environment與@ConfigurationProperties的關系 加載過程分析

 

 environment是在printBanner之前就初始化好了, 更在context創建之前, 

已經加載application-xxxx.properties, System.properties, System.environment ...

也可以自己監聽應用啟動 SpringApplicationRunListener事件， 完成自己的獨特的配置加載方案

啟動后調用listener.finished() 打印一些啟動后的信息

 

prepareEnvironment()源碼如下

    private ConfigurableEnvironment prepareEnvironment(
            SpringApplicationRunListeners listeners,
            ApplicationArguments applicationArguments) {
        // Create and configure the environment
        ConfigurableEnvironment environment = getOrCreateEnvironment();

//加載標准目錄下的配置文件 &profile
        configureEnvironment(environment, applicationArguments.getSourceArgs());
//加載自定義的配置方案
        listeners.environmentPrepared(environment);
        if (!this.webEnvironment) {
            environment = new EnvironmentConverter(getClassLoader())
                    .convertToStandardEnvironmentIfNecessary(environment);
        }
        return environment;
    }

 

 

 

@ConfigurationProperties  使用的變量也是從environment中取的

 

 CLI參數配置方式：

 

 

 

 

 

參考：

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html#boot-features-external-config-relaxed-binding

https://www.baeldung.com/properties-with-spring