NestJS服务抛出异常导致服务崩溃的问题求助

想在NestJS的Service中抛出异常，在Controller中处理后向前端返回JSON格式的错误信息，但实际触发异常时，NestJS服务器直接崩溃，而非返回预期的404响应。

GeneratorController #

@ApiTags('Generator')
@Controller({
  path: 'api/generator',
  version: '1',
})
export class GeneratorController {
  private readonly logger = new Logger(GeneratorController.name);
  constructor(private tractionUnitService: TractionUnitGeneratorService) {}
  
  @Get('batch/preview')
  @ApiResponse({
    status: 200,
    description: 'Sucessfuly get batch preview',
  })
  @ApiResponse({
    status: 404,
    description: 'Error your batch number is not found',
  })
  async batchPreview(@Query('batchNumber') batchNumber: number): Promise<GenerationBatch> {
    try{
      return batch = this.tractionUnitService.getBatch(batchNumber);
    }catch(e){
      this.logger.error(e)
      throw e;
    }
  } 
}

TractionUnitGeneratorService #

@Injectable()
export class TractionUnitGeneratorService {

  public async getBatch(batchNumber: number): Promise<GenerationBatch> {
    const batchs = (await this.getBatchs()).value.filter((bat) => bat.batchNumber == batchNumber);
    if (batchs.length == 1) {
      return batchs[0];
    } else {
      throw new NotFoundException(`Batch n°${batchNumber} not found`);
    }
 }
}

C:\Users\mrsolarius\Documents\Projets\****\back\src\generator\traction-unit-generator\traction-unit-generator.service.ts:75
      throw new NotFoundException({
            ^
NotFoundException: Batch n°1 not found
    at TractionUnitGeneratorService.getBatch (C:\Users\mrsolarius\Documents\Projets\****\back\src\generator\traction-unit-generator\traction-unit-generator.service.ts:75:13)
    at GeneratorControlerController.batchPreview (C:\Users\mrsolarius\Documents\Projets\****\back\src\controllers\generator\generator.controller.ts:105:32)
    at C:\Users\mrsolarius\Documents\Projets\****\back\node_modules\@nestjs\core\router\router-execution-context.js:38:29
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at C:\Users\mrsolarius\Documents\Projets\****\back\node_modules\@nestjs\core\router\router-execution-context.js:46:28
    at C:\Users\mrsolarius\Documents\Projets\****\back\node_modules\@nestjs\core\router\router-proxy.js:9:17

[System Information]
OS Version     : Windows 10
NodeJS Version : v16.15.0
NPM Version    : 8.5.5 

[Nest CLI]
Nest CLI Version : 9.0.0

[Nest Platform Information]
platform-express version : 9.0.1
schematics version       : 9.0.1
swagger version          : 6.0.1
testing version          : 9.0.1
common version           : 9.0.1
axios version            : 0.1.0
core version             : 9.0.1
cli version              : 9.0.0

服务器崩溃的核心原因是异步方法未使用await调用，导致try/catch无法捕获Service抛出的异步异常，最终异常冒泡到Nest的顶层未被处理。具体修复点：

• 添加await调用异步方法：
  Service的getBatch是异步方法，Controller中调用时必须加await，否则返回的是Promise对象，且异步异常无法被当前try/catch捕获。

• 修复变量声明问题：
  原代码中return batch = ...的写法存在未声明变量的问题，应直接返回await后的结果，或先声明变量再赋值。

修复后的Controller代码：

@ApiTags('Generator')
@Controller({
  path: 'api/generator',
  version: '1',
})
export class GeneratorController {
  private readonly logger = new Logger(GeneratorController.name);
  constructor(private tractionUnitService: TractionUnitGeneratorService) {}
  
  @Get('batch/preview')
  @ApiResponse({
    status: 200,
    description: 'Sucessfuly get batch preview',
  })
  @ApiResponse({
    status: 404,
    description: 'Error your batch number is not found',
  })
  async batchPreview(@Query('batchNumber') batchNumber: number): Promise<GenerationBatch> {
    try{
      // 添加await，并修复变量问题
      return await this.tractionUnitService.getBatch(batchNumber);
    }catch(e){
      this.logger.error(e)
      throw e;
    }
  } 
}

额外说明：NestJS自带的全局异常过滤器会自动处理所有继承自HttpException的异常（包括NotFoundException），即使去掉Controller中的try/catch，只要正确await异步方法，框架会自动返回对应的JSON错误响应（包含状态码和错误信息）。如果仅需要日志记录，保留try/catch并重新抛出异常即可。

内容的提问来源于stack exchange，提问作者MrSolarius