小编Jit*_*uja的帖子

这是我的文件userdata.service.ts:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import {Observable} from 'rxjs';
import { map } from "rxjs/operators";
import { catchError } from 'rxjs/operators';
import { Data } from './userdata';

@Injectable()
export class UserDataService {

  url : "http://localhost:4200/assets/data/userdata.json";
  constructor(private http:Http) { }  

  getDataWithObservable() : Observable<any>{
      return this.http.get(this.url)
            .pipe(
              map(this.extractData),
              catchError(this.handleErrorObservable)
            );
  }

    private extractData(res: Response) 
    {
        let body = res.json();      
        return body;
    }

    private handleErrorObservable (error: Response | any) 
    {   
        return Observable.throw(error.message || error); …

HTML:

<div *ngIf="userdata; else blank;">                         
 <table>
  <thead>
   <tr>
    <th>Id</th>
    <th>Name</th>
    <th>Email</th>
    <th>Address</th>
    <th>Role</th>
    <th>Gender</th>
    <th>Actions</th>
   </tr>
  </thead>
  <tbody>
   <tr *ngFor="let data of userdata">                                          
    <td>{{data.Id}}</td>
    <td>{{data.Name}}</td>
    <td>{{data.Email}}</td>
    <td>{{data.Address}}</td>
    <td>{{data.Role}}</td>
    <td>{{data.Gender}}</td>
    <td>
     <button type="button" (click)="setUser(data)" class="btn btn-default btn-sm edit">
      <span class="glyphicon glyphicon-edit"/> Edit</button>                                              
     <button type="button" id="close" style="height: 30px;"
      (click)="deleteUser(data.Id)" class="btn btn-default btn-sm close" aria-label="Close">
      <span aria-hidden="true">&times;</span>
     </button>
    </td>                                           
   </tr>  
  </tbody>
 </table>
</div>
<ng-template #blank>No Records found...</ng-template>

这是我在userdata数组中得到的:

[{
    "Id": "1",
    "Name": "sdfd",
    "Email": "fdg",
    "Address": "dfg",
    "Role": "Admin",
    "Gender": "male"
}, { …

这是我在book.service.ts中的代码:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import {Observable} from 'rxjs';
import { Book } from './book';
import { map } from "rxjs/operators";
import { catchError } from 'rxjs/operators';

//import { Component, OnInit } from '@angular/core';
//import {HttpClient} from "@angular/common/http";
//import { Observable } from 'rxjs/Observable'; 
//import 'rxjs/add/operator/map';
//import 'rxjs/add/operators/catch';
//import 'rxjs/operators/toPromise';

@Injectable()
export class BookService 
{
    url = "http://localhost:4200/assets/data/books.json";

    constructor(private http:Http) { }

    getBooksWithObservable(): Observable<Book[]> 
    {
        return this.http.get(this.url)
                .pipe(map(this.extractData))
                .catchError(this.handleErrorObservable);
    }
    getBooksWithPromise(): …