动态注入bean

系统管理员 2023-06-17 13:58 20阅读 0赞

/**
     * bean动态注入IOC容器
     */
    @Component
    public class BeanRegistry {
    
        private static final Logger logger = LoggerFactory.getLogger(BeanRegistry.class);
    
        @Autowired
        private SpringBeanTools springBeanTools;
    
        /**
         * 向Spring容器中注入bean(构造器注入)
         *
         * @param beanName        bean名称
         * @param beanClass       bean Class对象
         * @param constructorArgs 参数
         * @param <T>
         */
        public <T> void registerBean(String beanName, Class<T> beanClass, Object... constructorArgs) {
            if (null == beanClass) {
                if (logger.isDebugEnabled()) {
                   
                }
                return;
            }
    
            //构建BeanDefinitionBuilder
            BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(beanClass);
            for (Object obj : constructorArgs) {
                builder.addConstructorArgValue(obj);
            }
    
            //从builder中获取到BeanDefinition对象
            BeanDefinition beanDefinition = builder.getRawBeanDefinition();
    
            //获取spring容器中的IOC容器
            DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory) springBeanTools.getApplicationContext().getAutowireCapableBeanFactory();
    
            //向IOC容器中注入bean对象
            defaultListableBeanFactory.registerBeanDefinition(beanName, beanDefinition);
            //return defaultListableBeanFactory.getBean(beanName, beanClass);
        }
    
    }
    
    /**
     * 获取spring上下文
     * huangjq
     */
    @Component
    public class SpringBeanTools implements ApplicationContextAware {
    
        @Autowired
        private ApplicationContext applicationContext;
    
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            this.applicationContext = applicationContext;
        }
    
        /**
         * 获取指定的bean对象
         *
         * @param name  bean名称
         * @param clazz 类class对象
         * @param <T>
         * @return Bean对象
         */
        @SuppressWarnings("unchecked")
        public <T> T getBean(String name, Class<T> clazz) {
            //applicationContext非空
            Assert.isTrue((applicationContext != null), "应用上下文不能为空");
            Object bean = applicationContext.getBean(name);
            if (bean == null) {
                return null;
            }
            return (T)bean;
        }
    
        /**
         * 获取bean对象实例
         *
         * @param clazz 类class对象
         * @param <T>
         * @return Bean对象
         */
        public <T> T getBean(Class<T> clazz) {
            return applicationContext.getBean(clazz);
        }
    
        /**
         * 获取bean对象实例
         *
         * @param name 实例名称
         * @return
         */
        public Object getBean(String name) {
            return applicationContext.getBean(name);
        }
    
        /**
         * 获取 applicationContext 的值
         *
         * @return applicationContext
         */
        public ApplicationContext getApplicationContext() {
            return applicationContext;
        }
    
    }
    
    /**
     * bean 注入
     */
    public class ManualRegistBeanUtil {
    
        /**
        * 主动向Spring容器中注册bean
        *
        * @param applicationContext Spring容器
        * @param name               BeanName
        * @param clazz              注册的bean的类性
        * @param args               构造方法的必要参数，顺序和类型要求和clazz中定义的一致
        * @param <T>
        * @return 返回注册到容器中的bean对象
        */
       @SuppressWarnings("unchecked")
       public static <T> T registerBean(ConfigurableApplicationContext applicationContext, String name, Class<T> clazz, Object[] args) {
           if(applicationContext.containsBean(name)) {
               Object bean = applicationContext.getBean(name);
               if (bean.getClass().isAssignableFrom(clazz)) {
                   return (T) bean;
               } else {
                   throw new RuntimeException("BeanName 重复 " + name);
               }
           }
    
           BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
           for (Object arg : args) {
               beanDefinitionBuilder.addConstructorArgValue(arg);
           }
           BeanDefinition beanDefinition = beanDefinitionBuilder.getRawBeanDefinition();
    
           BeanDefinitionRegistry beanFactory = (BeanDefinitionRegistry) applicationContext.getBeanFactory();
           beanFactory.registerBeanDefinition(name, beanDefinition);
           return applicationContext.getBean(name, clazz);
       }
    }