哪个先执行：@PostConstruct和@Bean的initMethod？

结论：

/**
* step1:执行构造函数
* step2:执行使用@PostConstruct注解修饰的方法【如果有多个，则执行顺序不确定】
* step3:执行@Bean注解中initMethod指定的方法
*/

示例代码：

@Slf4j
public class InitBean {

    public InitBean() {
        log.info("Step1:begin to execute Constructor Function");
    }

    public void initMethod() {
        log.info("Step3:begin to execute initMethod");
    }


    @PostConstruct
    public void postConstructMethod1() {
        log.info("Step2:begin to execute  postConstructMethod1 with @PostConstruct");
    }

    @PostConstruct
    public void postConstructMethod2() {
        log.info("Step2:begin to execute postConstructMethod2 with @PostConstruct");
    }

}

Java Config方式进行Bean的初始化：

@Configuration
public class InitBeanConfig {

    @Bean(initMethod = "initMethod")
    public InitBean initBean() {
        return new InitBean();
    }

}

测试用例：

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = InitBeanConfig.class)
public class InitBeanConfigTest {

    @Test
    public void givenBean_WhenInit_thenFirstConstructorFunction_SecondPostConstructAnna_ThirdInitMethod() {
        /**
         * step1:执行构造函数
         * step2:执行使用@PostConstruct注解修饰的方法
         * step3:执行@Bean注解中initMethod指定的方法
         */
    }

}

执行结果：

2019-01-06 22:16:03.362 INFO 21944 --- [main] c.t.learning.init.spring.InitBean : Step1:begin to execute Constructor Function
2019-01-06 22:16:03.377 INFO 21944 --- [main] c.t.learning.init.spring.InitBean : Step2:begin to execute postConstructMethod1 with @PostConstruct
2019-01-06 22:16:03.378 INFO 21944 --- [main] c.t.learning.init.spring.InitBean : Step2:begin to execute postConstructMethod2 with @PostConstruct
2019-01-06 22:16:03.378 INFO 21944 --- [main] c.t.learning.init.spring.InitBean : Step3:begin to execute initMethod
2019-01-06 22:16:03.461 INFO 21944 --- [main] c.t.l.init.spring.InitBeanConfigTest: Started InitBeanConfigTest in 3.548 seconds (JVM running for 5.781)

温馨提示：如果存在多个使用注解@PostConstruct修饰的方法，则这些方法执行顺序不确定

代码：
https://github.com/helloworldtang/spring-boot-cookbook/blob/v1.0.2-thymeleaf/learning-demo/src/main/java/com/tangcheng/learning/init/spring/InitBean.java