Spring之BeanFactory和ApplicationContext
- 类图
- BeanFactory
- 概述
- 功能
- 项目结构
- 项目代码
- 运行结果
- 总结
- ApplicationContext
- 概述
- 功能
- MessageSource(国际化的支持)
- 概述
- 项目结构
- 项目代码
- 运行结果
- ResourcePatternResolver(匹配资源路径)
- 概述
- 项目结构
- 项目代码
- 运行结果
- EnvironmentCapable(环境变量配置)
- 项目结构
- 项目代码
- 运行结果
- ApplicationEventPublisher(事件发布)
- 项目结构
- 项目代码
- 运行结果
- ApplicationContext实现类
- 基于XML方式
- 项目结构
- 项目代码
- 运行结果
- 基于磁盘目录XML方式
- 项目结构
- 项目代码
- 运行结果
- 基于注解方式
- @Import
- 项目结构
- 项目代码
- 运行结果
- @Conditional
- 项目结构
- 项目代码
- 运行结果
类图
BeanFactory
概述
- BeanFactory,以Factory结尾,表示它是一个工厂类(接口), 它是负责生产和管理bean的一个工厂。在Spring中,BeanFactory是IOC容器的核心接口,它的职责包括:实例化、定位、配置应用程序中的对象及建立这些对象间的依赖;
- BeanFactory只是个接口,并不是IOC容器的具体实现,但是Spring容器给出了很多种实现,如DefaultListableBeanFactory、XmlBeanFactory、ApplicationContext等,其中XmlBeanFactory就是常用的一种,该实现将以XML方式描述组成应用的对象及对象间的依赖关系。XmlBeanFactory类将持有此XML配置元数据,并用它来构建一个完全可配置的系统或应用;
- 它为其他具体的IOC容器提供了最基本的规范,例如DefaultListableBeanFactory、XmlBeanFactory、ApplicationContext等具体的容器都是实现了BeanFactory,再在其基础之上附加了其他的功能;
- 原始的BeanFactory无法支持Spring的许多插件,如AOP功能、Web应用等。ApplicationContext接口,它由BeanFactory接口派生而来。现在一般使用ApplicationnContext,其不但包含了BeanFactory的作用,同时还进行更多的扩展;
功能
项目结构
项目代码
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com</groupId><artifactId>spring-bean-factory</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>5.2.1.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>5.2.1.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.1.RELEASE</version></dependency></dependencies></project>
AutowireBean.java
package com.spring.bean;/*** @author honey* @date 2023-08-10 14:51:07*/
public class AutowireBean {public void autowire(){System.out.println("AutowireBean==autowire()");}
}
UserBean.java
package com.spring.bean;import org.springframework.beans.factory.annotation.Autowired;/*** @author honey* @date 2023-08-10 14:08:14*/
public class UserBean {@Autowiredprivate AutowireBean autowireBean;public void to() {System.out.println("UserBean==to()");autowireBean.autowire();}
}
SpringConfig.java
package com.spring.config;import com.spring.bean.AutowireBean;
import com.spring.bean.UserBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;/*** @author honey* @date 2023-08-10 14:08:44*/
@Configuration
public class SpringConfig {@Beanpublic UserBean userBean(){return new UserBean();}@Beanpublic AutowireBean autowireBean(){return new AutowireBean();}
}
SpringTest01.java
package com.spring.test;import com.spring.bean.UserBean;
import com.spring.config.SpringConfig;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.annotation.AnnotationConfigUtils;import java.util.Arrays;
import java.util.Collection;/*** @author honey* @date 2023-08-10 14:09:39*/
public class SpringTest01 {public static void main(String[] args) {// 初始化BeanFactoryDefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();// 获取SpringConfig对应的BeanDefinitionAbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.genericBeanDefinition(SpringConfig.class).getBeanDefinition();// 将BeanDefinition注册到BeanFactory中beanFactory.registerBeanDefinition("springConfig", beanDefinition);// 注册注解相关配置的处理器AnnotationConfigUtils.registerAnnotationConfigProcessors(beanFactory);// 通过BeanFactory后置处理器处理SpringConfig中配置的bean(ConfigurationClassPostProcessor)Collection<BeanFactoryPostProcessor> beanFactoryPostProcessors = beanFactory.getBeansOfType(BeanFactoryPostProcessor.class).values();beanFactoryPostProcessors.forEach((beanFactoryPostProcessor) -> beanFactoryPostProcessor.postProcessBeanFactory(beanFactory));// 通过Bean对象后置处理器处理依赖注入@Autowired(AutowiredAnnotationBeanPostProcessor)和@Resource(CommonAnnotationBeanPostProcessor)Collection<BeanPostProcessor> beanPostProcessors = beanFactory.getBeansOfType(BeanPostProcessor.class).values();beanPostProcessors.forEach(beanFactory::addBeanPostProcessor);// 提前初始化单例对象(饿汉式)beanFactory.preInstantiateSingletons();// 默认情况下延迟加载(懒汉式)UserBean userBean = beanFactory.getBean("userBean", UserBean.class);userBean.to();System.out.println(userBean);System.out.println("-------------");// 输出所有注册到BeanFactory中的beanNameArrays.stream(beanFactory.getBeanDefinitionNames()).forEach((beanName) -> System.out.println("beanName:" + beanName));}
}
运行结果
总结
DefaultListableBeanFactory作为BeanFactory的默认实现类,该类中维护了存储Bean对象的map集合,BeanFactory主要负责生产和管理Bean对象。
// 注册注解相关配置的处理器
AnnotationConfigUtils.registerAnnotationConfigProcessors(beanFactory);
AnnotationConfigUtils.java
// 通过BeanFactory后置处理器处理SpringConfig中配置的bean(ConfigurationClassPostProcessor)
Collection<BeanFactoryPostProcessor> beanFactoryPostProcessors = beanFactory.getBeansOfType(BeanFactoryPostProcessor.class).values();
beanFactoryPostProcessors.forEach((beanFactoryPostProcessor) -> beanFactoryPostProcessor.postProcessBeanFactory(beanFactory)
);
ConfigurationClassPostProcessor:用于从BeanFactory中检测使用了@Configuration注解的类,并将这些类中使用了@Bean注解的方法生成BeanDefinition,注册到BeanFactory中。
ConfigurationClassPostProcessor.java
EventListenerMethodProcessor:主要用于处理@EventListener注解。
// 通过Bean对象后置处理器处理依赖注入@Autowired(AutowiredAnnotationBeanPostProcessor)和@Resource(CommonAnnotationBeanPostProcessor)
Collection<BeanPostProcessor> beanPostProcessors = beanFactory.getBeansOfType(BeanPostProcessor.class).values();
beanPostProcessors.forEach(beanFactory::addBeanPostProcessor
);
AutowiredAnnotationBeanPostProcessor: 主要用于处理@Autowired注解。
AutowiredAnnotationBeanPostProcessor.java
CommonAnnotationBeanPostProcessor:主要用于处理@Resource注解。
CommonAnnotationBeanPostProcessor.java
// 提前初始化单例对象(饿汉式)
beanFactory.preInstantiateSingletons();
BeanFactory默认采用延迟加载的形式来注入Bean。
BeanFactoryPostProcessor:BeanFactory的后置处理器,是实现spring容器功能扩展的重要接口;
BeanPostProcessor:Bean对象的后置处理器,负责对已创建好的bean对象进行加工处理;
BeanPostProcessor中的两个核心方法:
postProcessBeforeInitialization:在任何初始化方法执行之前执行该方法,如InitializingBean的afterPropertiesSet方法;
postProcessAfterInitialization:在任何初始化方法执行之后执行该方法,如InitializingBean的afterPropertiesSet方法;
ApplicationContext
概述
ApplicationContext的中文意思是“应用程序上下文”,它继承自BeanFactory接口,除了包含BeanFactory的所有功能之外,在国际化支持、资源访问(如URL和文件)、事件传播等方面进行了良好的支持,被推荐为Java EE应用之首选,可应用在Java APP与Java Web中。
- MessageSource(国际化的支持)
- ResourcePatternResolver(匹配资源路径)
- EnvironmentCapable(环境变量配置)
- ApplicationEventPublisher(事件发布)
功能
MessageSource(国际化的支持)
概述
MessageSource是Spring中的转换消息接口,提供了国际化信息的能力。MessageSource用于解析消息,并支持消息的参数化和国际化。Spring包含两个内置的MessageSource实现:ResourceBundleMessageSource和ReloadableResourceBundleMessageSource。
项目结构
项目代码
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com</groupId><artifactId>spring-application-context</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><dependencies><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>5.2.1.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>5.2.1.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.1.RELEASE</version></dependency></dependencies></project>
SpringConfig.java
package com.spring.config;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ResourceBundleMessageSource;/*** @author honey* @date 2023-08-11 01:30:48*/
@Configuration
public class SpringConfig {@Beanpublic ResourceBundleMessageSource messageSource() {ResourceBundleMessageSource source = new ResourceBundleMessageSource();// 设置基础名source.setBasenames("messages/message");// 设置编码source.setDefaultEncoding("UTF-8");return source;}
}
在resources目录下创建文件夹messages,并在messages文件夹下新增两个配置文件,分别是message_en.properties和message_zh.properties。
message_en.properties
test=test
message_zh.properties
test=测试
SpringTest01.java
package com.spring.test;import com.spring.config.SpringConfig;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ResourceBundleMessageSource;import java.util.Locale;/*** @author honey* @date 2023-08-11 01:33:10*/
public class SpringTest01 {public static void main(String[] args) {// MessageSource(国际化的支持)AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(SpringConfig.class);ResourceBundleMessageSource messageSource = applicationContext.getBean("messageSource", ResourceBundleMessageSource.class);System.out.println("中文:" + messageSource.getMessage("test", null, Locale.CHINESE));System.out.println("英文:" + messageSource.getMessage("test", null, Locale.ENGLISH));}
}
运行结果
ResourcePatternResolver(匹配资源路径)
概述
ResourcePatternResolver用于解析带有*等通配符路径的资源文件,是ResourceLoader接口的拓展接口。
classpath: 只会从target/classes目录下查找文件;
classpath*: 不仅会从target/classes目录下查找文件,还会从所依赖的Jar包中查找文件;
项目结构
项目代码
application.properties
name=honey
SpringTest02.java
package com.spring.test;import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.core.io.Resource;import java.io.IOException;
import java.util.Arrays;/*** @author honey* @date 2023-08-11 02:09:51*/
public class SpringTest02 {public static void main(String[] args) throws IOException {// ResourcePatternResolver(匹配资源路径)AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();System.out.println("-------------------------------------------------------------");System.out.println("读取resources目录下的application.properties");Resource[] resources1 = applicationContext.getResources("classpath:application.properties");Arrays.stream(resources1).forEach(System.out::println);System.out.println("-------------------------------------------------------------");System.out.println("读取spring-beans-5.2.1.RELEASE.jar!/META-INF/spring.factories");Resource[] resources2 = applicationContext.getResources("classpath*:META-INF/spring.factories");Arrays.stream(resources2).forEach(System.out::println);}
}
运行结果
EnvironmentCapable(环境变量配置)
项目结构
项目代码
SpringTest03.java
package com.spring.test;import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;/*** @author honey* @date 2023-08-11 02:31:12*/
public class SpringTest03 {public static void main(String[] args) {// EnvironmentCapable(环境变量配置)AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();ConfigurableEnvironment environment = applicationContext.getEnvironment();String javaHome = environment.getProperty("java_home");String env = environment.getProperty("env");System.out.println("java_home:" + javaHome);System.out.println("env:" + env);}
}
运行结果
在启动时需要加上环境变量参数
方式一
方式二
ApplicationEventPublisher(事件发布)
项目结构
项目代码
UserInfoEvent.java
package com.spring.event;import org.springframework.context.ApplicationEvent;/*** @author honey* @date 2023-08-11 02:42:37*/
public class UserInfoEvent extends ApplicationEvent {/*** source事件源** @param source source*/public UserInfoEvent(Object source) {super(source);}
}
EmailListener.java
package com.spring.listener;import com.spring.event.UserInfoEvent;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;/*** @author honey* @date 2023-08-11 02:44:35*/
@Component
public class EmailListener {@EventListenerpublic void emailListener(UserInfoEvent userInfoEvent) {System.out.println("当前监听器:emailListener,userInfoEvent:" + userInfoEvent);}
}
PhoneListener.java
package com.spring.listener;import com.spring.event.UserInfoEvent;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;/*** @author honey* @date 2023-08-11 02:46:40*/
@Component
public class PhoneListener {@EventListenerpublic void phoneListener(UserInfoEvent userInfoEvent) {System.out.println("当前监听器:phoneListener,userInfoEvent:" + userInfoEvent);}
}
SpringConfig02.java
package com.spring.config;import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;/*** @author honey* @date 2023-08-11 02:48:54*/
@Configuration
@ComponentScan(value = {"com.spring.listener"})
public class SpringConfig02 {
}
SpringTest04.java
package com.spring.test;import com.spring.config.SpringConfig02;
import com.spring.event.UserInfoEvent;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;/*** @author honey* @date 2023-08-11 02:47:25*/
public class SpringTest04 {public static void main(String[] args) {// ApplicationEventPublisher(事件发布)AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(SpringConfig02.class);applicationContext.publishEvent(new UserInfoEvent(applicationContext));}
}
运行结果
ApplicationContext实现类
基于XML方式
项目结构
项目代码
UserBean.java
package com.spring.bean;/*** @author honey* @date 2023-08-11 03:11:09*/
public class UserBean {
}
spring.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="userBean" class="com.spring.bean.UserBean"/></beans>
SpringTest05.java
package com.spring.test;import com.spring.bean.UserBean;
import org.springframework.context.support.ClassPathXmlApplicationContext;/*** @author honey* @date 2023-08-11 03:11:51*/
public class SpringTest05 {public static void main(String[] args) {// 读取spring.xmlClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");// 从IOC容器中读取对象UserBean userBean = applicationContext.getBean("userBean", UserBean.class);System.out.println(userBean);}
}
运行结果
基于磁盘目录XML方式
项目结构
项目代码
SpringTest06.java
package com.spring.test;import com.spring.bean.UserBean;
import org.springframework.context.support.FileSystemXmlApplicationContext;/*** @author honey* @date 2023-08-11 03:17:20*/
public class SpringTest06 {public static void main(String[] args) {// 从磁盘中读取spring.xmlFileSystemXmlApplicationContext applicationContext = new FileSystemXmlApplicationContext("F:\\spring.xml");// 从IOC容器中读取对象UserBean userBean = applicationContext.getBean("userBean", UserBean.class);System.out.println(userBean);}
}
运行结果
基于注解方式
- @Configuration:配置类
- @ComponentScan:扫描指定包中加上了@Controller/@Service/@Reponsitory/@Component等注解的类
- @Bean:beanId默认为方法名称
- @Import:beanId默认为类的全限定名
4.1. @Import({A.class,B.class})
4.2. @Import (MyImportSelector.class),其中MyImportSelector实现了ImportSelector接口
4.3. @Import (MyImportBeanDefinitionRegistrar.class),其中MyImportBeanDefinitionRegistrar实现了ImportBeanDefinitionRegistrar接口 - @Scope:设置作用域(singleton、prototype、request、session)
- @Lazy:设置单例对象是否懒加载
- @Conditional:根据指定条件判断Bean对象是否加载到IOC容器中
@Import
项目结构
项目代码
SpringConfig03.java
package com.spring.config;import com.spring.bean.UserBean;
import org.springframework.context.annotation.Bean;/*** @author honey* @date 2023-08-11 03:53:02*/
public class SpringConfig03 {@Beanpublic UserBean userBean03() {return new UserBean();}
}
SpringConfig04.java
package com.spring.config;import com.spring.bean.UserBean;
import org.springframework.context.annotation.Bean;/*** @author honey* @date 2023-08-11 03:54:27*/
public class SpringConfig04 {@Beanpublic UserBean userBean04() {return new UserBean();}
}
MyImportSelector.java
package com.spring.bean;import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;/*** @author honey* @date 2023-08-11 03:55:37*/
public class MyImportSelector implements ImportSelector {@Overridepublic String[] selectImports(AnnotationMetadata importingClassMetadata) {return new String[]{"com.spring.config.SpringConfig04"};}
}
MyImportBeanDefinitionRegistrar.java
package com.spring.bean;import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;/*** @author honey* @date 2023-08-11 03:55:45*/
public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {@Overridepublic void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {RootBeanDefinition rootBeanDefinition = new RootBeanDefinition(UserBean.class);registry.registerBeanDefinition("userBean05", rootBeanDefinition);}
}
SpringConfig05.java
package com.spring.config;import com.spring.bean.MyImportBeanDefinitionRegistrar;
import com.spring.bean.MyImportSelector;
import org.springframework.context.annotation.Import;/*** @author honey* @date 2023-08-11 04:02:27*/
@Import({SpringConfig03.class, MyImportSelector.class, MyImportBeanDefinitionRegistrar.class})
public class SpringConfig05 {}
SpringTest07.java
package com.spring.test;import com.spring.bean.UserBean;
import com.spring.config.SpringConfig05;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;/*** @author honey* @date 2023-08-11 04:06:39*/
public class SpringTest07 {public static void main(String[] args) {AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(SpringConfig05.class);UserBean userBean03 = annotationConfigApplicationContext.getBean("userBean03", UserBean.class);System.out.println(userBean03);UserBean userBean04 = annotationConfigApplicationContext.getBean("userBean04", UserBean.class);System.out.println(userBean04);UserBean userBean05 = annotationConfigApplicationContext.getBean("userBean05", UserBean.class);System.out.println(userBean05);}
}
运行结果
@Conditional
项目结构
项目代码
LinuxCondition.java
package com.spring.condition;import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;/*** @author honey* @date 2023-08-11 04:20:37*/
public class LinuxCondition implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {return System.getProperty("os.name").toLowerCase().contains("linux");}
}
WindowsCondition.java
package com.spring.condition;import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;/*** @author honey* @date 2023-08-11 04:22:04*/
public class WindowsCondition implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {return System.getProperty("os.name").toLowerCase().contains("windows");}
}
SystemOperation.java
package com.spring.condition;/*** @author honey* @date 2023-08-11 04:22:49*/
public class SystemOperation {private final String name;public SystemOperation(String name) {this.name = name;}@Overridepublic String toString() {return "SystemOperation{" +"name='" + name + '\'' +'}';}
}
SpringConfig06.java
package com.spring.config;import com.spring.condition.LinuxCondition;
import com.spring.condition.SystemOperation;
import com.spring.condition.WindowsCondition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;/*** @author honey* @date 2023-08-11 04:23:27*/
public class SpringConfig06 {@Bean@Conditional(value = WindowsCondition.class)public SystemOperation windowsSystemOperation() {return new SystemOperation("执行windows命令");}@Bean@Conditional(value = LinuxCondition.class)public SystemOperation linuxSystemOperation() {return new SystemOperation("执行linux命令");}
}
SpringTest08.java
package com.spring.test;import com.spring.condition.SystemOperation;
import com.spring.config.SpringConfig06;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;import java.util.Map;/*** @author honey* @date 2023-08-11 04:24:39*/
public class SpringTest08 {public static void main(String[] args) {AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(SpringConfig06.class);Map<String, SystemOperation> beansOfType = annotationConfigApplicationContext.getBeansOfType(SystemOperation.class);System.out.println(beansOfType);}
}