Spring实现Aware接口自定义获取bean的两种方式
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:
@ServicepublicclassBeanFactoryHelperimplementsBeanFactoryAware{
privatestaticBeanFactorybeanFactory;
@Override
publicvoidsetBeanFactory(BeanFactorybeanFactory)throwsBeansException{
this.beanFactory=beanFactory;
}
publicstaticObjectgetBean(StringbeanName){
if(beanFactory==null){
thrownewNullPointerException("BeanFactoryisnull!");
}
returnbeanFactory.getBean(beanName);}}
还有一种方式是实现ApplicationContextAware接口,代码也很简单:
@Service
publicclassApplicationContextHelperimplementsApplicationContextAware{
privatestaticApplicationContextapplicationContext;
@Override
publicvoidsetApplicationContext(ApplicationContextapplicationContext)throwsBeansException{
this.applicationContext=applicationContext;
}
publicstaticObjectgetBean(StringbeanName){
if(applicationContext==null){
thrownewNullPointerException("ApplicationContextisnull!");
}
returnapplicationContext.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
publicvoidtest()throwsSQLException{
//通过从classpath中加载spring-mybatis.xml实现bean的获取
ApplicationContextcontext=newClassPathXmlApplicationContext("spring-mybatis.xml");
IUserServiceuserService=(IUserService)context.getBean("userService");
Useruser=newUser();
user.setName("test");
user.setAge(20);
userService.addUser(user);
}
总结
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