Spring中动态注册和销毁对象

1. 使用说明

通常我们项目中想要往spring容器中注入一个bean可以在项目初始化的时候结合@Bean注解实现。但是该方法适合项目初始化时候使用，如果后续想要继续注入对象则无可奈何。本文主要描述一种在后续往spring容器注入bean的方法。

2. 实现

2.1 说明

2.1.1 注册bean

定义BeanDefinition，注册类定义到factory中
创建对象，注册实例到fatory中

2.1.2 销毁bean

判断是否有类定义。有，则移除BeanDefinition
判断是否有对象。有，则从容器中去除

2.2 代码

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;import javax.annotation.PostConstruct;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;/*** @author pp_lan* @date 2024/1/17*/
@Component
public class SpringUtils {@Autowiredprivate ApplicationContext context;private DefaultListableBeanFactory factory;@PostConstructpublic void init() {factory = (DefaultListableBeanFactory) context.getAutowireCapableBeanFactory();}/*** 注册对象** @param beanName* @param object*/public void registerBean(String beanName, Object object) {// 添加类定义factory.registerBeanDefinition(beanName, new RootBeanDefinition(object.getClass()));// 添加类实例factory.registerSingleton(beanName, object);}/*** 删除对象** @param beanName*/public void removeBean(String beanName) {List<String> beanDefinitionList = Arrays.asList(factory.getBeanDefinitionNames());if (beanDefinitionList.contains(beanName)) {factory.destroySingleton(beanName);}for (Iterator<String> it = factory.getBeanNamesIterator();it.hasNext();) {String next = it.next();if (next.equals(beanName)) {factory.removeBeanDefinition(beanName);return;}}}/*** 获取bean** @param clazz* @return* @param <T>*/public <T> T getBean(String name, Class<T> clazz) {for(Iterator<String> it = factory.getBeanNamesIterator();it.hasNext();) {String next = it.next();if (next.equals(name)) {return this.context.getBean(name, clazz);}}return null;}
}

2.3 测试代码

 @RequestMapping("/addUser")public Response add(String userId) {User user = new User(userId, "zhang", "小张");springUtils.removeBean("user");springUtils.registerBean("user", user);User zhang = springUtils.getBean("user", User.class);return Response.ok(zhang);}@RequestMapping("/get")public Response get() {return Response.ok(springUtils.getBean("user", User.class));}