feat(exam): 实现按学生批量生成并下载试题功能

- 增加学生多选功能和生成试题按钮，支持批量操作
- 新增ExamGenerateDialog组件，提供选择年级和难度界面
- 设计后端接口支持多个学生ID，生成对应的试题文档
- 在后端实现批量生成Word文档并压缩打包下载
- 新增StudentDetail业务对象，完善学生信息展示
- 优化了Mapper接口及XML，支持批量查询学生和班级数据
- 提供前端API封装用于调用试题生成和下载服务
- 实现下载失败时的错误处理与提示机制

enlish-vue/src/api/exam.js

@@ -1,4 +1,5 @@
 import axios from "@/axios";
+import { showMessage } from "../composables/util";
 
 export function uploadExamWordsPng(data) {
     return axios.post('/exam/words/submit', data)
@@ -16,3 +17,64 @@ export function getExamWordsDetailResult(id) {
         id: id
     })
 }
+
+export function generateExamWords(data) {
+    return axios.post('/exam/words/generate', data, {
+        // 1. 重要：必须指定响应类型为 blob，否则下载的文件会损坏（乱码）
+        responseType: 'blob',
+        headers: {
+            'Content-Type': 'application/json; application/octet-stream' // 根据需要调整
+        }
+    }).then(response => {
+        // 2. 提取文件名 (处理后端设置的 Content-Disposition)
+        // 后端示例: header("Content-Disposition", "attachment; filename*=UTF-8''" + fileName)
+        let fileName = 'download.zip'; // 默认兜底文件名
+
+        const contentDisposition = response.headers['content-disposition'];
+        if (contentDisposition) {
+            // 正则提取 filename*=utf-8''xxx.zip 或 filename="xxx.zip"
+            const fileNameMatch = contentDisposition.match(/filename\*?=['"]?(?:UTF-\d['"]*)?([^;\r\n"']*)['"]?;?/);
+            if (fileNameMatch && fileNameMatch[1]) {
+                // 后端如果用了 URLEncoder，这里需要 decode
+                fileName = decodeURIComponent(fileNameMatch[1]);
+            }
+        }
+
+        // 3. 开始下载流程
+        resolveBlob(response.data, fileName);
+    }).catch(error => {
+        console.error('下载失败', error);
+        showMessage('下载失败' + error, 'error');
+        // 注意：如果后端报错返回 JSON，因为 responseType 是 blob，
+        // 这里看到的 error.response.data 也是 blob，需要转回文本才能看到错误信息
+        const reader = new FileReader();
+        reader.readAsText(error.response.data);
+        reader.onload = () => {
+            console.log(JSON.parse(reader.result)); // 打印后端实际报错
+        }
+    });
+}
+
+const resolveBlob = (res, fileName) => {
+    // 创建 Blob 对象，可以指定 type，也可以让浏览器自动推断
+    const blob = new Blob([res], { type: 'application/octet-stream' });
+
+    // 兼容 IE/Edge (虽然现在很少用了)
+    if (window.navigator.msSaveOrOpenBlob) {
+        navigator.msSaveBlob(blob, fileName);
+    } else {
+        // 创建一个临时的 URL 指向 Blob
+        const link = document.createElement('a');
+        link.href = window.URL.createObjectURL(blob);
+        link.download = fileName;
+
+        // 触发点击
+        link.style.display = 'none';
+        document.body.appendChild(link);
+        link.click();
+
+        // 清理资源
+        document.body.removeChild(link);
+        window.URL.revokeObjectURL(link.href);
+    }
+};

enlish-vue/src/layouts/components/ExamGenerateDialog.vue

@@ -0,0 +1,94 @@
+<template>
+	<el-dialog v-model="visible" title="生成试题" width="520px" :close-on-click-modal="false">
+		<div class="space-y-4" v-loading="loading">
+			<el-form label-width="80px">
+				<el-form-item label="年级">
+					<el-select v-model="gradeId" placeholder="请选择年级" style="width: 240px">
+						<el-option v-for="g in gradeOptions" :key="g.id" :label="g.title" :value="g.id" />
+					</el-select>
+				</el-form-item>
+				<el-form-item label="难度">
+					<el-select v-model="level" placeholder="请选择难度" style="width: 240px">
+						<el-option :label="'一级'" :value="1" />
+						<el-option :label="'二级'" :value="2" />
+						<el-option :label="'三级'" :value="3" />
+					</el-select>
+				</el-form-item>
+			</el-form>
+			<div class="text-sm text-gray-500">
+				已选学生数量：{{ studentIds.length }}
+			</div>
+		</div>
+		<template #footer>
+			<div class="flex justify-end gap-2">
+				<el-button @click="visible = false">取消</el-button>
+				<el-button type="primary" :disabled="!gradeId || !level" @click="handleGenerate">生成并下载</el-button>
+			</div>
+		</template>
+	</el-dialog>
+</template>
+
+<script setup>
+import { ref, computed, watch, onMounted } from 'vue'
+import { getGradeList } from '@/api/grade'
+import { generateExamWords } from '@/api/exam'
+
+const props = defineProps({
+	modelValue: { type: Boolean, default: false },
+	studentIds: { type: Array, default: () => [] },
+	defaultGradeId: { type: [Number, String], default: null }
+})
+const emit = defineEmits(['update:modelValue'])
+
+const visible = computed({
+	get: () => props.modelValue,
+	set: (val) => emit('update:modelValue', val)
+})
+
+const loading = ref(false)
+const gradeOptions = ref([])
+const gradeId = ref(null)
+const level = ref(null)
+
+async function fetchGrades() {
+	loading.value = true
+	try {
+		const res = await getGradeList(1, 100)
+		const d = res?.data
+		gradeOptions.value = Array.isArray(d?.data) ? d.data : []
+		if (props.defaultGradeId && !gradeId.value) {
+			gradeId.value = Number(props.defaultGradeId)
+		}
+	} finally {
+		loading.value = false
+	}
+}
+
+async function handleGenerate() {
+	if (!gradeId.value || !level.value || props.studentIds.length === 0) return
+	await generateExamWords({
+		gradeId: Number(gradeId.value),
+		level: Number(level.value),
+		studentIds: props.studentIds
+	})
+	ElMessage.success('生成任务已提交，正在下载')
+	visible.value = false
+}
+
+watch(
+	() => props.modelValue,
+	(v) => {
+		if (v) {
+			level.value = null
+			gradeId.value = props.defaultGradeId ? Number(props.defaultGradeId) : null
+			fetchGrades()
+		}
+	}
+)
+
+onMounted(() => {
+	if (visible.value) fetchGrades()
+})
+</script>
+
+<style scoped></style>

enlish-vue/src/pages/class.vue

@@ -35,8 +35,19 @@
                                 selectedGradeId }})</el-tag>
                             <el-button type="primary" @click="fetchStudents">查询</el-button>
                             <el-button @click="resetStudentFilters">重置</el-button>
+                            <el-button type="success" :disabled="selectedStudentIds.length === 0" @click="showGenerateDialog = true">
+                                生成试题
+                            </el-button>
                         </div>
-                        <el-table :data="students" border class="w-full" v-loading="studentLoading">
+                        <el-table
+                            ref="studentTableRef"
+                            :data="students"
+                            border
+                            class="w-full"
+                            v-loading="studentLoading"
+                            @selection-change="onStudentSelectionChange"
+                        >
+                            <el-table-column type="selection" width="48" />
                             <el-table-column prop="id" label="ID" width="80" />
                             <el-table-column prop="name" label="姓名" min-width="120" />
                             <el-table-column prop="classId" label="班级ID" width="100" />
@@ -47,6 +58,11 @@
                                 :total="studentTotalCount" :page-size="studentPageSize" :current-page="studentPageNo"
                                 @current-change="handleStudentPageChange" @size-change="handleStudentSizeChange" />
                         </div>
+                        <ExamGenerateDialog
+                            v-model="showGenerateDialog"
+                            :student-ids="selectedStudentIds"
+                            :default-grade-id="selectedGradeId"
+                        />
                     </div>
 
                     <div class="bg-white dark:bg-gray-800 rounded-lg shadow p-6" v-loading="gradeLoading">
@@ -76,6 +92,7 @@ import { ref, onMounted } from 'vue'
 import { getClassList } from '@/api/class'
 import { getGradeList } from '@/api/grade'
 import { getStudentList } from '@/api/student'
+import ExamGenerateDialog from '@/layouts/components/ExamGenerateDialog.vue'
 
 const classes = ref([])
 const pageNo = ref(1)
@@ -85,6 +102,7 @@ const loading = ref(false)
 const classTableRef = ref(null)
 const selectedClassId = ref(null)
 const selectedClassTitle = ref('')
+
 const grades = ref([])
 const gradePageNo = ref(1)
 const gradePageSize = ref(10)
@@ -93,12 +111,16 @@ const gradeLoading = ref(false)
 const gradeTableRef = ref(null)
 const selectedGradeId = ref(null)
 const selectedGradeTitle = ref('')
+
 const students = ref([])
 const studentPageNo = ref(1)
 const studentPageSize = ref(10)
 const studentTotalCount = ref(0)
 const studentLoading = ref(false)
 const studentName = ref('')
+const studentTableRef = ref(null)
+const selectedStudentIds = ref([])
+const showGenerateDialog = ref(false)
 
 async function fetchClasses() {
     loading.value = true
@@ -178,6 +200,9 @@ function handleStudentSizeChange(s) {
     studentPageNo.value = 1
     fetchStudents()
 }
+function onStudentSelectionChange(rows) {
+    selectedStudentIds.value = rows.map(r => r.id)
+}
 function onClassRowClick(row) {
     selectedClassId.value = row.id
     selectedClassTitle.value = row.title