springboot 通过类名称获取bean

IOC容器有beanFactory 和ApplicationContext.通常建议使用后者，因为它包含了前者的功能。Spring的核心是ApplicationContext.它负责管理 beans 的完整生命周期。我们可以从applicationContext里通过bean名称获取安装的bean.进行某种操作。不能直接使用applicationContext.而需要借助applicationContextAware.具体方法如下：

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

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

    public static Object getBean(String className) throws BeansException,IllegalArgumentException {
        if(className==null || className.length()<=0) {
            throw new IllegalArgumentException("className为空");
        }

        String beanName = null;
        if(className.length() > 1) {
            beanName = className.substring(0, 1).toLowerCase() + className.substring(1);
        } else {
            beanName = className.toLowerCase();
        }
        return applicationContext != null ? applicationContext.getBean(beanName) : null;
    }

}

声明一个ApplicationContextHelper组件，名字随意。它实现了ApplicationContextAware接口。并重写setApplicationContext方法。在该组件里可以通过名字获取某个bean.

使用

@Slf4j
@RestController
@RequestMapping("/getbean")
public class GetBeanTestController {

    @GetMapping("/retryService")
    public String retryService(@RequestParam int num){

        RetryService retryService = (RetryService) ApplicationContextGetBeanHelper.getBean("RetryService");
        String ss = retryService.print();

        return ss;
    }

}