我試圖在使用已編碼的JSON服務器時運行Angular 4應用程序。我遇到的問題是我不明白在端口4200上運行的Angular 4應用程序如何可以在端口3000上同時與JSON服務器通信。該應用程序是一個CRUD的例子,但是當我嘗試添加一些東西時,什麼也不會發布。使用JSON服務器運行Angular 4應用程序
這是我article.service.ts:
@Injectable()
export class ArticleService {
//URL for CRUD operations
articleUrl = "http://localhost:3000/articles";
//Create constructor to get Http instance
constructor(private http:Http) {
}
//Fetch all articles
getAllArticles(): Observable<Article[]> {
return this.http.get(this.articleUrl)
.map(this.extractData)
.catch(this.handleError);
}
//Create article
createArticle(article: Article):Observable<number> {
let cpHeaders = new Headers({ 'Content-Type': 'application/json' });
let options = new RequestOptions({ headers: cpHeaders });
return this.http.post(this.articleUrl, article, options)
.map(success => success.status)
.catch(this.handleError);
}
//Fetch article by id
getArticleById(articleId: string): Observable<Article> {
let cpHeaders = new Headers({ 'Content-Type': 'application/json' });
let options = new RequestOptions({ headers: cpHeaders });
console.log(this.articleUrl +"/"+ articleId);
return this.http.get(this.articleUrl +"/"+ articleId)
.map(this.extractData)
.catch(this.handleError);
}
//Update article
updateArticle(article: Article):Observable<number> {
let cpHeaders = new Headers({ 'Content-Type': 'application/json' });
let options = new RequestOptions({ headers: cpHeaders });
return this.http.put(this.articleUrl +"/"+ article.id, article, options)
.map(success => success.status)
.catch(this.handleError);
}
//Delete article
deleteArticleById(articleId: string): Observable<number> {
let cpHeaders = new Headers({ 'Content-Type': 'application/json' });
let options = new RequestOptions({ headers: cpHeaders });
return this.http.delete(this.articleUrl +"/"+ articleId)
.map(success => success.status)
.catch(this.handleError);
}
private extractData(res: Response) {
let body = res.json();
return body;
}
private handleError (error: Response | any) {
console.error(error.message || error);
return Observable.throw(error.status);
}
}
這是我db.json:
{
"articles": [
{
"id": 1,
"title": "Android AsyncTask Example",
"category": "Android"
}
]
}
請編輯您的問題並在您使用服務的地方添加代碼。 – n00dl3