如果餓了就吃,困了就睡,渴了就喝,人生就太無趣了
源碼地址:https://github.com/keer123456789/springbootstudy/tree/master/befor_run_demo
第一種:@PostConstruct
@Configuration
public class MyConfig_1 {
@PostConstruct
public void test() {
System.out.println("===================Service 1====================");
}
}
啓動運行項目:
第二種 實現InitializingBean接口
@Configuration
public class MyConfig_2 implements InitializingBean {
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("===================Service 2====================");
}
}
啓動運行項目:
第三種 實現BeanPostProcessor接口
@Configuration
public class MyConfig_3 implements BeanPostProcessor {
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println("===================Service 3====================");
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
}
啓動運行項目:(目前輸出多次的Service3,每太搞清楚,歡迎指導,會繼續學習)
第四種 在啓動類run之前執行方法
這種方法不太可取!
@SpringBootApplication
public class BeforRunDemoApplication {
public static void main(String[] args) {
System.out.println("===================Service 5====================");
SpringApplication.run(BeforRunDemoApplication.class, args);
}
}
啓動項目:
四種方式的啓動順序
啓動類前->BeanPostProcessor->@PostConstruct->InitializingBean
值得注意的是第三種方式,他可以讓實現類裏的方法提前執行
@Configuration
public class MyConfig_1 {
@PostConstruct
public void test() {
System.out.println("===================Service 1====================");
}
}
@Configuration
public class MyConfig_4 implements BeanPostProcessor {
@PostConstruct
public void test(){
System.out.println("===================Service 4====================");
}
}
啓動項目: