尝试合并，所有代码需要调整from后文件路径。

students/main.py

@@ -1,9 +1,11 @@
-from fastapi import FastAPI
-from students.api.students_api import students_api
+from fastapi import FastAPI,APIRouter
+from students.api.students_api import s_api
 from students.databases import *
 from students.model import students_model
 from contextlib import asynccontextmanager
 
+Students_API = APIRouter()
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     Base.metadata.create_all(engine1)
@@ -12,14 +14,13 @@ async def lifespan(app: FastAPI):
 
 app = FastAPI(title="学生管理系统",lifespan=lifespan) # 这里必须把上面写的加上
 
-app.include_router(students_api,tags=["students"])
-
-
-def main():
-    print("Hello from student-manage-system!")
+app.include_router(s_api,tags=["students"])
 
 
 if __name__ == "__main__":
+    def main():
+        print("Hello from student-manage-system!")
+
     import uvicorn
     uvicorn.run("main:app", host="0.0.0.0", port=51000)