BLL课件版

BLL课件版.py

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+import json
+from datetime import date
+from typing import List, Optional
+
+from BELL import Student
+
+
+class StudentService:
+    def __init__(self, dal):
+        self.dal = dal
+
+    def add_student(self, student: 'Student') -> bool:
+        if self.dal.check_student_exists(student.sid):
+            raise ValueError(f"学生 ID {student.sid} 已存在")
+
+        validation_errors = student.get_errors()
+        if validation_errors:
+            raise ValueError(f"学生数据校验不通过: {validation_errors}")
+
+        return self.dal.add_student(student)
+
+    def delete_student(self, sid: str) -> bool:
+        if not self.dal.check_student_exists(sid):
+            raise ValueError(f"学生 ID {sid} 不存在")
+
+        return self.dal.delete_student(sid)
+
+    def update_student(self, sid: str, student: 'Student') -> bool:
+        if not self.dal.check_student_exists(sid):
+            raise ValueError(f"学生 ID {sid} 不存在")
+
+        validation_errors = student.get_errors()
+        if validation_errors:
+            raise ValueError(f"学生数据校验不通过: {validation_errors}")
+
+        return self.dal.update_student(sid, student)
+
+    def update_student_partial(self, sid: str, name: Optional[str] = None, height: Optional[int] = None,
+                               birth_date: Optional[date] = None, enrollment_date: Optional[date] = None,
+                               class_name: Optional[str] = None) -> bool:
+        if not self.dal.check_student_exists(sid):
+            raise ValueError(f"学生 ID {sid} 不存在")
+
+        return self.dal.update_student_partial(sid, name, height, birth_date,
+                                               enrollment_date, class_name)
+
+    def get_student_by_id(self, sid: str) -> Optional['Student']:
+        return self.dal.find_student_by_sid(sid)
+
+    def get_students_by_name(self, name: str) -> List['Student']:
+        return self.dal.find_students_by_name(name)
+
+    def get_students_by_class(self, class_name: str) -> List['Student']:
+        return self.dal.find_students_by_class_name(class_name)
+
+    def get_all_students(self) -> List['Student']:
+        return self.dal.get_all_students()
+
+    def get_student_count(self) -> int:
+        return self.dal.get_student_count()
+
+    def get_students_by_height(self, min_height: int, max_height: int) -> List['Student']:
+        if min_height > max_height:
+            raise ValueError("最小身高不能大于最大身高")
+
+        return self.dal.find_students_by_height_range(min_height, max_height)
+
+    def get_avg_height(self) -> float:
+        total_height = self.dal.get_total_height()
+        student_count = self.dal.get_student_count()
+
+        return total_height / student_count if student_count > 0 else 0.0
+
+    def get_students_by_enrollment_year(self, year: int) -> List['Student']:
+        return self.dal.find_students_by_enrollment_year(year)
+
+    def get_students_by_age(self, min_age: int, max_age: int) -> List['Student']:
+        if min_age > max_age:
+            raise ValueError("最小年龄不能大于最大年龄")
+
+        today = date.today()
+        min_birth_date = date(today.year - max_age - 1, today.month, today.day)
+        max_birth_date = date(today.year - min_age, today.month, today.day)
+
+        return self.dal.find_students_by_birth_date_range(min_birth_date, max_birth_date)
+
+    def export_students(self, file_path: str) -> bool:
+        try:
+            students = self.get_all_students()
+            with open(file_path, 'w', encoding='utf-8') as f:
+                json.dump([student.to_dict() for student in students], f, ensure_ascii=False, indent=4)
+            return True
+        except Exception as e:
+            raise RuntimeError(f"导出学生数据失败: {str(e)}") from e
+
+    def import_students(self, file_path: str) -> int:
+        try:
+            with open(file_path, 'r', encoding='utf-8') as f:
+                student_dicts = json.load(f)
+
+            added_count = 0
+            for student_dict in student_dicts:
+                student = Student.from_dict(student_dict)
+
+                if not student.is_valid:
+                    raise ValueError(f"学生数据校验不通过: {student.get_errors()}")
+
+                if self.dal.check_student_exists(student.sid):
+                    continue
+
+                self.dal.add_student(student)
+                added_count += 1
+
+            return added_count
+        except Exception as e:
+            raise RuntimeError(f"导入学生数据失败: {str(e)}") from e
+
+    def clear_all_students(self) -> None:
+        self.dal.clear_all_students()