Spring获取bean对象常见的几种方式

1、常用的是使用@Autowired注解

点击查看代码

@Autowired
private UserService userService;

2、实现BeanFactoryAware，重写setBeanFactory方法

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@Service
public class GetBean1 implements BeanFactoryAware {

    private BeanFactory beanFactory;

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = beanFactory;
    }

    public <T> T getBean(Class<T> type){
        return beanFactory.getBean(type);
    }
}

3、继承ApplicationObjectSupport，获取ApplicationContext对象

点击查看代码

@Service
public class GetBean2 extends ApplicationObjectSupport {

    public <T> T getBean(Class<T> type){
        ApplicationContext applicationContext = getApplicationContext();
        return applicationContext.getBean(type);
    }
}

4、实现ApplicationContextAware，重写setApplicationContext

点击查看代码

@Service
public class GetBean3 implements ApplicationContextAware {

    private ApplicationContext applicationContext;

    public <T> T getBean(Class<T> type){
        return applicationContext.getBean(type);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }
}

5、实现BeanFactoryPostProcessor，重写postProcessBeanFactory

点击查看代码

@Service
public class GetBean4 implements BeanFactoryPostProcessor {

    private ConfigurableListableBeanFactory configurableListableBeanFactory;

    public <T> T getBean(Class<T> type){
        return configurableListableBeanFactory.getBean(type);
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
        this.configurableListableBeanFactory = configurableListableBeanFactory;
    }
}