NestJS开发核心概念Providers类基本用法详解

// nanjiu.service.ts
import { Injectable } from '@nestjs/common';
import { CreateNanjiuDto } from './dto/create-nanjiu.dto';
import { UpdateNanjiuDto } from './dto/update-nanjiu.dto';
@Injectable()
export class NanjiuService {
  create(createNanjiuDto: CreateNanjiuDto) {
    return 'This action is nanjiu post';
  }
  findAll() {
    return `This action returns all nanjiu`;
  }
  findOne(id: number) {
    return `This action returns a #${id} nanjiu`;
  }
  update(id: number, updateNanjiuDto: UpdateNanjiuDto) {
    return `This action updates a #${id} nanjiu`;
  }
  remove(id: number) {
    return `This action removes a #${id} nanjiu`;
  }
}

// nanjiu.module.ts
@Module({
  controllers: [NanjiuController],
  providers: [NanjiuService]
})
export class NanjiuModule {}

// nanjiu.controller.ts
@Controller('nanjiu')
export class NanjiuController {
  constructor(private readonly nanjiuService: NanjiuService) {}
  @Post()
  @Header('Cache-Control', 'none')
  create(@Body() createNanjiuDto: CreateNanjiuDto) {
    console.log('body', createNanjiuDto)
    return this.nanjiuService.create(createNanjiuDto);
  }
}

// nanjiu.module.ts
@Module({
  controllers: [NanjiuController], // 控制器
  providers: [{
    provide: 'NANJIU',  // 自定义依赖注入的标识
    useClass: NanjiuService // 依赖注入的类
  }]
})
export class NanjiuModule {}

// nanjiu.controller.ts
@Controller('nanjiu')
export class NanjiuController {
  constructor(@Inject('NANJIU') private readonly nanjiuService: NanjiuService) {}

  @Post()
  @Header('Cache-Control', 'none')
  create(@Body() createNanjiuDto: CreateNanjiuDto) {
    console.log('body', createNanjiuDto, this.nanjiuService)
    return true
    return this.nanjiuService.create(createNanjiuDto);
  }
}

// nanjiu.module.ts
@Module({ // 模块装饰器
  controllers: [NanjiuController], // 控制器
  providers: [{
    provide: 'NANJIU',  // 自定义依赖注入的标识
    useValue: {
      name: 'nanjiu' // 依赖注入的值
    }
  }]
})

// nanjiu.module.ts
import { Module } from '@nestjs/common';
import { NanjiuService } from './nanjiu.service';
import { UserService } from 'src/user/user.service';
import { NanjiuController } from './nanjiu.controller';
@Module({ // 模块装饰器
  controllers: [NanjiuController], // 控制器
  providers: [{
    provide: 'NANJIU',  // 自定义依赖注入的标识
    useClass: NanjiuService // 依赖注入的类
  },
  UserService,
  {
    provide: 'USER', // 自定义依赖注入的标识
    useFactory: (...args) => { // 工厂模式
      console.log('useFactory', args)
      return new UserService() // 依赖注入的类
    },
    inject: [UserService] // 依赖注入的类
  }
]
})
export class NanjiuModule {}

import { Injectable, Optional, Inject } from '@nestjs/common';
@Injectable()
export class HttpService<T> {
  constructor(@Optional() @Inject('HTTP_OPTIONS') private httpClient: T) {}
}

// nanjiu.module.ts
@Module({ // 模块装饰器
  controllers: [NanjiuController], // 控制器
  providers: [
  UserService,
  {
    provide: 'USER', // 自定义依赖注入的标识
    useFactory: async () => { // 工厂模式
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          resolve(new UserService())
        }, 1000)
      })
    },
    inject: [UserService] // 依赖注入的类
  }
]
})
export class NanjiuModule {}