lombok的使用案例引入作用域定义singleton单例作用域prototype原型作用域(多例作用域)request请求作用域session会话作用域application全局作用域websocket

设置作用域Spring

dependencygroupIdorg.projectlombok/groupIdartifactIdlombok/artifactIdversion1.18.26/versionscopeprovided/scope

/dependency2.在实体类使用

org.springframework.context.annotation.Bean;

import

org.springframework.stereotype.Component;Component

public

User();user.setId(1);user.setName(张三);return

user;}

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.stereotype.Controller;Controller

public

printUser(){System.out.println(user);User

myUser

user;myUser.setName(悟空);System.out.println(myUser

myUser);System.out.println(user

user);}

org.springframework.stereotype.Controller;

import

javax.annotation.Resource;Controller

public

printUser2(){System.out.println(user

user);}

com.java.demo.controller.UserController;

import

com.java.demo.controller.UserController2;

import

org.springframework.context.ApplicationContext;

import

org.springframework.context.support.ClassPathXmlApplicationContext;public

class

ClassPathXmlApplicationContext(spring-config.xml);UserController

userController

context.getBean(userController,UserController.class);userController.printUser();UserController2

userController2

context.getBean(userController2,UserController2.class);userController2.printUser2();}

User(id1,

org.springframework.context.annotation.Bean;

import

org.springframework.context.annotation.Scope;

import

org.springframework.stereotype.Component;Component

public

User();user.setId(1);user.setName(张三);return

user;}

Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)给出的提示也验证了前面所说的

spring

BeanNameAware、BeanFactoryAware、

的接口方法初始化前置方法。

初始化方法(设置了才会执行)1.注解方式PostConstruct

xml

xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contenthttp://www.springframework.org/schema/contextxsi:schemaLocationhttp://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context

https://www.springframework.org/schema/context/spring-context.xsdcontent:component-scan

base-packagecom.java.demo/content:component-scanbean

idbeanComponentclasscom.java.demo.component.BeanComponent

没有销毁方法。

ClassPathXmlApplicationContext

package

org.springframework.beans.factory.BeanNameAware;

import

javax.annotation.PostConstruct;

import

javax.annotation.PreDestroy;public

class

myInit(){System.out.println(XML

void

postConstruct(){System.out.println(注解

void

doPreDestroy(){System.out.println(do

PreDestroy);}

com.java.demo.component.BeanComponent;

import

org.springframework.context.support.ClassPathXmlApplicationContext;public

class

{ClassPathXmlApplicationContext

context

ClassPathXmlApplicationContext(spring-config.xml);BeanComponent

beanComponent

context.getBean(beanComponent,BeanComponent.class);beanComponent.sayHi();context.destroy();}

}注解初始化方法

不能如果先初始化在初始化代码中如果调用了依赖的属性的方法就会报错(此时依赖的属性还没有注入)。

Bean

的生命周期流程能看到其他的通知初始化前置方法初始化后置方法。

代码如下

package

org.springframework.beans.BeansException;

import

org.springframework.beans.factory.BeanFactory;

import

org.springframework.beans.factory.BeanFactoryAware;

import

org.springframework.beans.factory.BeanNameAware;

import

org.springframework.context.ApplicationContext;

import

org.springframework.context.ApplicationContextAware;

import

javax.annotation.PostConstruct;

import

javax.annotation.PreDestroy;public

class

setApplicationContext(ApplicationContext

applicationContext)

applicationContext);}Overridepublic

void

myInit(){System.out.println(XML

void

postConstruct(){System.out.println(注解

void

doPreDestroy(){System.out.println(do

com.java.demo;import

org.springframework.beans.BeansException;

import

org.springframework.beans.factory.config.BeanPostProcessor;public

class

postProcessBeforeInitialization(Object

bean,

{System.out.println(postProcessBeforeInitialization

beanName

postProcessAfterInitialization(Object

bean,

{System.out.println(postProcessAfterInitialization

beanName

xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contenthttp://www.springframework.org/schema/contextxsi:schemaLocationhttp://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans.xsd

http://www.springframework.org/schema/context

https://www.springframework.org/schema/context/spring-context.xsdcontent:component-scan

base-packagecom.java.demo/content:component-scanbean

idbeanComponentclasscom.java.demo.component.BeanComponent

init-methodmyInit

idmyBeanPostProcessorclasscom.java.demo.MyBeanPostProcessor/bean

/beanspackage

com.java.demo.component.BeanComponent;

import

org.springframework.context.support.ClassPathXmlApplicationContext;public

class

{ClassPathXmlApplicationContext

context

ClassPathXmlApplicationContext(spring-config.xml);BeanComponent

beanComponent

context.getBean(beanComponent,BeanComponent.class);beanComponent.sayHi();context.destroy();//context.close();}