springboot框架在容器加载完成之后执行某个方法

问题描述：

想在websocket实现的Handler中执行一些初始化操作，但是初始化操作使用到了@Autowired自动注入的变量，而且是保护类型。第一个想法是放到Handler构造函数中执行，但是@Autowired注入的变量为null，故此方法不可行。

问题解决

解决方法一

在Application启动类中实现ApplicationListener接口，这个接口支持的ApplicationReadyEvent事件在上下文已经准备完毕的时候触发。

代码如下

/*

 * Copyright 2018 Kurento (https://www.kurento.org)

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package org.kurento.tutorial.rtpreceiver;

import org.kurento.client.KurentoClient;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.context.event.ApplicationReadyEvent;

import org.springframework.boot.web.servlet.ServletContextInitializer;

import org.springframework.context.ApplicationListener;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.socket.config.annotation.EnableWebSocket;

import org.springframework.web.socket.config.annotation.WebSocketConfigurer;

import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

import org.springframework.web.socket.server.standard.ServletServerContainerFactoryBean;

/**

 * Kurento Java Tutorial - Main Application class.

 */

@SpringBootApplication

@EnableWebSocket

@Configuration

public class Application implements WebSocketConfigurer

{ //, ApplicationListener<ApplicationReadyEvent>

  @Bean

  public Handler handler()

  {

    return new Handler();

  }

  @Bean

  public KurentoClient kurentoClient()

  {

    return KurentoClient.create();

  }

  @Override

  public void registerWebSocketHandlers(WebSocketHandlerRegistry registry)

  {

    String[] allowsOrigins = {"*"};

    registry.addHandler(handler(), "/rtpreceiver").setAllowedOrigins(allowsOrigins);

    //registry.addHandler(handler(), "/rtpreceiver");

  }

  public static void main(String[] args) throws Exception

  {

    SpringApplication.run(Application.class, args);

  }

  @Override

  public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {

    try {

      System.out.println("all is ok");

      // 在此处调用其他类中需要执行的方法

    } catch (Exception e) {

      System.out.println("[项目启动时调用g1] 发生错误,");

    }

  }

}

// 问是，我的Handler也是@Bean形式注入，不知道怎么调用Handler类中的方法……

解决方法二

直接在Handler类中利用@PostConstruct注解方式，PostConstruct注释用于在依赖关系注入完成之后需要执行的方法上，以执行任何初始化。

 @PostConstruct

  private void pushflow(){

    // 执行操作即可。

  }