spring4.0之二：@Configuration的使用
从Spring3.0，@Configuration用于定义配置类，可替换xml配置文件，被注解的类内部包含有一个或多个被@Bean注解的方法，这些方法将会被AnnotationConfigApplicationContext或AnnotationConfigWebApplicationContext类进行扫描，并用于构建bean定义，初始化Spring容器。
注意：@Configuration注解的配置类有如下要求：
- @Configuration不可以是final类型；
- @Configuration不可以是匿名类；
- 嵌套的configuration必须是静态类。
一、用@Configuration加载spring
1.1、@Configuration配置spring并启动spring容器
1.2、@Configuration启动容器+@Bean注册Bean
1.3、@Configuration启动容器+@Component注册Bean
1.4、使用 AnnotationConfigApplicationContext 注册 AppContext 类的两种方法
1.5、配置Web应用程序(web.xml中配置AnnotationConfigApplicationContext)
二、组合多个配置类
2.1、在@configuration中引入spring的xml配置文件
2.2、在@configuration中引入其它注解配置
2.3、@configuration嵌套（嵌套的Configuration必须是静态类）
三、@EnableXXX注解
四、@Profile逻辑组配置
五、使用外部变量
一、@Configuation加载Spring方法
1.1、@Configuration配置spring并启动spring容器
@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.dxz.demo.configuration;import org.springframework.context.annotation.Configuration;
@Configuration
public class TestConfiguration {
public TestConfiguration() {
System.out.println("TestConfiguration容器启动初始化。。。");
}
}
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>
主方法进行测试：
package com.dxz.demo.configuration;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TestMain {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(TestConfiguration.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果加载spring-context.xml文件： </span><span style="color: #008000;">//</span><span style="color: #008000;"> ApplicationContext context = new </span><span style="color: #008000;">//</span><span style="color: #008000;"> ClassPathXmlApplicationContext("spring-context.xml");</span>}
}
从运行主方法结果可以看出，spring容器已经启动了：
1.2、@Configuration启动容器+@Bean注册Bean，@Bean下管理bean的生命周期
@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.dxz.demo.configuration;public class TestBean {
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String username; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String url; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String password; </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> sayHello() { System.out.println(</span>"TestBean sayHello..."<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String toString() { </span><span style="color: #0000ff;">return</span> "username:" + <span style="color: #0000ff;">this</span>.username + ",url:" + <span style="color: #0000ff;">this</span>.url + ",password:" + <span style="color: #0000ff;">this</span><span style="color: #000000;">.password; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> start() { System.out.println(</span>"TestBean 初始化。。。"<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> cleanUp() { System.out.println(</span>"TestBean 销毁。。。"<span style="color: #000000;">); }}
配置类：
package com.dxz.demo.configuration;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;@Configuration
public class TestConfiguration {
public TestConfiguration() {
System.out.println("TestConfiguration容器启动初始化。。。");
}</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Bean注解注册bean,同时可以指定初始化和销毁方法 </span><span style="color: #008000;">//</span><span style="color: #008000;"> @Bean(name="testBean",initMethod="start",destroyMethod="cleanUp")</span>@Bean
@Scope("prototype")
public TestBean testBean() {
return new TestBean();
}
}
主方法测试类：
package com.dxz.demo.configuration;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TestMain {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(TestConfiguration.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果加载spring-context.xml文件： </span><span style="color: #008000;">//</span><span style="color: #008000;"> ApplicationContext context = new </span><span style="color: #008000;">//</span><span style="color: #008000;"> ClassPathXmlApplicationContext("spring-context.xml"); </span><span style="color: #008000;">//</span><span style="color: #008000;">获取bean</span> TestBean tb = (TestBean) context.getBean("testBean"<span style="color: #000000;">); tb.sayHello(); }}
结果：
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下管理bean的生命周期
可以使用基于 Java 的配置来管理 bean 的生命周期。@Bean 支持两种属性，即 initMethod 和destroyMethod，这些属性可用于定义生命周期方法。在实例化 bean 或即将销毁它时，容器便可调用生命周期方法。生命周期方法也称为回调方法，因为它将由容器调用。使用 @Bean 注释注册的 bean 也支持 JSR-250 规定的标准 @PostConstruct 和 @PreDestroy 注释。如果您正在使用 XML 方法来定义 bean，那么就应该使用 bean 元素来定义生命周期回调方法。以下代码显示了在 XML 配置中通常使用 bean 元素定义回调的方法。
@Configuration @ComponentScan(basePackages = "com.dxz.demo.configuration") public class TestConfiguration { public TestConfiguration() { System.out.println("TestConfiguration容器启动初始化。。。"); }</span><span style="color: #008000;">//</span><span style="color: #008000;">@Bean注解注册bean,同时可以指定初始化和销毁方法</span> <span style="background-color: #ff6600; color: #ffffff;">@Bean(name="testBean",initMethod="start",destroyMethod="cleanUp") @Scope("prototype") </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> TestBean testBean() { </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span><span style="color: #000000;"> TestBean(); }}
启动类：
public class TestMain { public static void main(String[] args) {ApplicationContext context </span>= <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(TestConfiguration.<span style="color: #0000ff;">class</span><span style="color: #000000;">); TestBean tb </span>= (TestBean) context.getBean("testBean"<span style="color: #000000;">); tb.sayHello(); System.out.println(tb); TestBean tb2 </span>= (TestBean) context.getBean("testBean"<span style="color: #000000;">); tb2.sayHello(); System.out.println(tb2); }}
结果：
分析：
结果中的1：表明initMethod生效
结果中的2：表明@Scope("prototype")生效
1.3、@Configuration启动容器+@Component注册Bean
bean类：
package com.dxz.demo.configuration;import org.springframework.stereotype.Component;
//添加注册bean的注解
@Component
public class TestBean {</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String username; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String url; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String password; </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> sayHello() { System.out.println(</span>"TestBean sayHello..."<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String toString() { </span><span style="color: #0000ff;">return</span> "username:" + <span style="color: #0000ff;">this</span>.username + ",url:" + <span style="color: #0000ff;">this</span>.url + ",password:" + <span style="color: #0000ff;">this</span><span style="color: #000000;">.password; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> start() { System.out.println(</span>"TestBean 初始化。。。"<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> cleanUp() { System.out.println(</span>"TestBean 销毁。。。"<span style="color: #000000;">); }}
配置类：
package com.dxz.demo.configuration;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;@Configuration
//添加自动扫描注解，basePackages为TestBean包路径
@ComponentScan(basePackages = "com.dxz.demo.configuration")
public class TestConfiguration {
public TestConfiguration() {
System.out.println("TestConfiguration容器启动初始化。。。");
}</span><span style="color: #008000;">/*</span><span style="color: #008000;">// @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(); }</span><span style="color: #008000;">*/</span><span style="color: #000000;">}
主方法测试获取bean对象：
package com.dxz.demo.configuration;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TestMain {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(TestConfiguration.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果加载spring-context.xml文件： </span><span style="color: #008000;">//</span><span style="color: #008000;"> ApplicationContext context = new </span><span style="color: #008000;">//</span><span style="color: #008000;"> ClassPathXmlApplicationContext("spring-context.xml"); </span><span style="color: #008000;">//</span><span style="color: #008000;">获取bean</span> TestBean tb = (TestBean) context.getBean("testBean"<span style="color: #000000;">); tb.sayHello(); }}
sayHello()方法都被正常调用。
1.4、使用 AnnotationConfigApplicationContext 注册 AppContext 类的两种方法
1.4.1、 配置类的注册方式是将其传递给 AnnotationConfigApplicationContext 构造函数
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> <span style="background-color: #ff6600; color: #ffffff;">ApplicationContext context = new AnnotationConfigApplicationContext(TestConfiguration.class);//获取bean
TestBean tb = (TestBean) context.getBean("testBean");
tb.sayHello();
}
1.4.2、 AnnotationConfigApplicationContext 的register 方法传入配置类来注册配置类
public static void main(String[] args) { ApplicationContext ctx = new AnnotationConfigApplicationContext(); ctx.register(AppContext.class) }
1.5、配置Web应用程序(web.xml中配置AnnotationConfigApplicationContext)
过去，您通常要利用 XmlWebApplicationContext 上下文来配置 Spring Web 应用程序，即在 Web 部署描述符文件 web.xml 中指定外部 XML 上下文文件的路径。XMLWebApplicationContext 是 Web 应用程序使用的默认上下文类。以下代码描述了 web.xml 中指向将由 ContextLoaderListener 监听器类载入的外部 XML 上下文文件的元素。
<web-app> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <servlet> <servlet-name>sampleServlet</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> </servlet>...
</web-app>
现在，您要将 web.xml 中的上述代码更改为使用 AnnotationConfigApplicationContext 类。切记，XmlWebApplicationContext 是 Spring 为 Web 应用程序使用的默认上下文实现，因此您永远不必在您的web.xml 文件中显式指定这个上下文类。现在，您将使用基于 Java 的配置，因此在配置 Web 应用程序时，需要在web.xml 文件中指定 AnnotationConfigApplicationContext 类。上述代码将修改如下：
<web-app> <context-param> <param-name>contextClass</param-name> <param-value> org.springframework.web.context. support.AnnotationConfigWebApplicationContext </param-value> </context-param> <context-param> <param-name>contextConfigLocation</param-name> <param-value> demo.AppContext </param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <servlet> <servlet-name>sampleServlet</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>contextClass</param-name> <param-value> org.springframework.web.context. support.AnnotationConfigWebApplicationContext </param-value> </init-param> </servlet>...
</web-app>
以上修改后的 web.xml 现在定义了 AnnotationConfigWebApplicationContext 上下文类，并将其作为上下文参数和 servlet 元素的一部分。上下文配置位置现在指向 AppContext 配置类。这非常简单。下一节将演示 bean 的生命周期回调和范围的实现。
1.6、@Configuation总结
@Configuation等价于<Beans></Beans>
@Bean等价于<Bean></Bean>
@ComponentScan等价于<context:component-scan base-package="com.dxz.demo"/>
二、组合多个配置类
2.1、在@configuration中引入spring的xml配置文件
package com.dxz.demo.configuration2;import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;@Configuration
@ImportResource("classpath:applicationContext-configuration.xml")
public class WebConfig {
}
bean类：
package com.dxz.demo.configuration2;public class TestBean2 {
private String username;
private String url;
private String password;</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> sayHello() { System.out.println(</span>"TestBean2 sayHello..."<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String toString() { </span><span style="color: #0000ff;">return</span> "TestBean2 username:" + <span style="color: #0000ff;">this</span>.username + ",url:" + <span style="color: #0000ff;">this</span>.url + ",password:" + <span style="color: #0000ff;">this</span><span style="color: #000000;">.password; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> start() { System.out.println(</span>"TestBean2 初始化。。。"<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> cleanUp() { System.out.println(</span>"TestBean2 销毁。。。"<span style="color: #000000;">); }}
测试类：
package com.dxz.demo.configuration2;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TestMain2 {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(WebConfig.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果加载spring-context.xml文件： </span><span style="color: #008000;">//</span><span style="color: #008000;"> ApplicationContext context = new </span><span style="color: #008000;">//</span><span style="color: #008000;"> ClassPathXmlApplicationContext("spring-context.xml"); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 获取bean</span> TestBean2 tb = (TestBean2) context.getBean("testBean2"<span style="color: #000000;">); tb.sayHello(); }}
结果：
2.2、在@configuration中引入其它注解配置
package com.dxz.demo.configuration2;import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.ImportResource;import com.dxz.demo.configuration.TestConfiguration;
@Configuration
@ImportResource("classpath:applicationContext-configuration.xml")
@Import(TestConfiguration.class)
public class WebConfig {
}
测试类：
package com.dxz.demo.configuration2;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;import com.dxz.demo.configuration.TestBean;
public class TestMain2 {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContext</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(WebConfig.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果加载spring-context.xml文件： </span><span style="color: #008000;">//</span><span style="color: #008000;"> ApplicationContext context = new </span><span style="color: #008000;">//</span><span style="color: #008000;"> ClassPathXmlApplicationContext("spring-context.xml"); </span><span style="color: #008000;">//</span><span style="color: #008000;"> 获取bean</span> TestBean2 tb2 = (TestBean2) context.getBean("testBean2"<span style="color: #000000;">); tb2.sayHello(); <span style="color: #ff0000;">TestBean tb </span></span><span style="color: #ff0000;">= (TestBean) context.getBean("testBean"</span><span style="color: #000000;"><span style="color: #ff0000;">); tb.sayHello();</span> }}
结果：
2.3、@configuration嵌套（嵌套的Configuration必须是静态类）
通过配置类嵌套的配置类，达到组合多个配置类的目的。但注意内部类必须是静态类。
上代码：
package com.dxz.demo.configuration3;import org.springframework.stereotype.Component;
@Component
public class TestBean {</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String username; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String url; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String password; </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> sayHello() { System.out.println(</span>"TestBean sayHello..."<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String toString() { </span><span style="color: #0000ff;">return</span> "username:" + <span style="color: #0000ff;">this</span>.username + ",url:" + <span style="color: #0000ff;">this</span>.url + ",password:" + <span style="color: #0000ff;">this</span><span style="color: #000000;">.password; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> start() { System.out.println(</span>"TestBean start"<span style="color: #000000;">); } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> cleanUp() { System.out.println(</span>"TestBean destory"<span style="color: #000000;">); }}
package com.dxz.demo.configuration3;public class DataSource {
</span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String dbUser; </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> String dbPass; </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String getDbUser() { </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> dbUser; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setDbUser(String dbUser) { </span><span style="color: #0000ff;">this</span>.dbUser =<span style="color: #000000;"> dbUser; } </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String getDbPass() { </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> dbPass; } </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> setDbPass(String dbPass) { </span><span style="color: #0000ff;">this</span>.dbPass =<span style="color: #000000;"> dbPass; } @Override </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> String toString() { </span><span style="color: #0000ff;">return</span> "DataSource [dbUser=" + dbUser + ", dbPass=" + dbPass + "]"<span style="color: #000000;">; }}
配置类：
package com.dxz.demo.configuration3;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;@Configuration
@ComponentScan(basePackages = "com.dxz.demo.configuration3")
public class TestConfiguration {
public TestConfiguration() {
System.out.println("TestConfiguration容器启动初始化。。。");
}@Configuration
static class DatabaseConfig {
@Bean
DataSource dataSource() {
return new DataSource();
}
}
}
启动类：
package com.dxz.demo.configuration3;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class TestMain {
public static void main(String[] args) {</span><span style="color: #008000;">//</span><span style="color: #008000;"> @Configuration注解的spring容器加载方式，用AnnotationConfigApplicationContext替换ClassPathXmlApplicationContexts</span> ApplicationContext context = <span style="color: #0000ff;">new</span> AnnotationConfigApplicationContext(TestConfiguration.<span style="color: #0000ff;">class</span><span style="color: #000000;">); </span><span style="color: #008000;">//</span><span style="color: #008000;">bean</span> TestBean tb = (TestBean) context.getBean("testBean"<span style="color: #000000;">); tb.sayHello(); DataSource ds </span>= (DataSource) context.getBean("dataSource"<span style="color: #000000;">); System.out.println(ds); }}
结果：
TestConfiguration容器启动初始化。。。 TestBean sayHello... DataSource [dbUser=null, dbPass=null]
3、@EnableXXX注解
配合@Configuration使用，包括 @EnableAsync, @EnableScheduling, @EnableTransactionManagement, @EnableAspectJAutoProxy, @EnableWebMvc。
@EnableAspectJAutoProxy---《spring AOP 之：@Aspect注解》
@EnableScheduling--《Spring 3.1新特性之二：@Enable*注解的源码,spring源码分析之定时任务Scheduled注解》
4、@Profile逻辑组配置
5、使用外部变量
1、@PropertySource + Environment，通过@PropertySource注解将properties配置文件中的值存储到Spring的 Environment中，Environment接口提供方法去读取配置文件中的值，参数是properties文件中定义的key值。
2、@PropertySource（PropertySourcesPlaceholderConfigurer）+@Value
原文地址：https://www.cnblogs.com/duanxz/p/7493276.html
