要在Angular 8中阻止页面刷新后路由重置，可以使用浏览器的LocalStorage或SessionStorage保存当前路由状态，并在页面加载时恢复该状态。

下面是一个示例代码，演示如何在页面刷新后阻止路由重置：

1. 创建一个名为RouteStateService的服务，用于保存和恢复路由状态：

import { Injectable } from '@angular/core';
import { Router, NavigationEnd } from '@angular/router';

@Injectable({
  providedIn: 'root'
})
export class RouteStateService {
  private routeStateKey = 'routeState';

  constructor(private router: Router) { }

  public saveRouteState(): void {
    const state = this.router.routerState.snapshot;
    localStorage.setItem(this.routeStateKey, JSON.stringify(state));
  }

  public restoreRouteState(): void {
    const savedState = localStorage.getItem(this.routeStateKey);
    if (savedState) {
      const state = JSON.parse(savedState);
      this.router.navigateByUrl(state.url);
    }
  }

  public clearRouteState(): void {
    localStorage.removeItem(this.routeStateKey);
  }
}

2. 在app.component.ts中使用RouteStateService：

import { Component, OnInit } from '@angular/core';
import { RouteStateService } from './route-state.service';

@Component({
  selector: 'app-root',
  template: `
    
  `
})
export class AppComponent implements OnInit {
  constructor(private routeStateService: RouteStateService) { }

  ngOnInit(): void {
    this.routeStateService.restoreRouteState();

    // 监听路由变化，并在路由变化时保存状态
    this.router.events.subscribe(event => {
      if (event instanceof NavigationEnd) {
        this.routeStateService.saveRouteState();
      }
    });
  }
}

3. 在每个需要阻止路由重置的组件中使用RouteStateService：

import { Component } from '@angular/core';
import { RouteStateService } from './route-state.service';

@Component({
  selector: 'app-example',
  template: `
    
  `
})
export class ExampleComponent {
  constructor(private routeStateService: RouteStateService) { }

  ngOnDestroy(): void {
    this.routeStateService.clearRouteState();
  }
}

通过以上代码，当用户刷新页面时，路由状态会被保存并恢复，从而阻止路由重置。请根据实际需求在需要阻止路由重置的组件中调用clearRouteState()方法，以清除路由状态。