在Angular中，可以通过设置HTTP客户端的配置来忽略证书签名。以下是一个示例解决方法：

1. 创建一个新的Angular服务，例如http-client.service.ts。

import { Injectable } from '@angular/core';
import { HttpClient, HttpHandler, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class HttpClientService extends HttpClient {
  constructor(handler: HttpHandler) {
    super(handler);
  }

  request(method?: any, url?: any, options?: any): Observable {
    if (!options) {
      options = {};
    }
    options.withCredentials = true; // 忽略证书签名

    return super.request(method, url, options)
      .pipe(
        catchError((error: HttpErrorResponse) => {
          return throwError(error);
        })
      );
  }
}

2. 在根模块（通常是app.module.ts）中，将HttpClientService添加到providers数组中，以便在整个应用程序中使用它。

import { NgModule } from '@angular/core';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { HttpClientService } from './http-client.service';

@NgModule({
  imports: [
    HttpClientModule
  ],
  providers: [
    {
      provide: HttpClientService,
      useClass: HttpClientService
    }
  ]
})
export class AppModule { }

3. 在需要使用HTTP客户端的地方，使用HttpClientService代替原始的HttpClient。

import { Component } from '@angular/core';
import { HttpClientService } from './http-client.service';

@Component({
  selector: 'app-example',
  template: `
    发起请求
  `
})
export class ExampleComponent {
  constructor(private httpClient: HttpClientService) {}

  makeRequest() {
    this.httpClient.get('https://example.com/api/data')
      .subscribe(
        response => {
          console.log(response);
        },
        error => {
          console.error(error);
        }
      );
  }
}

以上示例中，HttpClientService继承自HttpClient，在每次请求时将options.withCredentials设置为true，以忽略证书签名。