Spring中Bean的生命周期

作者：喵喵爱编程 | 2024-08-16 06:11:20

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Spring中Bean的生命周期

#准备工作
最近刚开始看韩顺平老师讲的Spring基础，感觉听起来还是感觉比较好，也就教程中的案例做了实践，接下来记录一下，Spring中Bean的生命周期。
Spring的下载地址（我使用的是3.2.4）：http://repo.springsource.org/libs-release-local/org/springframework/spring/

①创建工程
首先，用IDE创建一个Java工程，在工程目录下创建lib目录，复制需要引用的jar包并添加到ClassPath，因为我用的是Intellij，可能操作上与Eclipse有些不同。
②添加项目依赖Jar包
这个版本和教程中讲的2.5.5也有差异，主要是下载来的jar包中没有一个完整的包可以引用，只有一个个分开的jar包，这就使没有接触过Spring的我有些迷茫，
因为包很多，不知道哪些需要哪些不需要，查了一下资料，说是引用spring-core-3.2.4.RELEASE和spring-beans-3.2.4.RELEASE就够了，但是经过实践，还
需要引入spring-context-3.2.4.RELEASE、spring-expression-3.2.4.RELEASE和写日志的包commons-logging-1.1.1（需要单独下载）。
结论（需要引用的Jar包）：
spring-core-3.2.4.RELEASE | spring-beans-3.2.4.RELEASE | spring-context-3.2.4.RELEASE | spring-expression-3.2.4.RELEASE | commons-logging-1.1.1
③创建applicationContext.xml文件
到这一步又开始迷茫了，搜索一下找到复制过来，Intellij检查到没有使用的引用都是灰色的，所以就删除了未使用的，结果为：

<?xml version="1.0" encoding="utf-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

④创建类文件
User.java

 1 package com.spring.pojo;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.*;
 5 import org.springframework.context.ApplicationContext;
 6 import org.springframework.context.ApplicationContextAware;
 7 
 8 public class User implements BeanNameAware, BeanFactoryAware, ApplicationContextAware, InitializingBean, DisposableBean {
 9 
10     private String name;
11     // private String gender;
12     // private Work service;
13 
14     public User() {
15         System.out.println("①Constructor -> invoked");
16     }
17 
18     public User(String name) {// , String gender, Work service) {
19         this.name = name;
20         // this.gender = gender;
21         // this.service = service;
22     }
23 
24     public String getName() {
25         return name;
26     }
27 
28     public void setName(String name) {
29         System.out.println("①setName -> invoked");
30         this.name = name;
31     }
32 
33     /**
34     public String getGender() {
35         return gender;
36     }
37 
38     public void setGender(String gender) {
39         this.gender = gender;
40     }
41 
42     public Work getService() {
43         return service;
44     }
45 
46     public void setService(Work service) {
47         this.service = service;
48     }
49      */
50 
51     /**
52      * init-method
53      */
54     public void initBean() {
55         System.out.println("①initBean -> invoked");
56     }
57 
58     public void show() {
59         System.out.println("①" + this.name); // + "：" + this.gender + "\r\n" + service.getStatus());
60     }
61 
62     @Override
63     public void setBeanName(String s) {
64         System.out.println("①" + s);
65     }
66 
67     @Override
68     public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
69         System.out.println("①" + applicationContext);
70     }
71 
72     @Override
73     public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
74         System.out.println("①" + beanFactory);
75         Work workService = (Work) beanFactory.getBean("work");
76         String status = workService.getStatus();
77         System.out.println("②" + status);
78     }
79 
80     @Override
81     public void afterPropertiesSet() throws Exception {
82         System.out.println("①afterPropertiesSet -> invoked");
83     }
84 
85     @Override
86     public void destroy() throws Exception {
87         System.out.println("①DisposableBean's destroy -> invoked");
88     }
89 
90     public void beforeDestroy() {
91         System.out.println("①beforeDestroy -> invoked");
92     }
93 }

Work.java

 1 package com.spring.pojo;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.*;
 5 import org.springframework.context.ApplicationContext;
 6 import org.springframework.context.ApplicationContextAware;
 7 
 8 public class Work implements BeanNameAware, BeanFactoryAware, ApplicationContextAware, InitializingBean, DisposableBean {
 9 
10     public String name;
11     public String age;
12 
13     public Work() {
14         System.out.println("②Constructor -> invoked");
15     }
16 
17     public Work(String name, String age) {
18         this.name = name;
19         this.age = age;
20     }
21 
22     public String getName() {
23         return name;
24     }
25 
26     public void setName(String name) {
27         System.out.println("②setName -> invoked");
28         this.name = name;
29     }
30 
31     public String getAge() {
32         return age;
33     }
34 
35     public void setAge(String age) {
36         this.age = age;
37     }
38 
39     public String getStatus() {
40         return this.name + "：" + this.age;
41     }
42 
43     public void initMethod() {
44         System.out.println("②initMethod -> invoked");
45     }
46 
47     @Override
48     public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
49         System.out.println("②" + applicationContext);
50     }
51 
52     @Override
53     public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
54         System.out.println("②" + beanFactory);
55     }
56 
57     @Override
58     public void setBeanName(String s) {
59         System.out.println("②" + s);
60     }
61 
62     @Override
63     public void destroy() throws Exception {
64         System.out.println("②destroy -> invoked");
65     }
66 
67     @Override
68     public void afterPropertiesSet() throws Exception {
69         System.out.println("②afterPropertiesSet");
70     }
71 
72     public void destroyMethod() {
73         System.out.println("②destroyMethod -> invoked");
74     }
75 }

BeanProcessor.java

 1 package com.spring.pojo;
 2 
 3 import org.springframework.beans.BeansException;
 4 import org.springframework.beans.factory.config.BeanPostProcessor;
 5 
 6 public class BeanProcessor implements BeanPostProcessor {
 7 
 8     @Override
 9     public Object postProcessBeforeInitialization(Object o, String s) throws BeansException {
10         System.out.println("postProcessBeforeInitialization -> invoked");
11         return o;
12     }
13 
14     @Override
15     public Object postProcessAfterInitialization(Object o, String s) throws BeansException {
16         System.out.println("postProcessAfterInitialization -> invoked");
17         return o;
18     }
19 }

UserTest.java

 1 package com.spring.pojo;
 2 
 3 import com.spring.pojo.User;
 4 import org.springframework.context.support.AbstractApplicationContext;
 5 import org.springframework.context.support.ClassPathXmlApplicationContext;
 6 
 7 public class UserTest {
 8 
 9     public static void main(String[] args) {
10         AbstractApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
11         User service = (User) context.getBean("user");
12         service.show();
13     }
14 }

applicationContext.xml

<?xml version="1.0" encoding="utf-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.spring.pojo.User"
          scope="prototype"
          init-method="initBean" destroy-method="beforeDestroy">
        <property name="name" value="祁连山"/>
        <!-- <property name="gender" value="男"/>
        <property name="service" ref="workService"/> -->
    </bean>

    <bean id="work" class="com.spring.pojo.Work"
        scope="prototype">
        <property name="name" value="android开发"/>
        <property name="age" value="三年"/>
    </bean>

    <bean id="beanProcessor" class="com.spring.pojo.BeanProcessor"/>
</beans>

⑤测试结果：
①Constructor -> invoked
①setName -> invoked
①user
①org.springframework.beans.factory.support.DefaultListableBeanFactory@3fcd000a: defining beans [user,work,beanProcessor]; root of factory hierarchy
②Constructor -> invoked
②setName -> invoked
②work
②org.springframework.beans.factory.support.DefaultListableBeanFactory@3fcd000a: defining beans [user,work,beanProcessor]; root of factory hierarchy
②org.springframework.context.support.ClassPathXmlApplicationContext@7c4633e7: startup date [Sun Nov 29 13:26:05 CST 2015]; root of context hierarchy
postProcessBeforeInitialization -> invoked
②afterPropertiesSet
postProcessAfterInitialization -> invoked
②android开发：三年
①org.springframework.context.support.ClassPathXmlApplicationContext@7c4633e7: startup date [Sun Nov 29 13:26:05 CST 2015]; root of context hierarchy
postProcessBeforeInitialization -> invoked
①afterPropertiesSet -> invoked
①initBean -> invoked
postProcessAfterInitialization -> invoked
①祁连山

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