Spring课程 Spring入门篇 4-5 Spring bean装配之基于java的容器注解说明--@Bean

课程链接：

1　　　　解析

1.1　　@bean注解定义

1.2　　@bean注解的使用

2　　　　代码演练

2.1　　@bean的应用不带name

2.2　　@bean的应用带name 

 2.3　　@bean注解调用initMethod和destroyMethod

1　　　　解析

1.1　　@bean注解定义

@bean标识一个用于配置和初始化一个由springIOC容器管理的新对象的方法(生成ioc容器的bean实例)，类似于xml配置的</bean>

1.2　　@bean注解和@Configuration的使用

a　　通常注解@bean和@Configuration使用

b　　@bean(name="",initMethod="",destroyMethod="")(详细使用见代码演练部分)

c　　 @Configuration 该类创建各种Bean交付IoC容器（Bean类代码为纯净JavaBean）

2　　　　代码演练

2.1　　@bean的应用不带name

实体类：

package com.imooc.beanannotation.javabased;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class StoreConfig {

    @Bean
    public Store getStringStore(){
        return new StringStore();
    }

}

测试类：

package com.imooc.test.beanannotation;

import org.junit.Test;

import com.imooc.test.base.UnitTestBase;

public class TestJavaBased extends UnitTestBase{

    public TestJavaBased(){
        super("classpath*:spring-beanannotation.xml");
    }

    @Test
    public void testStoreConfig(){
        System.out.println(super.getbean("getStringStore").getClass().getName());

    }

}

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"
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:component-scan base-package="com.imooc.beanannotation"/>

</beans>

impl类：

package com.imooc.beanannotation.javabased;

public class StringStore implements Store {

}

dao类：

package com.imooc.beanannotation.javabased;

public interface Store {

}

打印结果：

三月 25, 2019 6:44:28 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5a62a404: startup date [Mon Mar 25 06:44:28 CST 2019]; root of context hierarchy
三月 25, 2019 6:44:28 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from URL [file:/F:/xiangmu3/Xin/FuQiang/Spring/ddwei-dao/target/classes/spring-beanannotation.xml]
com.imooc.beanannotation.javabased.StringStore
三月 25, 2019 6:44:29 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@5a62a404: startup date [Mon Mar 25 06:44:28 CST 2019]; root of context hierarchy

2.2　　@bean的应用带name

实体类：

package com.imooc.beanannotation.javabased;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class StoreConfig {

    @Bean(name="store")
    public Store getStringStore(){
        return new StringStore();
    }

}

测试类：

package com.imooc.test.beanannotation;

import org.junit.Test;

import com.imooc.test.base.UnitTestBase;

public class TestJavaBased extends UnitTestBase{

    public TestJavaBased(){
        super("classpath*:spring-beanannotation.xml");
    }

    @Test
    public void testStoreConfig(){
        System.out.println(super.getbean("store").getClass().getName());

    }

}

打印结果：

三月 25, 2019 6:57:00 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@2121052: startup date [Mon Mar 25 06:57:00 CST 2019]; root of context hierarchy
三月 25, 2019 6:57:00 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from URL [file:/F:/xiangmu3/Xin/FuQiang/Spring/ddwei-dao/target/classes/spring-beanannotation.xml]
com.imooc.beanannotation.javabased.StringStore
三月 25, 2019 6:57:01 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@2121052: startup date [Mon Mar 25 06:57:00 CST 2019]; root of context hierarchy

2.3　　bean注解调用initMethod和destroyMethod

实体类：

package com.imooc.beanannotation.javabased;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class StoreConfig {

    @Bean(name="store",initMethod="init",destroyMethod="destroy")
    public Store getStringStore(){
        return new StringStore();
    }

}

impl类：

package com.imooc.beanannotation.javabased;

public class StringStore implements Store {

    public void init(){
        System.out.println("This is init Method");
    }

    public void destroy(){
        System.out.println("This is destroy Method");
    }

}

打印结果：

三月 26, 2019 6:15:23 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5fa34e31: startup date [Tue Mar 26 06:15:23 CST 2019]; root of context hierarchy
三月 26, 2019 6:15:23 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from URL [file:/F:/xiangmu3/Xin/FuQiang/Spring/ddwei-dao/target/classes/spring-beanannotation.xml]
This is init Method
com.imooc.beanannotation.javabased.StringStore
三月 26, 2019 6:15:24 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@5fa34e31: startup date [Tue Mar 26 06:15:23 CST 2019]; root of context hierarchy
This is destroy Method