public ResponseEntity<?> update(@RequestBody Knowledge knowledge) { knowledgeService.updateById(knowledge); return BaseResult.ok("保存成功");逐句代码讲解

<think>根据提供的项目结构，我们将逐个实现controller层的代码文件。每个controller将使用Spring Boot的RestController注解，并注入相应的service。 注意：以下代码示例中，我们假设每个Service接口已经定义，并且我们将使用构造函数注入（推荐方式）。 1. AiController.java: 处理与大模型交互相关的请求 2. ContentController.java: 处理课程内容管理相关请求 3. CourseController.java: 处理课程管理相关请求（如课程计划） 4. ExerciseController.java: 处理习题生成和管理的请求 5. AnalysisController.java: 处理学情分析请求 6. KnowledgeController.java: 处理知识库管理请求（新增） 我们将按照这个顺序给出代码。注意，为了简洁，我们省略了部分非核心代码（如详细的日志、部分异常处理等），实际开发中应补充完整。</think>### Controller 层代码实现 #### 1. AiController.java - AI接口控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.dto.AiRequest; import com.example.teacherassistant.model.dto.TeachingPlanDto; import com.example.teacherassistant.service.AiService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; @RestController @RequestMapping("/api/ai") public class AiController { private final AiService aiService; @Autowired public AiController(AiService aiService) { this.aiService = aiService; } // 生成课程设计内容 @PostMapping("/course-design") public ResponseEntity<String> generateCourseDesign(@RequestBody TeachingPlanDto planDto) { String designContent = aiService.generateCourseDesign( planDto.getSubject(), planDto.getKnowledgePoints() ); return ResponseEntity.ok(designContent); } // 生成教学计划 @PostMapping("/teaching-plan") public ResponseEntity<TeachingPlanDto> generateTeachingPlan(@RequestBody AiRequest request) { TeachingPlanDto plan = aiService.generateTeachingPlan( request.getSubject(), request.getKeywords() ); return ResponseEntity.ok(plan); } // 分析学生答案 @PostMapping("/analyze-answer") public ResponseEntity<String> analyzeStudentAnswer( @RequestParam String question, @RequestParam String studentAnswer, @RequestParam String correctAnswer) { String analysis = aiService.analyzeAnswer(question, studentAnswer, correctAnswer); return ResponseEntity.ok(analysis); } } ``` #### 2. ContentController.java - 内容管理控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.entity.Courseware; import com.example.teacherassistant.service.ContentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import org.springframework.web.multipart.MultipartFile; import java.util.List; @RestController @RequestMapping("/api/content") public class ContentController { private final ContentService contentService; @Autowired public ContentController(ContentService contentService) { this.contentService = contentService; } // 创建课程内容 @PostMapping public ResponseEntity<Courseware> createCourseContent( @RequestParam String subject, @RequestParam String title, @RequestParam String content) { Courseware courseware = contentService.createCourseContent(subject, title, content); return ResponseEntity.ok(courseware); } // 更新课程内容 @PutMapping("/{id}") public ResponseEntity<Courseware> updateCourseContent( @PathVariable Long id, @RequestParam String content) { Courseware updated = contentService.updateCourseContent(id, content); return ResponseEntity.ok(updated); } // 获取所有课程内容 @GetMapping public ResponseEntity<List<Courseware>> getAllCourseContents() { return ResponseEntity.ok(contentService.getAllCourseContents()); } // 导入课件 @PostMapping("/import") public ResponseEntity<String> importCourseware( @RequestParam("file") MultipartFile file, @RequestParam String subject) { contentService.importCourseware(file, subject); return ResponseEntity.ok("课件导入成功"); } } ``` #### 3. CourseController.java - 课程管理控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.dto.TeachingPlanDto; import com.example.teacherassistant.service.ContentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/api/courses") public class CourseController { private final ContentService contentService; @Autowired public CourseController(ContentService contentService) { this.contentService = contentService; } // 创建课程计划 @PostMapping("/plan") public ResponseEntity<TeachingPlanDto> createTeachingPlan(@RequestBody TeachingPlanDto planDto) { TeachingPlanDto created = contentService.createTeachingPlan(planDto); return ResponseEntity.ok(created); } // 更新课程计划 @PutMapping("/plan/{id}") public ResponseEntity<TeachingPlanDto> updateTeachingPlan( @PathVariable Long id, @RequestBody TeachingPlanDto planDto) { TeachingPlanDto updated = contentService.updateTeachingPlan(id, planDto); return ResponseEntity.ok(updated); } // 获取课程计划 @GetMapping("/plan/{id}") public ResponseEntity<TeachingPlanDto> getTeachingPlan(@PathVariable Long id) { return ResponseEntity.ok(contentService.getTeachingPlan(id)); } // 获取所有课程计划 @GetMapping("/plans") public ResponseEntity<List<TeachingPlanDto>> getAllTeachingPlans() { return ResponseEntity.ok(contentService.getAllTeachingPlans()); } } ``` #### 4. ExerciseController.java - 练习管理控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.dto.ExerciseGenReq; import com.example.teacherassistant.model.entity.Exercise; import com.example.teacherassistant.service.AssessmentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/api/exercises") public class ExerciseController { private final AssessmentService assessmentService; @Autowired public ExerciseController(AssessmentService assessmentService) { this.assessmentService = assessmentService; } // 生成练习题 @PostMapping("/generate") public ResponseEntity<Exercise> generateExercise(@RequestBody ExerciseGenReq request) { Exercise exercise = assessmentService.generateExercise( request.getCoursewareId(), request.getDifficulty() ); return ResponseEntity.ok(exercise); } // 批量生成练习题 @PostMapping("/batch-generate") public ResponseEntity<List<Exercise>> batchGenerateExercises( @RequestBody ExerciseGenReq request, @RequestParam int count) { List<Exercise> exercises = assessmentService.batchGenerateExercises( request.getCoursewareId(), request.getDifficulty(), count ); return ResponseEntity.ok(exercises); } // 获取所有练习题 @GetMapping public ResponseEntity<List<Exercise>> getAllExercises() { return ResponseEntity.ok(assessmentService.getAllExercises()); } // 更新练习题 @PutMapping("/{id}") public ResponseEntity<Exercise> updateExercise( @PathVariable Long id, @RequestBody Exercise exercise) { Exercise updated = assessmentService.updateExercise(id, exercise); return ResponseEntity.ok(updated); } } ``` #### 5. AnalysisController.java - 学情分析控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.dto.AnalysisResult; import com.example.teacherassistant.model.entity.StudentAnswer; import com.example.teacherassistant.service.AnalysisService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/api/analysis") public class AnalysisController { private final AnalysisService analysisService; @Autowired public AnalysisController(AnalysisService analysisService) { this.analysisService = analysisService; } // 分析学生答案 @PostMapping("/answers") public ResponseEntity<AnalysisResult> analyzeStudentAnswers( @RequestBody List<StudentAnswer> answers) { AnalysisResult result = analysisService.analyzeAnswers(answers); return ResponseEntity.ok(result); } // 获取知识点掌握情况 @GetMapping("/knowledge-points/{courseId}") public ResponseEntity<AnalysisResult> getKnowledgePointMastery( @PathVariable Long courseId) { AnalysisResult result = analysisService.getKnowledgePointMastery(courseId); return ResponseEntity.ok(result); } // 获取高频错误知识点 @GetMapping("/common-errors/{subject}") public ResponseEntity<AnalysisResult> getCommonErrors( @PathVariable String subject, @RequestParam(required = false) String timeRange) { AnalysisResult result = analysisService.getCommonErrors(subject, timeRange); return ResponseEntity.ok(result); } } ``` #### 6. KnowledgeController.java - 知识库管理控制器 ```java package com.example.teacherassistant.controller; import com.example.teacherassistant.model.entity.KnowledgeDoc; import com.example.teacherassistant.service.KnowledgeService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import org.springframework.web.multipart.MultipartFile; import java.util.List; @RestController @RequestMapping("/api/knowledge") public class KnowledgeController { private final KnowledgeService knowledgeService; @Autowired public KnowledgeController(KnowledgeService knowledgeService) { this.knowledgeService = knowledgeService; } // 上传知识库文档 @PostMapping("/upload") public ResponseEntity<String> uploadKnowledgeDocument( @RequestParam("file") MultipartFile file, @RequestParam String subject) { knowledgeService.uploadDocument(file, subject); return ResponseEntity.ok("文档上传成功"); } // 获取所有知识库文档 @GetMapping("/documents") public ResponseEntity<List<KnowledgeDoc>> getAllDocuments() { return ResponseEntity.ok(knowledgeService.getAllDocuments()); } // 更新知识库文档 @PutMapping("/document/{id}") public ResponseEntity<KnowledgeDoc> updateDocument( @PathVariable Long id, @RequestParam String content) { KnowledgeDoc updated = knowledgeService.updateDocument(id, content); return ResponseEntity.ok(updated); } // 重建知识库索引 @PostMapping("/reindex") public ResponseEntity<String> rebuildKnowledgeIndex() { knowledgeService.rebuildKnowledgeIndex(); return ResponseEntity.ok("知识库索引重建开始"); } // 搜索知识库 @GetMapping("/search") public ResponseEntity<List<KnowledgeDoc>> searchKnowledge( @RequestParam String query, @RequestParam(required = false) String subject) { return ResponseEntity.ok(knowledgeService.searchKnowledge(query, subject)); } } ``` ### 代码说明 1. **RESTful 设计原则**： - 使用标准HTTP方法：GET（查询）、POST（创建）、PUT（更新） - 资源路径命名规范（复数形式） - 参数传递方式：路径参数、查询参数、请求体 2. **请求处理流程**： ```mermaid graph TD A[客户端请求] --> B[Controller接收] B --> C[调用Service层] C --> D[业务处理] D --> E[访问Repository/DB] E --> F[返回响应] ``` 3. **关键功能实现**： - 课程内容管理：创建、更新、导入课件 - 教学计划管理：创建、更新课程计划 - 练习生成：单题/批量生成、难度控制 - 学情分析：答案分析、知识点掌握度、错误统计 - 知识库管理：文档上传、索引重建、知识搜索 4. **异常处理**： - 使用Spring的全局异常处理（未在代码中展示） - 服务层处理业务异常 - 控制器返回标准HTTP状态码 5. **安全考虑**： - 后续需添加@PreAuthorize权限控制 - 敏感操作需要身份验证 - 文件上传需进行类型和大小校验

### 问题分析与解决方案 #### JSON Parse Error (`Unexpected character`) 当服务器接收到无法解析的 JSON 数据时，通常会触发 `JsonParseException`。这种错误可能是由于以下几个原因引起的： 1. **JSON 格式不正确** 输入的 JSON 可能缺少双引号、逗号或其他必要分隔符，导致 Jackson 解析器无法识别其结构[^1]。 2. **特殊字符干扰** 不可见字符（如 `\u00A0` 或 BOM 字节顺序标记）可能导致解析失败[^3]。 3. **请求体为空或损坏** 客户端未提供完整的 JSON 请求体，或者传输过程中数据丢失[^5]。 针对以上情况，建议采取以下措施： - **验证 JSON 合法性** 在接收数据之前，先对其进行合法性检查。例如，在 Java 中可以使用以下代码片段： ```java import com.fasterxml.jackson.databind.ObjectMapper; public class JsonValidator { public static boolean isValidJson(String jsonStr) { ObjectMapper mapper = new ObjectMapper(); try { mapper.readTree(jsonStr); return true; } catch (Exception e) { System.err.println("Invalid JSON format detected."); return false; } } } ``` - **清理隐藏字符** 确保输入数据不含任何非打印字符。可以通过正则表达式去除多余空白字符： ```java String cleanInput = rawInput.replaceAll("[^\\x20-\\x7E]", ""); ``` - **增强容错能力** 修改服务端配置以忽略未知字段或处理部分无效数据： ```properties spring.jackson.deserialization.fail-on-unknown-properties=false ``` --- #### Null Pointer Exception （NPE） 当尝试访问或调用一个为 `null` 的对象上的方法时，会出现 NPE。这通常是由于以下原因之一造成的： 1. **未初始化的对象** 某些变量在声明后未被赋值即直接使用[^6]。 2. **条件判断不足** 缺乏对可能为 `null` 的对象进行充分的安全检查[^8]。 为了避免这类问题的发生，推荐采用以下策略： - **显式判空** 在执行敏感操作前加入额外防护逻辑： ```java if (object != null && object.getMethod() != null) { // Safe to proceed with method invocation. } ``` - **引入 Optional 类型** 利用 Java 8 提供的 `Optional<T>` 来封装可能存在缺失值的情况，减少直接接触裸指针的风险： ```java Optional.ofNullable(object).ifPresent(obj -> obj.performAction()); ``` - **默认值替代机制** 设置合理的默认实例以防备极端状况下的崩溃风险： ```java Object safeObject = (originalObject == null ? new DefaultImplementation() : originalObject); ``` --- ### 综合案例演示 假设我们有一个基于 Spring Boot 构建的知识库管理系统接口 `/api/knowledge-base`，其中涉及到了上述两类常见错误场景。下面是优化后的控制器实现版本： ```java @RestController @RequestMapping("/api/knowledge-base") public class KnowledgeBaseController { @PostMapping(consumes = MediaType.APPLICATION_JSON_VALUE) public ResponseEntity<?> createOrUpdate(@RequestBody(required = false) TbCdcewKnowledgeBase kbEntry) { if (kbEntry == null || !isValid(kbEntry)) { return ResponseEntity.badRequest().body("Invalid or missing knowledge base entry data."); } try { service.saveOrUpdate(kbEntry); return ResponseEntity.ok("Successfully processed the request."); } catch (NullPointerException npe) { log.error("Null pointer encountered during processing.", npe); return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Internal server error occurred due to unexpected state."); } } private boolean isValid(TbCdcewKnowledgeBase entry) { return entry.getId() != null && StringUtils.hasText(entry.getName()) && CollectionUtils.isNotEmpty(entry.getTags()); } } ``` 在此例子中，不仅实现了基本的功能需求，还加入了全面的防御性编程技巧来应对潜在隐患。 --- ###