SpringBoot运行时动态注册Bean到IOC容器中

大概思路

通过实现 ApplicationContextAware接口，通过Spring启动过程中回调setApplicationContext接口，获取spring的IOC容器，然后就可以注册bean到Spring容器中了。

编码实现

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;

/**
 * @author yuwenbo1
 * @since 2021/3/25 9:57
 */
@Slf4j
@Component
public class SpringContainerExtend implements ApplicationContextAware {

    private DefaultListableBeanFactory defaultListableBeanFactory;

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        log.info("get applicationContext");
        this.applicationContext = applicationContext;
        //将applicationContext转换为ConfigurableApplicationContext
        ConfigurableApplicationContext configurableApplicationContext = (ConfigurableApplicationContext) applicationContext;
        // 获取bean工厂并转换为DefaultListableBeanFactory
        this.defaultListableBeanFactory = (DefaultListableBeanFactory) configurableApplicationContext.getBeanFactory();
        log.info("get BeanFactory Success.");
    }

    /**
     * 注册bean到spring容器中
     *
     * @param beanName 名称
     * @param clazz    class
     */
    public void registerBean(String beanName, Class<?> clazz) {
        // 通过BeanDefinitionBuilder创建bean定义
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
        // 尝试移除之前相同的bean
        if (defaultListableBeanFactory.containsBean(beanName)) {
            defaultListableBeanFactory.removeBeanDefinition(beanName);
        }
        // 注册bean
        defaultListableBeanFactory
                .registerBeanDefinition(beanName, beanDefinitionBuilder.getRawBeanDefinition());
        log.info("register bean [{}],Class [{}] success.", beanName, clazz);
    }

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

    public Object getBean(String name) {
        return applicationContext.getBean(name);
    }
}