如何正确地从http.request()中捕获异常？
如何正确地从http.request()中捕获异常？
提问于 2016-02-11 05:52:34
我的代码的部分：
import {Injectable} from 'angular2/core';
import {Http, Headers, Request, Response} from 'angular2/http';
import {Observable} from 'rxjs/Observable';
import 'rxjs/add/operator/map';
@Injectable()
export class myClass {
constructor(protected http: Http) {}
public myMethod() {
let request = new Request({
method: "GET",
url: "http://my_url"
});
return this.http.request(request)
.map(res => res.json())
.catch(this.handleError); // Trouble line.
// Without this line code works perfectly.
}
public handleError(error: Response) {
console.error(error);
return Observable.throw(error.json().error || 'Server error');
}
}myMethod()在浏览器控制台产生异常：
原始异常: TypeError: this.http.request(...).map(...).catch不是函数
回答 4
Stack Overflow用户
回答已采纳
发布于 2016-02-11 06:11:55
也许您可以尝试在导入中添加以下内容：
import 'rxjs/add/operator/catch';您还可以执行以下操作：
return this.http.request(request)
.map(res => res.json())
.subscribe(
data => console.log(data),
err => console.log(err),
() => console.log('yay')
);每条评论：
异常: TypeError: Observable_1.Observable.throw不是函数
类似地，您可以使用：
import 'rxjs/add/observable/throw';Stack Overflow用户
发布于 2019-02-04 23:40:41
有几种方法可以做到这一点。两者都非常简单。每一个例子都运行得很好。您可以将其复制到您的项目中并对其进行测试。
第一种方法更可取，第二种方法有点过时，但到目前为止它也是有效的。
1)解决方案1
// File - app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule } from '@angular/common/http';
import { AppComponent } from './app.component';
import { ProductService } from './product.service';
import { ProductModule } from './product.module';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpClientModule
],
providers: [ProductService, ProductModule],
bootstrap: [AppComponent]
})
export class AppModule { }
// File - product.service.ts
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
// Importing rxjs
import 'rxjs/Rx';
import { Observable } from 'rxjs/Rx';
import { catchError, tap } from 'rxjs/operators'; // Important! Be sure to connect operators
// There may be your any object. For example, we will have a product object
import { ProductModule } from './product.module';
@Injectable()
export class ProductService{
// Initialize the properties.
constructor(private http: HttpClient, private product: ProductModule){}
// If there are no errors, then the object will be returned with the product data.
// And if there are errors, we will get into catchError and catch them.
getProducts(): Observable<ProductModule[]>{
const url = 'YOUR URL HERE';
return this.http.get<ProductModule[]>(url).pipe(
tap((data: any) => {
console.log(data);
}),
catchError((err) => {
throw 'Error in source. Details: ' + err; // Use console.log(err) for detail
})
);
}
}2)解决方案2.这是一种老方法，但仍然有效。
// File - app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpModule } from '@angular/http';
import { AppComponent } from './app.component';
import { ProductService } from './product.service';
import { ProductModule } from './product.module';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpModule
],
providers: [ProductService, ProductModule],
bootstrap: [AppComponent]
})
export class AppModule { }
// File - product.service.ts
import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
// Importing rxjs
import 'rxjs/Rx';
import { Observable } from 'rxjs/Rx';
@Injectable()
export class ProductService{
// Initialize the properties.
constructor(private http: Http){}
// If there are no errors, then the object will be returned with the product data.
// And if there are errors, we will to into catch section and catch error.
getProducts(){
const url = '';
return this.http.get(url).map(
(response: Response) => {
const data = response.json();
console.log(data);
return data;
}
).catch(
(error: Response) => {
console.log(error);
return Observable.throw(error);
}
);
}
}Stack Overflow用户
发布于 2016-02-11 06:20:28
需要专门导入RxJS函数。一种简单的方法是使用import * as Rx from "rxjs/Rx"导入其所有要素
然后确保以Rx.Observable的身份访问Observable类。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/35326689
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