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[转]Spring注解-@Configuration注解、@Bean注解以及配置自动扫描、bean作用域

时间:2017-04-08 11:22:04      阅读:224      评论:0      收藏:0      [点我收藏+]

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1、@Configuration标注在类上,相当于把该类作为spring的xml配置文件中的<beans>,作用为:配置spring容器(应用上下文)

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package com.test.spring.support.configuration;

@Configuration
public class TestConfiguration {
    public TestConfiguration(){
        System.out.println("spring容器启动初始化。。。");
    }
}
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相当于:

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<?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" xmlns:jdbc="http://www.springframework.org/schema/jdbc"  
    xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util" xmlns:task="http://www.springframework.org/schema/task" xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd
        http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.0.xsd" default-lazy-init="false">


</beans>
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主方法进行测试:

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package com.test.spring.support.configuration;

public class TestMain {
    public static void main(String[] args) {

        //@Configuration注解的spring容器加载方式,用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext
        ApplicationContext context = new AnnotationConfigApplicationContext(TestConfiguration.class);

        //如果加载spring-context.xml文件:
        //ApplicationContext context = new ClassPathXmlApplicationContext("spring-context.xml");
    }
}
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从运行主方法结果可以看出,spring容器已经启动了:

八月 11, 2016 12:04:11 下午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@203e25d3: startup date [Thu Aug 11 12:04:11 CST 2016]; root of context hierarchy
spring容器启动初始化。。。

 


2、@Bean标注在方法上(返回某个实例的方法),等价于spring的xml配置文件中的<bean>,作用为:注册bean对象

bean类:

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package com.test.spring.support.configuration;

public class TestBean {

    public void sayHello(){
        System.out.println("TestBean sayHello...");
    }

    public String toString(){
        return "username:"+this.username+",url:"+this.url+",password:"+this.password;
    }

    public void start(){
        System.out.println("TestBean 初始化。。。");
    }

    public void cleanUp(){
        System.out.println("TestBean 销毁。。。");
    }
}
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配置类:

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package com.test.spring.support.configuration;

@Configuration
public class TestConfiguration {
        public TestConfiguration(){
            System.out.println("spring容器启动初始化。。。");
        }

    //@Bean注解注册bean,同时可以指定初始化和销毁方法
    //@Bean(name="testNean",initMethod="start",destroyMethod="cleanUp")
    @Bean
    @Scope("prototype")
    public TestBean testBean() {
        return new TestBean();
    }
}
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主方法测试类:

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package com.test.spring.support.configuration;

public class TestMain {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(TestConfiguration.class);
        //获取bean
        TestBean tb = context.getBean("testBean");
        tb.sayHello();
    }
}
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注: 
(1)、@Bean注解在返回实例的方法上,如果未通过@Bean指定bean的名称,则默认与标注的方法名相同; 

(2)、@Bean注解默认作用域为单例singleton作用域,可通过@Scope(“prototype”)设置为原型作用域; 

(3)、既然@Bean的作用是注册bean对象,那么完全可以使用@Component、@Controller、@Service、@Ripository等注解注册bean,当然需要配置@ComponentScan注解进行自动扫描。

bean类:

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package com.test.spring.support.configuration;

//添加注册bean的注解
@Component
public class TestBean {

    public void sayHello(){
        System.out.println("TestBean sayHello...");
    }

    public String toString(){
        return "username:"+this.username+",url:"+this.url+",password:"+this.password;
    }
}
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配置类:

  • 技术分享
    @Configuration
    
    //添加自动扫描注解,basePackages为TestBean包路径
    @ComponentScan(basePackages = "com.test.spring.support.configuration")
    public class TestConfiguration {
        public TestConfiguration(){
            System.out.println("spring容器启动初始化。。。");
        }
    
        //取消@Bean注解注册bean的方式
        //@Bean
        //@Scope("prototype")
        //public TestBean testBean() {
        //  return new TestBean();
        //}
    }
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主方法测试获取bean对象:

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public class TestMain {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(TestConfiguration.class);
        //获取bean
        TestBean tb = context.getBean("testBean");
        tb.sayHello();
    }
}
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sayHello()方法都被正常调用。

 

(原文地址:http://www.cnblogs.com/ilinuxer/p/6503161.html)

[转]Spring注解-@Configuration注解、@Bean注解以及配置自动扫描、bean作用域

标签:ret   完全   location   ring   加载   sep   tostring   调用   文件中   

原文地址:http://www.cnblogs.com/jianyungsun/p/6680962.html

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