新建一个springBoot项目:

[往期文章：怎么新建一个springBoot项目] https://www.jianshu.com/p/18f5bd189ced

实现初始化器的方式一：

META-INF/spring.factories文件配置

1.新建FirstInitializer实现ApplicationContextInitializer接口
2.在resource下新建META-INF
3.在META-INF下新建spring.factories

方式一实现初始化器.png

方式一实现初始化器.png

FirstInitializer.java源码：

package com.xy.initializer;

import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MapPropertySource;

import java.util.HashMap;
import java.util.Map;
@Order(1)
public class FirstInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        ConfigurableEnvironment environment =applicationContext.getEnvironment();
        Map<String,Object> map = new HashMap<String,Object>();
        map.put("xy","my name is xy!");
        MapPropertySource mapPropertySource = new MapPropertySource("firstInitializer",map);
        environment.getPropertySources().addLast(mapPropertySource);
        System.out.println("FirstInitializer");
    }
}

spring.factories内容：

org.springframework.context.ApplicationContextInitializer=com.xy.initializer.FirstInitializer

方式一实现初始化器测试：

1.新建TestService.java实现ApplicationContextAware接口
2.新建controller方法调用初始化值

新建TestService.java.png

新建controller方法.png

TestService.java源码：

package com.xy.service;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class TestService implements ApplicationContextAware {
    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        System.out.println("test setApplicationContext......");
        this.applicationContext = applicationContext;
    }

    public String test(){
        System.out.println(applicationContext.getBean(DemoService.class));
        DemoService t = applicationContext.getBean(DemoService.class);
        return applicationContext.getEnvironment().getProperty("xy");
    }
}

启动项目查看打印信息：

查看打印信息.png

浏览器访问获取初始化器配置信息：

方式一获取初始化器配置信息.png