此篇文章主要演示Spring boot中bean初始化时各个组件的执行顺序，以便开发者能在开发过程中正确选择合适的初始化方式
Bean定义：
package com.example.demo.beandemo;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
public class BeanInitOrder implements InitializingBean, DisposableBean, BeanNameAware, BeanFactoryAware, ApplicationContextAware {
private String name;
public BeanInitOrder() {
System.out.println("执行构造方法");
}
public void initMethod() {
System.out.println("执行bean定义的initMethod方法");
}
public void destroyMethod() {
System.out.println("执行bean定义的destroyMethod方法");
}
@PostConstruct
public void postConstruct() {
System.out.println("执行PostConstruct方法");
}
@PreDestroy
public void preDestroy() {
System.out.println("执行PreDestroy方法");
}
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
System.out.println("注入BeanFactory");
}
public void setBeanName(String s) {
System.out.println("注入BeanName");
}
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
System.out.println("注入ApplicationContext");
}
public void destroy() throws Exception {
System.out.println("执行量DisposableBean的destroy方法");
}
public void afterPropertiesSet() throws Exception {
System.out.println("执行InitializingBean的afterPropertiesSet方法");
}
public void setName(String name){
this.name=name;
}
public String getName() {
return name;
}
}
后置处理器BeanPostProcessor ：
package com.example.demo.beandemo;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class InitBeanHandleBeanPostProcessor implements BeanPostProcessor {
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
if (beanName.equals("getBeanInitOrder")) {
System.out.println("执行BeanPostProcessor的postProcessBeforeInitialization方法");
}
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (beanName.equals("getBeanInitOrder")) {
System.out.println("执行BeanPostProcessor的postProcessAfterInitialization方法");
}
return bean;
}
}
属性处理器BeanFactoryPostProcessor ：
package com.example.demo.beandemo;
import org.springframework.beans.BeansException;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
public class InitBeanHandleBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {BeanDefinition getBeanInitOrder = beanFactory.getBeanDefinition("getBeanInitOrder");
MutablePropertyValues propertyValues = getBeanInitOrder.getPropertyValues();
propertyValues.addPropertyValue("name", "mateEgg");
System.out.println("执行BeanFactoryPostProcessor的postProcessBeanFactory方法");
}
}
配置类：
package com.example.demo.config;
import com.example.demo.beandemo.BeanInitOrder;
import com.example.demo.beandemo.InitBeanHandleBeanPostProcessor;
import com.example.demo.beandemo.InitBeanHandleBeanFactoryPostProcessor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.annotation.PostConstruct;
@Configuration
public class BeanInitOrderConfig {
@Bean(initMethod = "initMethod" ,destroyMethod = "destroyMethod")
public BeanInitOrder getBeanInitOrder(){
return new BeanInitOrder();
}
@Bean
public InitBeanHandleBeanPostProcessor getInitBeanHandle(){
return new InitBeanHandleBeanPostProcessor();
}
@Bean
public static InitBeanHandleBeanFactoryPostProcessor getInitBeanHandleBeanFactoryPostProcessor(){
return new InitBeanHandleBeanFactoryPostProcessor();
}
}
启动类：
package com.example.demo;
import com.example.demo.bean.Car;
import com.example.demo.beandemo.BeanInitOrder;
import com.sun.corba.se.spi.orb.ParserImplBase;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.web.bind.annotation.InitBinder;
import javax.annotation.PostConstruct;
@SpringBootApplication
public class DemoApplication {
@Autowired
private BeanInitOrder beanInitOrder;
public static void main(String[] args) {
ConfigurableApplicationContext run = SpringApplication.run(DemoApplication.class, args);
}
@PostConstruct
public void test(){
System.out.println(beanInitOrder.getName());
}
}
输出结果：
执行BeanFactoryPostProcessor的postProcessBeanFactory方法
2019-01-24 21:59:57.822 INFO 8118 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'beanInitOrderConfig' of type [com.example.demo.config.BeanInitOrderConfig$$EnhancerBySpringCGLIB$$3f223dec] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2019-01-24 21:59:58.137 INFO 8118 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8082 (http)
2019-01-24 21:59:58.159 INFO 8118 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-01-24 21:59:58.160 INFO 8118 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.14]
2019-01-24 21:59:58.167 INFO 8118 --- [ main] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/mac/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2019-01-24 21:59:58.246 INFO 8118 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-01-24 21:59:58.246 INFO 8118 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1493 ms
执行构造方法
注入BeanName
注入BeanFactory
注入ApplicationContext
执行BeanPostProcessor的postProcessBeforeInitialization方法
执行PostConstruct方法
执行InitializingBean的afterPropertiesSet方法
执行bean定义的initMethod方法
执行BeanPostProcessor的postProcessAfterInitialization方法
mateEgg
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