angular HttpClient get 方法获取数据

请先查看 上一篇文章HttpClient 配置，之后在进行。

使用

this.myhttp.get('http://192.168.2.139:9002/api/patients')方法，读取webapi。因为get方法是通过AJAX方法读取数据的，所以服务器要可以跨域访问， 具体方法查询webapi文章

  1  import { Component, OnInit } from '@angular/core' ;
   2  import { HttpClient } from '@angular/common/http' ;
   3  import { Patient } from './app.patient.server' ;
   4   @Component({
   5    selector: 'app-root' ,
   6    templateUrl: './app.component.html' ,
   7    styleUrls: ['./app.component.css' ]
   8   })
   9  
 10   export class AppComponent implements OnInit {
  11    title = 'angular4.3' ;
  12     results: string[];
  13    myPatientList: Patient[] =  [];
  14  
 15   16     constructor(
  17       private myhttp: HttpClient
  18     ) { }
  19  
 20    ngOnInit():  void   {
  21       this .myhttp.get('http://192.168.2.139:9002/api/patients' )
  22        .subscribe(data =>  {
  23           this .myPatientList = (<any>data).map(u =>  new   Patient({
  24             id: u.PatientId,
  25             FirstName: u.Details.FirstName,
  26             LastName: u.Details.LastName,
  27             MiddleName: u.Details.MiddleName,
  28             BirthDate: u.Details.BirthDate,
  29             Gender: u.Details.Gender,
  30             PhoneNumber: u.PersonalInfo.PhoneNumberPrimary,
  31             ZIPCODE: u.PersonalInfo.ZIPCODE,
  32             City: u.PersonalInfo.City,
  33             Street: u.PersonalInfo.Street,
  34             EmailAddress: u.PersonalInfo.EmailAddressPrimary,
  35             CitizenServiceNumber: u.PersonalInfo.ServiceNumber
  36           }));
  37           38         });
  39     }
  40  }

(<any>data).map()方法直接把读取data数据转换成实体类。
 【注：需要查看自己的json文件，对应好结构】  网上很多json都是以results[]开头。以所用(<any>data).results.map() 这个问题真的卡了我很久，在同事长庆的帮助下才得以解决。

实体类代码，如下：

  1   export class Patient {
   2       id: string;
   3       FirstName: string;
   4       LastName: string;
   5       MiddleName: string;
   6       BirthDate: string;
   7       Gender: string;
   8       PhoneNumber: string;
   9       ZIPCODE: string;
  10       City: string;
  11       Street: string;
  12       EmailAddress: string;
  13       CitizenServiceNumber: string;
  14  
 15       public constructor(
  16        fields? : {
  17           id: string,
  18           FirstName: string,
  19           LastName: string,
  20           MiddleName: string,
  21           BirthDate: string,
  22           Gender: string,
  23           PhoneNumber: string,
  24           ZIPCODE: string,
  25           City: string,
  26           Street: string,
  27           EmailAddress: string,
  28           CitizenServiceNumber: string
  29         }) {
  30         //   tslint:disable-next-line:curly 
 31         if  (fields) Object.assign( this  , fields);
  32       }
  33  
 34       getFullName(): string {
  35         return   this .FirstName + ' ' +  this  .LastName;
  36       }
  37    }

前台调用很简单，直接读取实体类就可以了

  1   <  div   style  ="text-align:center"  > 
  2     <  h1  > 
  3       Welcome to {{title}}!
   4     </  h1  > 
  5     {{results}}
   6     <  h2  > ngfor </  h2  > 
  7     <  ul  > 
  8         <  li   *ngFor  ="let myPatient of myPatientList"   > 
  9             id:{{myPatient.id}} FirstName :{{myPatient.FirstName}}
  10         </  li  > 
 11   </  ul  > 
 12   </  div  > 

显示如下图：

注：这个用法写的还很简单，还需要传参数，加头文件之类的方法，不过已经可以基本的读取数据了。

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