# Application Listeners org.springframework.context.ApplicationListener=\ org.springframework.boot.context.config.ConfigFileApplicationListener,\
一、SmartApplicationListener介绍
/** * 指定支持哪些类型的事件 */ boolean supportsEventType(Class<? extends ApplicationEvent> var1); /** * 指定支持发生事件所在的类型 */ boolean supportsSourceType(Class<?> var1);
如何在 SmartApplicationListener 实现监听解耦
1、我们只需在加载完成之后去加入一个监听器。
2、继承SmartApplicationListener接口
3、设置order属性决定监听器的顺序 ConfigFileApplicationListener.DEFAULT_ORDER + 1
4、将application.yml内容读取之后并修改
二、ConfigFileApplicationListener
三、最终结果：
public class AfterConfigListener implements SmartApplicationListener,Ordered {
public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
return ApplicationEnvironmentPreparedEvent.class.isAssignableFrom(eventType) || ApplicationPreparedEvent.class.isAssignableFrom(eventType);
}
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof ApplicationEnvironmentPreparedEvent) {
}
if (event instanceof ApplicationPreparedEvent) {
}
}
@Override
public int getOrder() {
// 写在加载配置文件之后
return ConfigFileApplicationListener.DEFAULT_ORDER + 1;
}
}
public class AfterConfigListener implements SmartApplicationListener,Ordered {
// 复制的ConfigFileApplicationListener文件内容
public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
return ApplicationEnvironmentPreparedEvent.class.isAssignableFrom(eventType) || ApplicationPreparedEvent.class.isAssignableFrom(eventType);
}
public void onApplicationEvent(ApplicationEvent event) {
// ApplicationEnvironmentPreparedEvent 是加载配置文件，初始化日志系统的事件。
if (event instanceof ApplicationEnvironmentPreparedEvent) {
// 获得原来的password内容
String password = ((ApplicationEnvironmentPreparedEvent) event).getEnvironment().getProperty("spring.datasource.password");
// 进行密码的解密
System.setProperty("spring.datasource.password", SM4Utils.encryptData_ECB(password));
}
if (event instanceof ApplicationPreparedEvent) {
}
}
@Override
public int getOrder() {
// 设置该监听器 在加载配置文件之后执行
return ConfigFileApplicationListener.DEFAULT_ORDER + 1;
}
}
public class Application {
public static void main(String[] args) {
SpringApplication springApplication = new SpringApplication(Application.class);
springApplication.addListeners(new AfterConfigListener());
springApplication.run(args);
}
}
