普通类获取Spring容器中的Bean

方式一

@Component
public class SpringApplicationContextHolder implements ApplicationContextAware {
	private static ApplicationContext applicationContext;

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

	/**
	 * 获取applicationContext对象
	 * 
	 * @return
	 */
	public static ApplicationContext getApplicationContext() {
		return applicationContext;
	}

	/**
	 * 根据beanid获取spring中的bean对象
	 * 
	 * @param beanId
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public static <T> T getBean(String beanId) {
		return (T) applicationContext.getBean(beanId);
	}

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

方式二

@Component
public final class SpringUtils implements BeanFactoryPostProcessor {
    /**
     * Spring应用上下文环境
     */
    private static ConfigurableListableBeanFactory beanFactory;

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        SpringUtils.beanFactory = beanFactory;
    }

    /**
     * 获取对象
     *
     * @param name
     * @return Object 一个以所给名字注册的bean的实例
     * @throws org.springframework.beans.BeansException
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) throws BeansException {
        return (T) beanFactory.getBean(name);
    }

    /**
     * 获取类型为requiredType的对象
     *
     * @param clz
     * @return
     * @throws org.springframework.beans.BeansException
     */
    public static <T> T getBean(Class<T> clz) throws BeansException {
        T result = beanFactory.getBean(clz);
        return result;
    }
}

注意不要忘了加@Component或xml方式配置

两种方式使用哪个好呢

通过对比ApplicationContextAware和BeanFactoryPostProcessor文档发现

使用ApplicationContextAware更好

因为BeanFactoryPostProcessor获取的是ConfigurableListableBeanFactory允许修改配置的属性，影响安全

ApplicationContextAware是获取ApplicationContext，对它有种亲切感

/**
 * Allows for custom modification of an application context's bean definitions
 */
@FunctionalInterface
public interface BeanFactoryPostProcessor

**
 * Interface to be implemented by any object that wishes to be notified
 * of the {@link ApplicationContext} that it runs in.
 */
 public interface ApplicationContextAware extends Aware