关于Spring 里面Bean的几种初始化、销毁方法（init, destroy）

Dear 丶 2021-09-24 03:58 530阅读 0赞

## 常用的Spring Bean如何指定其初始化和销毁前的方法有以下几种: ##

**1. @PostConstruct @PreDestroy注解方式**

@PostConstruct
       public void init(){ 
       }
       
       @PreDestroy
       public void destroyAn(){ 
       }

**2. 实现 InitializingBean 和 DisposableBean 接口**

public class MyBean implements  InitializingBean, DisposableBean { 
    
       @Override
       public void destroy() throws Exception { 
       	logger.info("DisposableBean destroy...");
       }
    
       @Override
       public void afterPropertiesSet() throws Exception { 
       	logger.info("InitializingBean afterPropertiesSet...");
       }
    }

**3. @Bean实例化方式 指定初始化销毁前方法**

@Bean(initMethod = "init", destroyMethod = "destroy")
      public MyBean myBean(){ 
          return new MyBean ();
      }

## 它们和构造函数一起使用时执行的顺序 ##

写个java例子测试一下，得出如下的顺序结论：

<table> 
 <thead> 
  <tr> 
   <th align="left">执行顺序如下</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">1. 构造函数执行</td> 
  </tr> 
  <tr> 
   <td align="left">2. @PostConstruct</td> 
  </tr> 
  <tr> 
   <td align="left">3. InitializingBean afterPropertiesSet 方法</td> 
  </tr> 
  <tr> 
   <td align="left">4. @Bean initMethod 方法</td> 
  </tr> 
  <tr> 
   <td align="left">5. @PreDestroy</td> 
  </tr> 
  <tr> 
   <td align="left">6. DisposableBean destroy方法</td> 
  </tr> 
  <tr> 
   <td align="left">7. @Bean destroyMethod 方法</td> 
  </tr> 
 </tbody> 
</table>

**测试用例**

package com.middol.mytest.config.beantest;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.DisposableBean;
    import org.springframework.beans.factory.InitializingBean;
    import org.springframework.beans.factory.config.BeanPostProcessor;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.PreDestroy;
    
    /** * 初始化顺序测试 * * @author admin */
    public class MyBeanPostProcessor implements InitializingBean, DisposableBean { 
    
        private Logger logger = LoggerFactory.getLogger(this.getClass());
    
        public MyBeanPostProcessor() { 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor 构造函数执行...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        @PostConstruct
        public void init(){ 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor PostConstruct 函数执行...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        @PreDestroy
        public void destroyAn(){ 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor PreDestroy 函数执行...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        public void beanInit(){ 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor beanInit 函数执行...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        public void beanDestroy(){ 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor beanDestroy 函数执行...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        @Override
        public void destroy() throws Exception { 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor DisposableBean destroy...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    
        @Override
        public void afterPropertiesSet() throws Exception { 
            logger.info("");
            logger.info("++++++++++++++++++++++++++++++++++");
            logger.info("myBeanPostProcessor InitializingBean afterPropertiesSet...");
            logger.info("++++++++++++++++++++++++++++++++++");
        }
    }

package com.middol.mytest.config.beantest;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    /** * 初始化顺序测试 * * @author admin */
    @Configuration
    public class MyBeanPostProcessorConfig { 
    
        @Bean(initMethod = "beanInit", destroyMethod = "beanDestroy")
        public MyBeanPostProcessor myBeanPostProcessor(){ 
            return new MyBeanPostProcessor();
        }
    }