关于node.js：阻止跨源请求：同源策略禁止读取远程… CORS头“Access-Control-Allow-Origin”丢失

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote …CORS header ‘Access-Control-Allow-Origin’ missing

本问题已经有最佳答案，请猛点这里访问。

我有http：// localhost：3000 / edata中的数据

1	[{"_id":"598705ac8f79380367e0a7f2","name":"prasad","age":"28","gender":"male","phone":8790440944},{"_id":"598733508f79380367e0a7f8","name":"ravi","age":"27","gender":"male","phone":"9912881777"}

我想在运行我的客户端应用程序时得到这些数据，即http：// localhost：4200

app.module.ts

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import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import {HttpModule} from"@angular/http";
import { AppComponent } from './app.component';
import {TasksComponent} from"../tasks/tasks.component";
import {TaskServices} from"./services/task.services";

@NgModule({
declarations: [AppComponent, TasksComponent],
imports: [BrowserModule,HttpModule],
providers: [TaskServices],
bootstrap: [AppComponent,TasksComponent]
})
export class AppModule { }

tasks.component.ts

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import {Component, enableProdMode} from '@angular/core';
import {TaskServices} from"../app/services/task.services";
enableProdMode();
@Component({
selector: 'tasks',
templateUrl: './tasks.component.html',
styleUrls: ['./tasks.component.css']
})
export class TasksComponent {
constructor(private taskServices:TaskServices){
this.taskServices.getTasks()
.subscribe(tasks =>{
console.log(tasks);
});
}
title = 'app';
}

task.services.ts

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import {Injectable} from '@angular/core';
import {Http, Headers} from"@angular/http";
import 'rxjs/add/operator/map';

@Injectable()
export class TaskServices{
constructor(private http:Http){
console.log('Task service initialized....');
}
getTasks(){
return this.http.get('http://localhost:3000/edata')
.map(res => res.json());
}

当我运行应用程序时，在控制台中我收到错误跨源请求被阻止：同源策略不允许在http：// localhost：3000 / edata读取远程资源。 (原因：缺少CORS标题'Access-Control-Allow-Origin')。

如何修复错误。以及如何从其他主机获取数据... plz帮助我。