Angular4.x跨域请求

Angular4.x请求

码云地址:

https://gitee.com/ccsoftlucifer/Angular4Study

1. 搭建工程

新建一个工程angulardemo03

ng new angulardemo03

npm install 更新依赖

2. 新建组件

在app目录新建文件夹components,自己自定义的所有的组件都放在这个目录下面.

ng g component components/news

目录结构如下:

3.添加请求相关的model

编辑app.modle.ts

import { HttpClientModule  } from '@angular/common/http'; 

@NgModule({
  declarations: [
    AppComponent,
    NewsComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

4.编写代码

news.component.html 编写一个按钮用来发送请求:

<h2>你好angular</h2>
<p>
  news works!
</p>

<br>
<button (click)="requestData()">请求数据</button>
从服务器拿到的值:
{{value}}

news.component.ts编写逻辑,导入http服务

import { Component, OnInit } from '@angular/core';

import {HttpClient} from '@angular/common/http';
@Component({
  selector: 'app-news',
  templateUrl: './news.component.html',
  styleUrls: ['./news.component.css']
})
export class NewsComponent implements OnInit {
  public value:any
  constructor(private http:HttpClient) { }

  ngOnInit() {
    // this.http.get('http://localhost:8080/user/findUser?id=1')
    //  .subscribe(res=>{ this.value = res })

  }
  //请求数据方法
  requestData(){
    console.log('请求数据');
    var url='http://localhost:8080/user/findUser?id=1';//这里定义一个地址,要允许跨域
    this.http.get(url).subscribe(function(data){
      console.log(data);
    },function(err){
      console.log(err);
    })
  }

}

5.解决跨域

　　由于前端工程是localhost:4200,请求后端工程Localhost:8080,会出现跨域错误:

　　Access-Control-Allow-Origin' header is present on the requested resource.

　　解决办法:

　　5.1 在项目的根目录添加proxy.config.json文件

　　

{
    "/": {
        "target": "http://localhost:8080/"
    }
}

　　5.2修改package.json文件

"scripts": {
    "ng": "ng",
    "start": "ng serve --proxy-config proxy.config.json",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },

　　5.3修改angular.json

"serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "angulardemo03:build",
            "proxyConfig":"proxy.config.json"
          },
          "configurations": {
            "production": {
              "browserTarget": "angulardemo03:build:production"
            }
          }
        },

　　5.4服务器端添加注解

 @CrossOrigin(origins = "http://localhost:4200",allowCredentials = "true")

　　

这样数据就拿过来了啦~

　　使用RxJS进行请求发送:

import { Observable, Subject, asapScheduler, pipe, of, from, interval, merge, fromEvent,  SubscriptionLike, PartialObserver, concat } from 'rxjs';
import { map, filter, scan } from 'rxjs/operators';
import { webSocket } from 'rxjs/webSocket';
import { ajax } from 'rxjs/ajax';
import { TestScheduler } from 'rxjs/testing';

　　请求:

//另外一种请求方式
    useRxJsRequestData(){
      var _result=this;
      console.log('请求数据');
      if(this.inputValue==''){
          //用户没有输入
          alert('请先输入值');
      }else{
          //用户有输入的值
          var url='http://localhost:8080/user/findUser?id='+this.inputValue;
          this.http.get(url).subscribe(res =>{
            console.log(res);
            console.log(typeof(res));
            console.log(res['id']);
            var _this = this;
            
           _this.obj.id=res['id'];
            _this.obj.useName=res['userName'];
            _this.obj.password=res['password'];
            _this.obj.age=res['age'];
          })
         //console.log(map);
      }
    }