将posts转为一个module；先建个nest generate module posts，然后把posts整个放到modules里面去，把controller和provider收紧到posts module里面去

src/app.module.ts

@@ -1,12 +1,11 @@
 import { Module } from '@nestjs/common';
 import { AppController } from './app.controller';
 import { AppService } from './app.service';
-import { PostsController } from './posts/posts.controller';
-import { DemoService } from './posts/providers/demo/demo.service';
+import { PostsModule } from './modules/posts/posts.module';
 
 @Module({
-  imports: [],
-  controllers: [AppController, PostsController],
-  providers: [AppService, DemoService],
+  imports: [PostsModule],
+  controllers: [AppController],
+  providers: [AppService],
 })
 export class AppModule {}

src/modules/posts/posts.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { PostsController } from './posts.controller';
+import { DemoService } from "./providers/demo/demo.service";
+
+@Module({
+    controllers: [PostsController],
+    providers: [DemoService]
+})
+export class PostsModule {}

src/modules/posts/providers/demo/demo.service.ts

@@ -1,5 +1,5 @@
 import { Injectable } from '@nestjs/common';
-import { Post } from 'src/posts/interfaces/post.interface';
+import { Post } from 'src/modules/posts/interfaces/post.interface';
 
 @Injectable()
 export class DemoService {