如何动态往Spring容器注册/移除bean？

几个关键点需要知道

本文不谈原理，直接上实战。

几个关键点：如何拿到Spring上下文来创建bean或移除bean？如何准备构建bean所需的BeanDefinition？

第一问：可注入bean工厂org.springframework.beans.factory.support.DefaultListableBeanFactory得到；

第二问：使用org.springframework.beans.factory.support.BeanDefinitionBuilder来构建BeanDefinition。

实例

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.stereotype.Component;import java.beans.Introspector;
import java.lang.reflect.Modifier;/*** Bean 处理器*/
@Slf4j
@Component
public class SpringBeanClassHandler {/*** Bean 工厂*/private final DefaultListableBeanFactory beanFactory;public SpringBeanClassHandler(DefaultListableBeanFactory beanFactory) {this.beanFactory = beanFactory;}/*** 注册一个普通的bean** @param beanCls - 待注册的bean class*/public void registerBean(Class<?> beanCls) {if (beanCls == null) {return;}if (Modifier.isAbstract(beanCls.getModifiers())|| Modifier.isPrivate(beanCls.getModifiers())|| Modifier.isNative(beanCls.getModifiers())|| Modifier.isInterface(beanCls.getModifiers())) {log.warn("can not support register this class to bean for: {} - {}", beanCls.getName(), Modifier.toString(beanCls.getModifiers()));}// 注册新的BeanString beanName = Introspector.decapitalize(beanCls.getSimpleName());BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(beanCls);GenericBeanDefinition definition = (GenericBeanDefinition) builder.getRawBeanDefinition();definition.setAutowireMode(GenericBeanDefinition.AUTOWIRE_BY_TYPE);// 按类型自动注入beanFactory.registerBeanDefinition(beanName, definition);log.info("dynamic successfully register bean: {}", beanFactory.getBean(beanName));}/*** 移除 Bean** @param beanCls - Bean class*/public void removeBean(Class<?> beanCls) {if (beanCls == null) {return;}String clsName = Introspector.decapitalize(beanCls.getSimpleName());if (beanFactory.containsBean(clsName)) {beanFactory.removeBeanDefinition(clsName);}}/*** Spring 容器是否 已存在Bean** @param beanCls* @return - boolean*/public boolean containsBean(Class<?> beanCls) {return beanFactory.containsBean(Introspector.decapitalize(beanCls.getSimpleName()));}
}

完结。