在Angular中，可以使用RxJS的Subject来实现全局消息服务。下面是一个解决方法的代码示例：

首先，创建一个全局消息服务的文件，例如message.service.ts：

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class MessageService {
  private subject = new Subject();

  sendMessage(message: string) {
    this.subject.next({ text: message });
  }

  clearMessage() {
    this.subject.next();
  }

  getMessage() {
    return this.subject.asObservable();
  }
}

然后，在需要发送消息的组件中，注入MessageService并使用sendMessage方法发送消息：

import { Component } from '@angular/core';
import { MessageService } from './message.service';

@Component({
  selector: 'app-sender',
  template: `
    发送消息
  `
})
export class SenderComponent {
  constructor(private messageService: MessageService) {}

  sendMessage() {
    this.messageService.sendMessage('Hello from sender component!');
  }
}

接着，在需要接收消息的组件中，注入MessageService并使用getMessage方法订阅消息：

import { Component, OnDestroy } from '@angular/core';
import { Subscription } from 'rxjs';
import { MessageService } from './message.service';

@Component({
  selector: 'app-receiver',
  template: `
    
{{ message }}
  `
})
export class ReceiverComponent implements OnDestroy {
  message: string;
  subscription: Subscription;

  constructor(private messageService: MessageService) {
    this.subscription = this.messageService.getMessage().subscribe(message => {
      this.message = message.text;
    });
  }

  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}

最后，将发送消息和接收消息的组件添加到需要使用全局消息服务的模块中：

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { SenderComponent } from './sender.component';
import { ReceiverComponent } from './receiver.component';

@NgModule({
  imports: [BrowserModule],
  declarations: [SenderComponent, ReceiverComponent],
  providers: [MessageService],
  bootstrap: [SenderComponent, ReceiverComponent]
})
export class AppModule {}

现在，当点击发送消息按钮时，消息将通过全局消息服务发送给接收消息的组件，并在接收组件中显示。