹配的课程'
      });
    }
  } catch (error) {
    console.error('搜索错误:', error);
    Swal.fire({
      icon: 'error',
      title: '搜索失败',
      text: '填写正确的课程号'
    });
  }
};

const viewStudents = async (course) => {
  try {
    const response = await getClassStudentsApi(course.course_id);
    if (response.success) {
      selectedCourse.value = { ...course, students: response.data };
    } else {
      Swal.fire({
        icon: 'error',
        title: '获取学生信息失败',
        text: response.message
      });
    }
  } catch (error) {
    console.error('获取学生信息失败:', error);
    Swal.fire({
      icon: 'error',
      title: '错误',
      text: '获取学生信息失败'
    });
  }
};
</script>

<style scoped>
.menu {
  border-right: 1px solid #545c64;
  height: calc(100vh);
  margin-right: 0;
}
.header {
  height: 100%;
  border-bottom: 1px solid #545c64;
  padding: 0;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 10px;
}
.input-with-select {
  width: 200px;
}
.el-header {
  padding: 0;
  margin: 0;
}
.el-main {
  padding: 0;
}
.el-container {
  padding: 0;
}
.course-list {
  margin-top: 20px;
}
.course-info {
  word-wrap: break-word; /* 确保文本自动换行 */
  white-space: pre-wrap; /* 保持空白符序列 */
  overflow: auto; /* 超出部分显示滚动条 */
}
.students-list {
  margin-top: 20px;
}
</style>

### 2. 后端部分 (`getClassStudentsApi.js`)

let db = require('../db/index');
const mongoose = require('mongoose');

const ClassSchema = new mongoose.Schema({
  course_id: String,
  students: [
    {
      sid: String,
      name: String,
    },
  ],
});

const Class = mongoose.model('Class', ClassSchema);

// 获取课程的学生
app.get('/api/class-students/:courseId', async (req, res) => {
  const { courseId } = req.params;
  try {
    const classData = await Class.findOne({ course_id: courseId });
    if (classData) {
      res.json({ success: true, data: classData.students });
    } else {
      res.json({ success: false, message: '未找到该课程的学生信息' });
    }
  } catch (error) {
    console.error('获取学生信息失败:', error);
    res.status(500).json({ success: false, message: '获取学生信息失败' });
  }
});

### 3. 路由部分 (`router.js`)

const express = require('express');
const router = express.Router();
const login = require('./api/login');
const register = require('./api/register');
const courseSearch = require('./api/courseSearch');
const courseAdd = require('./api/courseAdd');
const studentSearch = require('./api/studentSearch');
const classAddRouter = require('./api/classAdd');
const removeStudentFromClass = require('./api/removeStudentFromClassApi');
const getClassStudents = require('./api/classStudents');

router.post('/api/login', login.post);
router.post('/api/register', register.post);
router.post('/api/search-courses', courseSearch.searchCourses);
router.post('/api/add-course', courseAdd.addCourse);
router.post('/api/check-course-id', courseAdd.checkCourseId);
router.post('/api/studentSearch', studentSearch.studentSearchApi);
router.use('/api/classAdd', classAddRouter);
router.delete('/api/removeStudentFromClass', removeStudentFromClass);
router.get('/api/classStudents/:course_id', getClassStudents);

module.exports = router;

### 4. Axios 部分 (`axios.js`)

import axios from 'axios';

const API_BASE_URL = 'http://localhost:3000';

const login = async (userid, password) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/login`, { userid, password });
    return response.data;
  } catch (error) {
    console.error('Login error:', error);
  }
};

const register = async (userid, password) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/register`, { userid, password });
    return response.data;
  } catch (error) {
    console.error('Registration error:', error);
  }
};

const searchCoursesApi = async (params) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/search-courses`, params);
    return response.data;
  } catch (error) {
    console.error('Error searching courses:', error);
    throw error;
  }
};

const addCourse = async (courseData) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/add-course`, courseData);
    return response.data;
  } catch (error) {
    console.error('Error adding course:', error);
    throw error;
  }
};

const checkCourseId = async (courseId) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/check-course-id`, { courseId });
    return response.data.exists;
  } catch (error) {
    console.error('Error checking course ID:', error);
    throw error;
  }
};

const studentSearchApi = async (params) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/studentSearch`, params);
    return response.data;
  } catch (error) {
    console.error('Error searching courses:', error);
    throw error;
  }
};

const addStudentToClassApi = async (data) => {
  try {
    const response = await axios.post(`${API_BASE_URL}/api/classAdd/addstudentToClass`, data);
    return response.data;
  } catch (error) {
    console.error('Error adding student to class:', error);
    throw error;
  }
};

const removeStudentFromClassApi = async (data) => {
  try {
    const response = await axios.delete(`${API_BASE_URL}/api/removeStudentFromClass`, { data: data });
    return response.data;
  } catch (error) {
    console.error('Error removing student from class:', error);
    throw error;
  }
};

const getClassStudentsApi = async (courseId) => {
  try {
    const response = await axios.get(`${API_BASE_URL}/api/classStudents/${courseId}`);
    return response.data;
  } catch (error) {
    console.error('Error fetching class students:', error);
    throw error;
  }
};

export {
  searchCoursesApi,
  addCourse,
  checkCourseId,
  studentSearchApi,
  addStudentToClassApi,
  removeStudentFromClassApi,
  getClassStudentsApi,
};

以上代码改进了前端和后端的部分，确保老师点击“进入班级”按钮后可以查看选课学生的信息，并且这些信息会展示在内容模块内。