在 Angular 应用程序中使用 MVC 后端时，由于 URL 解析不正确，可能会出现返回 404 的情况。这可能是由于应用程序的路由设置或后端路由设置不正确。

解决此问题的方法是检查 URL 解析设置并确保它正确。还可以尝试使用 HttpInterceptors 进行拦截，并在请求中添加正确的 URL，如下所示：

1. 创建 HttpInterceptor

import { Injectable } from '@angular/core'; import { HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';

@Injectable() export class APIInterceptor implements HttpInterceptor { intercept(req: HttpRequest, next: HttpHandler) { const apiReq = req.clone({ url: http://localhost:5000/api/${req.url} }); return next.handle(apiReq); } }

2. 将 HttpInterceptor 注册到 AppModule

import { NgModule } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http'; import { AppComponent } from './app.component'; import { APIInterceptor } from './api.interceptor';

@NgModule({ declarations: [AppComponent], imports: [BrowserModule, HttpClientModule], providers: [{ provide: HTTP_INTERCEPTORS, useClass: APIInterceptor, multi: true }], bootstrap: [AppComponent] }) export class AppModule { }

3. 测试 API 调用

import { Component, OnInit } from '@angular/core'; import { HttpClient } from '@angular/common/http';

@Component({ selector: 'app-root', template: Test API

constructor(private http: HttpClient) {}

ngOnInit() {}

testAPI() { this.http.get('products').subscribe(response => { this.response = response; }); } }

这应该可以解决 Angular CLI 使用