在Angular中，HttpErrorInterceptor是用来捕获和处理HTTP请求错误的拦截器。然而，它本身无法直接实现重定向功能。但是，我们可以通过以下方法解决这个问题：

1. 使用Router来实现重定向：可以在HttpErrorInterceptor中注入Router，并在错误处理函数中使用Router来导航到指定的路由。

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent, HttpErrorResponse } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';
import { Router } from '@angular/router';

@Injectable()
export class HttpErrorInterceptor implements HttpInterceptor {
  constructor(private router: Router) {}

  intercept(request: HttpRequest, next: HttpHandler): Observable> {
    return next.handle(request).pipe(
      catchError((error: HttpErrorResponse) => {
        if (error.status === 401) {
          // Redirect to login page
          this.router.navigate(['/login']);
        }
        return throwError(error);
      })
    );
  }
}

2. 使用Location来实现重定向：可以在HttpErrorInterceptor中注入Location，并在错误处理函数中使用Location来进行重定向。

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

@Injectable()
export class HttpErrorInterceptor implements HttpInterceptor {
  constructor(private location: Location) {}

  intercept(request: HttpRequest, next: HttpHandler): Observable> {
    return next.handle(request).pipe(
      catchError((error: HttpErrorResponse) => {
        if (error.status === 401) {
          // Redirect to login page
          this.location.go('/login');
        }
        return throwError(error);
      })
    );
  }
}

请注意，以上示例中的重定向路径（'/login'）仅作为示例，你需要根据你的实际情况进行修改。同时，确保在app.module.ts中将HttpErrorInterceptor添加到providers数组中以进行拦截器的注册。

import { NgModule } from '@angular/core';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { HttpErrorInterceptor } from './http-error.interceptor';

@NgModule({
  imports: [
    HttpClientModule
  ],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: HttpErrorInterceptor,
      multi: true
    }
  ]
})
export class AppModule { }

这样，当HTTP请求返回401错误时，用户将被重定向到指定的路由。