Spring基础：快速入门spring（7）：bean的lifecyle

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#spring #lifecyle #init #destroy

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本文详细介绍了Spring框架中Bean的生命周期，包括初始化和销毁的过程。通过一个具体的示例演示了如何自定义初始化(init-method)和销毁(destroy-method)方法，并展示了这些方法在Spring上下文中是如何被调用的。

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在这篇文章中我们会了解一下spring中bean的lifecycle，并且在例子中实现自定义init-method和destroy-method。

这里写图片描述

bean的生命周期

在spring中，bean的lifecyle大体如下所示

这里写图片描述

自定义init-method和destroy-method

package com.liumiao.demo.spring;

public class Student implements Person {
    private String name;
    private String country;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        System.out.println("Student: set method: SetName:"+name);
        this.name = name;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        System.out.println("Student: set method: SetCountry:"+country);
        this.country = country;
    }

    private TeachingService teachingService;
    public Student(){
        System.out.println("Student Default construct is called...");
    }

    public void initMethod(){
        System.out.println("User customized init-method is called");
    }
    public void destroyMethod(){
        System.out.println("User customized destroy-method is called");
    }
    public void setTeachingService(TeachingService service){
        teachingService=service;
    }
    @Override
    public String sayhello(){
        return "Hello, I am a student.";
    }
    @Override
    public String provideTeachingService(){
        return "I teach how to study...";
    }
}

修改spring设定文件，设定自定义的函数

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <context:property-placeholder location="classpath:com/liumiao/demo/spring/Person.properties" />
    <bean id="thePerson" class="com.liumiao.demo.spring.Student" init-method="initMethod" destroy-method="destroyMethod">
        <property name="teachingService" ref="theService"></property>
        <property name="name" value="${person.name}" />
        <property name="country" value="${person.country}" />
    </bean>

    <bean id="theService" class="com.liumiao.demo.spring.SwimmingTeachingService">
    </bean>

</beans>

执行结果

重执行结果中可以大体看到spring机制运行时候是如何加载自定义的函数的

十一月 27, 2016 8:51:27 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@25f38edc: startup date [Sun Nov 27 08:51:27 CST 2016]; root of context hierarchy
十一月 27, 2016 8:51:27 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [com/liumiao/demo/spring/spring-cfg.xml]
十一月 27, 2016 8:51:28 上午 org.springframework.context.support.PropertySourcesPlaceholderConfigurer loadProperties
信息: Loading properties file from class path resource [com/liumiao/demo/spring/Person.properties]
Student Default construct is called...
Student: set method: SetName:liumiao.cn
Student: set method: SetCountry:ChinaPRC
User customized init-method is called
十一月 27, 2016 8:51:28 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@25f38edc: startup date [Sun Nov 27 08:51:27 CST 2016]; root of context hierarchy
Hello, I am a student.
I teach how to study...
ChinaPRC
liumiao.cn
User customized destroy-method is called