Use @configuration annotations instead of Spring bean configuration

The following is a typical spring configuration file (application-config.xml):

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<beans>         <beanid="orderService" class="com.acme.OrderService"/>                 <constructor-argref="orderRepository"/>         </bean>         <beanid="orderRepository" class="com.acme.OrderRepository"/>                 <constructor-arg ref="dataSource"/>         </bean> </beans>

Then you can use a bean like this:

12	ApplicationContext ctx = newClassPathXmlApplicationContext("application-config.xml"); OrderService orderService = (OrderService) ctx.getBean("orderService");

Now spring Java Configuration This project provides a scheme to assemble beans through Java code:

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@Configurationpublicclass ApplicationConfig {           public@BeanOrderService orderService() {                 returnnewOrderService(orderRepository());         }           public@BeanOrderRepository orderRepository() {                 returnnewOrderRepository(dataSource());         }            public@BeanDataSource dataSource() {                 // instantiate and return an new DataSource …         } }

Then you can use a bean like this:

12	JavaConfigApplicationContext ctx = newJavaConfigApplicationContext(ApplicationConfig.class); OrderService orderService = ctx.getBean(OrderService.class);

　　

What's the good of doing this?

1. Use plain Java code and do not need XML

2. The benefits of OO can also be enjoyed in the configuration

3. Type safety can also provide good support for refactoring

4. Can still enjoy all the functions provided by the SPRINGIOC container

Category: Spring

Use @configuration annotations instead of Spring bean configuration