java-classic-code/spring-bean/SpringContextHelper.java

/*
 * Copyright 2009 by primedata Corporation.
 * ,
 *
 * All rights reserved.
 *
 * This software is the confidential and proprietary information of
 * primedata Corporation ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with primedata.
 */

package com.primeton.dgs.kernel.core.common;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;

/**
 * Spring上下文帮助类，方便获取bean、message等
 *
 * @author user
 * @version 1.0 Date: 2009-7-7
 */
@Slf4j
public class SpringContextHelper implements ApplicationContextAware {
	/**
	 * Spring上下文
	 */
	private static ApplicationContext applicationContext;

	/**
	 * 获取Spring上下文
	 *
	 * @return Spring Application Context
	 */
	public static ApplicationContext getSpringContext() {
		return applicationContext;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.springframework.context.ApplicationContextAware
	 * #setApplicationContext(org.springframework.context.ApplicationContext)
	 */
	public void setApplicationContext(ApplicationContext applicationContext)
			throws BeansException {
		SpringContextHelper.applicationContext = applicationContext;
	}

	/**
	 * 获取定义在Spring配置文件里的bean实例
	 *
	 * @param beanName Spring配置文件里的bean注册名
	 * @return bean实例（没有找到返回null）
	 */
	public static <T> T getBean(String beanName) {
		return (T) applicationContext.getBean(beanName);
	}

	/**
	 * 获取类型为requiredType的对象<br>
	 * 如果bean不能被类型转换，相应的异常将会被抛出（BeanNotOfRequiredTypeException）
	 *
	 * @param beanName     Spring配置文件里的bean注册名
	 * @param requiredType 返回对象类型
	 * @return bean实例（没有找到返回null）
	 */
	public static <T> T getBean(String beanName, Class<T> requiredType) throws BeansException {
		return applicationContext.getBean(beanName, requiredType);
	}

	public static <T> T getBean(Class<T> requiredType) throws BeansException {
		return applicationContext.getBean(requiredType);
	}

	public static <T> T getBean(String name, Object... args) throws BeansException {
		return (T) applicationContext.getBean(name, args);
	}

	public static <T> T getBean(Class<T> requiredType, Object... args) throws BeansException {
		return applicationContext.getBean(requiredType, args);
	}

	/**
	 * 如果BeanFactory包含一个与所给名称匹配的bean定义，则返回true
	 *
	 * @param name Spring配置文件里的bean注册名
	 * @return boolean
	 */
	public static boolean containsBean(String name) {
		return applicationContext.containsBean(name);
	}

	/**
	 * 判断以给定名字注册的bean定义是一个singleton还是一个prototype。
	 * 如果与给定名字相应的bean定义没有被找到，将会抛出一个异常（NoSuchBeanDefinitionException）
	 *
	 * @param name Spring配置文件里的bean注册名
	 * @return boolean 是否单例
	 * @throws NoSuchBeanDefinitionException 没有定义Bean
	 */
	public static boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
		return applicationContext.isSingleton(name);
	}

	/**
	 * 如果给定的bean名字在bean定义中有别名，则返回这些别名
	 *
	 * @param name Spring配置文件里的bean注册名
	 * @return 别名
	 * @throws NoSuchBeanDefinitionException 没有定义Bean
	 */
	public static String[] getAliases(String name) throws NoSuchBeanDefinitionException {
		return applicationContext.getAliases(name);
	}

	/**
	 * 手动注入Spring Bean中
	 *
	 * @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
	 */
	public static <T> T registerBean(String name, Class<T> clazz, Object... args) {
		ConfigurableApplicationContext context = null;
		if (applicationContext instanceof ConfigurableApplicationContext) {
			context = ((ConfigurableApplicationContext) applicationContext);
		}
		log.info("Register {} to spring context...",clazz.getCanonicalName());
		if (context != null) {
			if (context.containsBean(name)) {
				Object bean = context.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) context.getBeanFactory();
			beanFactory.registerBeanDefinition(name, beanDefinition);
			return context.getBean(name, clazz);
		}
		return null;
	}
}