Spring整理系列(11)——@Configuration注解、@Bean注解以及配置自动扫描、bean作用域 发表于2016811 15:16:1610628人阅读 分类： Spring

来源 http://m.blog.csdn.net/javaloveiphone/article/details/52182899

发表于2016/8/11 15:16:16  10628人阅读

分类： Spring

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)

package com.test.spring.support.configuration; @Configuration public class TestConfiguration { public TestConfiguration(){ System.out.println("spring容器启动初始化。。。"); } } 12345678

相当于：

<?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> 123456789101112131415

主方法进行测试：

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"); } } 123456789101112

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。。。 123

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：

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。。。"); } } 1234567891011121314151617181920

配置类：

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(); } } 12345678910111213141516

主方法测试类：

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(); } } 12345678910

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：

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; } } 1234567891011121314

配置类：

@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(); //} } 12345678910111213141516

主方法测试获取bean对象：

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(); } } 12345678

sayHello()方法都被正常调用。