Angular 2 Spring Boot 服务器端事件 [英] Angular 2 spring boot server side events

问题描述

有人可以为我提供 Spring Boot 服务器端事件的示例吗?

Can somebody please provide me an example for spring boot server side events?

基本上我需要将服务器端事件推送到浏览器.我正在使用 angular 2 和 Spring Boot 后端.请提供 1 个示例示例，我找不到好的示例.

Basically I need to push server side events to browser. I'm using angular 2 and spring boot backend. Please provide me 1 sample example, I'm unable to find good examples.

@Controller
public class SSEController {

    private final List<SseEmitter> emitters = new ArrayList<>();

    @RequestMapping(path = "/stream", method = RequestMethod.GET)
    public SseEmitter stream() throws IOException {

        SseEmitter emitter = new SseEmitter();

        emitters.add(emitter);
        emitter.onCompletion(() -> emitters.remove(emitter));

        return emitter;
    }
}

如何在 Angular 2 中从服务器持续推送数据以及如何订阅此事件?

How to push data continuously from server and how to subscribe to this event in Angular 2?

推荐答案

有一个 Spring Rest 控制器

Have a Spring Rest controller

SseController.java

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

@RestController
public class SSEController {

    public static final List<SseEmitter> emitters = Collections.synchronizedList( new ArrayList<>());

    @RequestMapping(path = "/stream", method = RequestMethod.GET)
    public SseEmitter stream() throws IOException {

        SseEmitter emitter = new SseEmitter();

        emitters.add(emitter);
        emitter.onCompletion(() -> emitters.remove(emitter));

        return emitter;
    }
}

ServiceClass.java

public void sendSseEventsToUI(Notification notification) { //your model class
        List<SseEmitter> sseEmitterListToRemove = new ArrayList<>();
        SSEController.emitters.forEach((SseEmitter emitter) -> {
            try {
                emitter.send(notification, MediaType.APPLICATION_JSON);
            } catch (IOException e) {
                emitter.complete();
                sseEmitterListToRemove.add(emitter);
                e.printStackTrace();
            }
        });
        SSEController.emitters.removeAll(sseEmitterListToRemove);
    }

最后在 Angular2 组件中做这个

finally in Angular2 component do this

notification.component.ts

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

declare let EventSource:any;

@Component({
    selector: 'notification-cmp',
    templateUrl: 'notification.component.html'  
})

export class NotificationComponent implements OnInit {
   connect(): void {
        let source = new EventSource('http://localhost:8080/stream');
        source.addEventListener('message', message => {
            let n: Notification; //need to have this Notification model class in angular2
            n = JSON.parse(message.data);
            console.log(message.data); 
        });
    }
}

这篇关于Angular 2 Spring Boot 服务器端事件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！