Spring中使用两种Aware接口自定义获取bean
在使用spring编程时,常常会遇到想根据bean的名称来获取相应的bean对象,这时候,就可以通过实现BeanFactoryAware来满足需求,代码很简单:
@Service
public class BeanFactoryHelper implements BeanFactoryAware { private static BeanFactory beanFactory; @Override public void setBeanFactory(BeanFactory beanFactory) throws BeansException { this.beanFactory = beanFactory; } public static Object getBean(String beanName){
if(beanFactory == null){
throw new NullPointerException("BeanFactory is null!");
}
return beanFactory.getBean(beanName);
}
}
还有一种方式是实现ApplicationContextAware接口,代码也很简单:
@Service public class ApplicationContextHelper implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { this.applicationContext = applicationContext; } public static Object getBean(String beanName){ if(applicationContext == null){ throw new NullPointerException("ApplicationContext is null!"); } return applicationContext.getBean(beanName); } }
上面两种方法,只有容器启动的时候,才会把BeanFactory和ApplicationContext注入到自定义的helper类中,如果在本地junit测试的时候,如果需要根据bean的名称获取bean对象,则可以通过ClassPathXmlApplicationContext来获取一个ApplicationContext,代码如下:
@Test public void test() throws SQLException { //通过从classpath中加载spring-mybatis.xml实现bean的获取 ApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis.xml"); IUserService userService = (IUserService) context.getBean("userService"); User user = new User(); user.setName("test"); user.setAge(20); userService.addUser(user); }