创建一个异常过滤器，用来处理异常信息逻辑，nest generate filter demo core/filters

src/core/filters/demo.filter.spec.ts

@@ -0,0 +1,7 @@
+import { DemoFilter } from './demo.filter';
+
+describe('DemoFilter', () => {
+  it('should be defined', () => {
+    expect(new DemoFilter()).toBeDefined();
+  });
+});

src/core/filters/demo.filter.ts

@@ -0,0 +1,6 @@
+import { ArgumentsHost, Catch, ExceptionFilter } from '@nestjs/common';
+
+@Catch()
+export class DemoFilter<T> implements ExceptionFilter {
+  catch(exception: T, host: ArgumentsHost) {}
+}