spring：如何用代码动态向容器中添加北京PK10游戏制作或移除Bean ？

先来看一张北京PK10游戏制作【大神源码论坛】dsluntan.com  【布丁源码论坛】budingbbs.com 企娥3393756370类图：

有一个业务接口IFoo，提供了二个实现类：FooA及FooB，默认情况下，FooA使用@Component由Spring自动装配，如果出于某种原因，在运行时需要将IFoo的实现，则FooA换成FooB，可以用代码动态先将FooA的实例从容器中删除，然后再向容器中注入FooB的实例，代码如下：

1、IFoo接口：

package yjmyzz;

import org.springframework.beans.factory.DisposableBean; public interface IFoo extends DisposableBean { public void foo(); }

2、 FooA实现

package yjmyzz;


import org.springframework.stereotype.Component; //注：这里的名称fooA，仅仅只是为了后面演示时看得更清楚，非必需 @Component("fooA") public class FooA implements IFoo { public FooA() { System.out.println("FooA is created!"); } public void foo() { System.out.println("FooA.foo()"); } public void destroy() throws Exception { System.out.println("FooA.destroy()"); } }

3、FooB实现

package yjmyzz;


public class FooB implements IFoo { public FooB() { System.out.println("FooB is created!"); } public void foo() { System.out.println("FooB.foo()"); } public void destroy() throws Exception { System.out.println("FooB.destroy()"); } }

4、测试程序AppDemo

package yjmyzz;


import org.springframework.beans.factory.config.BeanDefinition; import org.springframework.beans.factory.support.BeanDefinitionBuilder; import org.springframework.beans.factory.support.BeanDefinitionRegistry; import org.springframework.beans.factory.support.DefaultListableBeanFactory; import org.springframework.context.support.AbstractRefreshableApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; /** * 演示在运行时，动态向容器中添加、移除Bean * author:菩提树下的杨过 http://yjmyzz.cnblogs.cm/ */ public class AppDemo { public static void main(String[] args) { ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml"); //从context中取出FooA实例 IFoo f = ctx.getBean(IFoo.class); f.foo();//FooA.foo() //输出IFoo的Bean基本信息 System.out.println(f.getClass());//class yjmyzz.FooA String beanName = ctx.getBeanNamesForType(IFoo.class)[0]; System.out.println(beanName);//fooA System.out.println(ctx.isSingleton(beanName));//true //销毁FooA实例 removeBean(ctx, beanName); System.out.println(ctx.containsBean(beanName));//false System.out.println("------------"); //注入新Bean beanName = "fooB"; addBean(ctx, beanName, FooB.class); //取出新实例 f = ctx.getBean(beanName, IFoo.class); f.foo(); //输出IFoo的Bean基本信息 System.out.println(f.getClass()); beanName = ctx.getBeanNamesForType(IFoo.class)[0]; System.out.println(beanName);//fooB System.out.println(ctx.isSingleton(beanName));//true System.out.println("------------"); showAllBeans(ctx); ctx.close(); } /** * 向容器中动态添加Bean * * @param ctx * @param beanName * @param beanClass */ static void addBean(AbstractRefreshableApplicationContext ctx, String beanName, Class beanClass) { BeanDefinitionRegistry beanDefReg = (DefaultListableBeanFactory) ctx.getBeanFactory(); BeanDefinitionBuilder beanDefBuilder = BeanDefinitionBuilder.genericBeanDefinition(beanClass); BeanDefinition beanDef = beanDefBuilder.getBeanDefinition(); if (!beanDefReg.containsBeanDefinition(beanName)) { beanDefReg.registerBeanDefinition(beanName, beanDef); } } /** * 从容器中移除Bean * * @param ctx * @param beanName */ static void removeBean(AbstractRefreshableApplicationContext ctx, String beanName) { BeanDefinitionRegistry beanDefReg = (DefaultListableBeanFactory) ctx.getBeanFactory(); beanDefReg.getBeanDefinition(beanName); beanDefReg.removeBeanDefinition(beanName); } /** * 遍历输出所有Bean的信息 */ static void showAllBeans(AbstractRefreshableApplicationContext ctx) { //遍历 for (String name : ctx.getBeanDefinitionNames()) { System.out.println("name:" + name + ",class:" + ctx.getBean(name).getClass()); } } }

beans.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:component-scan base-package="yjmyzz" /> </beans>

输出： FooA is created! FooA.foo() class yjmyzz.FooA fooA true FooA.destroy() false ------------ FooB is created! FooB.foo() class yjmyzz.FooB fooB true ------------ name:org.springframework.context.annotation.internalConfigurationAnnotationProcessor,class:class org.springframework.context.annotation.ConfigurationClassPostProcessor name:org.springframework.context.annotation.internalAutowiredAnnotationProcessor,class:class org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor name:org.springframework.context.annotation.internalRequiredAnnotationProcessor,class:class org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor name:org.springframework.context.annotation.internalCommonAnnotationProcessor,class:class org.springframework.context.annotation.CommonAnnotationBeanPostProcessor name:org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor,class:class org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor name:org.springframework.context.annotation.ConfigurationClassPostProcessor.enhancedConfigurationProcessor,class:class org.springframework.context.annotation.ConfigurationClassPostProcessor$EnhancedConfigurationBeanPostProcessor name:fooB,class:class yjmyzz.FooB FooB.destroy()