小编Vit*_*sky的帖子

当我向服务器发送POST请求时,我收到一个错误:

Failed to load http://localhost:8181/test: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access. The response had HTTP status code 403.

后端是用Java Spring编写的.我创建测试的方法:

createTest() {
    const body = JSON.stringify({
      'description': 'grtogjoritjhio',
      'passingTime': 30,
      'title': 'hoijyhoit'
    });

    const httpOptions = {
      headers: new HttpHeaders({
          'Content-Type': 'application/json',
          'Accept': 'application/json'
        }
      )
    };

    return this._http.post(`${this._config.API_URLS.test}`, body, httpOptions)
      .subscribe(res => {
        console.log(res );
      }, error => {
        console.log(error); …

我只想将firbase安装为数据库，但不断收到此错误：

ERROR Error: permission_denied at /courses: Client doesn't have permission to access the desired data.
    at errorForServerCode (index.cjs.js:647)
    at onComplete (index.cjs.js:9114)
    at Object.onComplete (index.cjs.js:12681)
    at index.cjs.js:11797
    at PersistentConnection.push../node_modules/@firebase/database/dist/index.cjs.js.PersistentConnection.onDataMessage_ (index.cjs.js:12052)
    at Connection.push../node_modules/@firebase/database/dist/index.cjs.js.Connection.onDataMessage_ (index.cjs.js:11337)
    at Connection.push../node_modules/@firebase/database/dist/index.cjs.js.Connection.onPrimaryMessageReceived_ (index.cjs.js:11331)
    at WebSocketConnection.onMessage (index.cjs.js:11232)
    at WebSocketConnection.push../node_modules/@firebase/database/dist/index.cjs.js.WebSocketConnection.appendFrame_ (index.cjs.js:10837)
    at WebSocketConnection.push../node_modules/@firebase/database/dist/index.cjs.js.WebSocketConnection.handleIncomingFrame (index.cjs.js:10887)

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule } from 'angularfire2/database';
import { environment } from '../environments/environment';

  imports: [
    BrowserModule,
    AngularFireModule.initializeApp(environment.firebase),
    AngularFireDatabaseModule, …