Spring.jpg

前言

从Spring3.0开始，@Configuration用于定义配置类，可以替换Spring的xml配置文件，常常配合@Bean使用，一个@Configuration注解的类中可以有一个或多个@Bean注解的方法

---

详细使用方法

1. 单独使用@Configuration注解在类上

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

这种相当于加载了一个spring配置文件，<beans></beans>标签你没有配置任何一个<bean></bean>相当于下面这样的Spring的xml配置文件

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="[http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans)" xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"

    xmlns:context="[http://www.springframework.org/schema/context](http://www.springframework.org/schema/context)" xmlns:jdbc="[http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc)" 

    xmlns:jee="[http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee)" xmlns:tx="[http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx)"

    xmlns:util="[http://www.springframework.org/schema/util](http://www.springframework.org/schema/util)" xmlns:task="[http://www.springframework.org/schema/task](http://www.springframework.org/schema/task)" xsi:schemaLocation="

        [http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans) [http://www.springframework.org/schema/beans/spring-beans-4.0.xsd](http://www.springframework.org/schema/beans/spring-beans-4.0.xsd)

        [http://www.springframework.org/schema/context](http://www.springframework.org/schema/context) [http://www.springframework.org/schema/context/spring-context-4.0.xsd](http://www.springframework.org/schema/context/spring-context-4.0.xsd)

        [http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc) [http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd](http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd)

        [http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee) [http://www.springframework.org/schema/jee/spring-jee-4.0.xsd](http://www.springframework.org/schema/jee/spring-jee-4.0.xsd)

        [http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx) [http://www.springframework.org/schema/tx/spring-tx-4.0.xsd](http://www.springframework.org/schema/tx/spring-tx-4.0.xsd)

        [http://www.springframework.org/schema/util](http://www.springframework.org/schema/util) [http://www.springframework.org/schema/util/spring-util-4.0.xsd](http://www.springframework.org/schema/util/spring-util-4.0.xsd)

        [http://www.springframework.org/schema/task](http://www.springframework.org/schema/task) [http://www.springframework.org/schema/task/spring-task-4.0.xsd](http://www.springframework.org/schema/task/spring-task-4.0.xsd)" default-lazy-init="false">

</beans>

2. @Configuration注解类+@Bean注解方法

@Configuration
public class TestConfiguration {
    public TestConfiguration() {
        System.out.println("TestConfiguration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="testBean",initMethod="start",destroyMethod="cleanUp")
    @Bean
    @Scope("prototype")
    public TestBean testBean() {
        return new TestBean();
    }
}

这等同于在<beans></beans>标签中配置一个<bean id="testBean" class="TestBean"></bean>，并且可以在@Bean中指定实例的初始化方法和销毁方法，等效于下面的Spring的xml配置文件

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="[http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans)" xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"

    xmlns:context="[http://www.springframework.org/schema/context](http://www.springframework.org/schema/context)" xmlns:jdbc="[http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc)" 

    xmlns:jee="[http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee)" xmlns:tx="[http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx)"

    xmlns:util="[http://www.springframework.org/schema/util](http://www.springframework.org/schema/util)" xmlns:task="[http://www.springframework.org/schema/task](http://www.springframework.org/schema/task)" xsi:schemaLocation="

        [http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans) [http://www.springframework.org/schema/beans/spring-beans-4.0.xsd](http://www.springframework.org/schema/beans/spring-beans-4.0.xsd)

        [http://www.springframework.org/schema/context](http://www.springframework.org/schema/context) [http://www.springframework.org/schema/context/spring-context-4.0.xsd](http://www.springframework.org/schema/context/spring-context-4.0.xsd)

        [http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc) [http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd](http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd)

        [http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee) [http://www.springframework.org/schema/jee/spring-jee-4.0.xsd](http://www.springframework.org/schema/jee/spring-jee-4.0.xsd)

        [http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx) [http://www.springframework.org/schema/tx/spring-tx-4.0.xsd](http://www.springframework.org/schema/tx/spring-tx-4.0.xsd)

        [http://www.springframework.org/schema/util](http://www.springframework.org/schema/util) [http://www.springframework.org/schema/util/spring-util-4.0.xsd](http://www.springframework.org/schema/util/spring-util-4.0.xsd)

        [http://www.springframework.org/schema/task](http://www.springframework.org/schema/task) [http://www.springframework.org/schema/task/spring-task-4.0.xsd](http://www.springframework.org/schema/task/spring-task-4.0.xsd)" default-lazy-init="false”>

<bean id="testBean" class="TestBean"></bean>

</beans>

3. @Configuration注解类+ @ComponentScan注解类

@Configuration
//添加自动扫描注解，basePackages为TestBean包路径
@ComponentScan(basePackages = "com.xxx.demo.configuration")
public class TestConfiguration {
    public TestConfiguration() {
        System.out.println("TestConfiguration容器启动初始化。。。");
    }
}

@ComponentScan用于配置自动扫描包，等效于下面的Spring的xml配置文件

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="[http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans)" xmlns:xsi="[http://www.w3.org/2001/XMLSchema-instance](http://www.w3.org/2001/XMLSchema-instance)"

    xmlns:context="[http://www.springframework.org/schema/context](http://www.springframework.org/schema/context)" xmlns:jdbc="[http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc)" 

    xmlns:jee="[http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee)" xmlns:tx="[http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx)"

    xmlns:util="[http://www.springframework.org/schema/util](http://www.springframework.org/schema/util)" xmlns:task="[http://www.springframework.org/schema/task](http://www.springframework.org/schema/task)" xsi:schemaLocation="

        [http://www.springframework.org/schema/beans](http://www.springframework.org/schema/beans) [http://www.springframework.org/schema/beans/spring-beans-4.0.xsd](http://www.springframework.org/schema/beans/spring-beans-4.0.xsd)

        [http://www.springframework.org/schema/context](http://www.springframework.org/schema/context) [http://www.springframework.org/schema/context/spring-context-4.0.xsd](http://www.springframework.org/schema/context/spring-context-4.0.xsd)

        [http://www.springframework.org/schema/jdbc](http://www.springframework.org/schema/jdbc) [http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd](http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.xsd)

        [http://www.springframework.org/schema/jee](http://www.springframework.org/schema/jee) [http://www.springframework.org/schema/jee/spring-jee-4.0.xsd](http://www.springframework.org/schema/jee/spring-jee-4.0.xsd)

        [http://www.springframework.org/schema/tx](http://www.springframework.org/schema/tx) [http://www.springframework.org/schema/tx/spring-tx-4.0.xsd](http://www.springframework.org/schema/tx/spring-tx-4.0.xsd)

        [http://www.springframework.org/schema/util](http://www.springframework.org/schema/util) [http://www.springframework.org/schema/util/spring-util-4.0.xsd](http://www.springframework.org/schema/util/spring-util-4.0.xsd)

        [http://www.springframework.org/schema/task](http://www.springframework.org/schema/task) [http://www.springframework.org/schema/task/spring-task-4.0.xsd](http://www.springframework.org/schema/task/spring-task-4.0.xsd)" default-lazy-init="false”>

<context:component-scan base-package="com.xxx.demo"/>

</beans>

4. 使用@Import引入其他配置类

@Configuration
@ImportResource("classpath:applicationContext-configuration.xml")
@Import(TestConfiguration.class)
public class WebConfig {
}

通过上面这种方式可以在一个配置类中引入其他配置类或者配置文件

---

总结

简单介绍了几个配置类中常用注解的使用方法

• 单独使用@Configuration注解在类上
• @Configuration注解类+@Bean注解方法
• @Configuration注解类+ @ComponentScan注解类
• 使用@Import引入其他配置类