先來看一張類圖：

有一個業務接口IFoo，提供了二個實現類：FooA及FooB，默認情況下，FooA使用@Component由Spring自動裝配，如果出于某種原因，在運行時需要將IFoo的實現，則FooA換成FooB，可以用代碼動態先將FooA的實例從容器中刪除，然后再向容器中注入FooB的實例，代碼如下：

1、IFoo接口：

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

2、 FooA實現

package yjmyzz;import org.springframework.stereotype.Component;//注：這里的名稱fooA，僅僅只是為了后面演示時看得更清楚，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實現

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、測試程序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;/*** 演示在運行時，動態向容器中添加、移除Bean* author:菩提樹下的楊過 http://yjmyzz.cnblogs.cm/*/ public class AppDemo {public static void main(String[] args) {ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");//從context中取出FooA實例IFoo f = ctx.getBean(IFoo.class);f.foo();//FooA.foo()//輸出IFoo的Bean基本信息System.out.println(f.getClass());//class yjmyzz.FooAString beanName = ctx.getBeanNamesForType(IFoo.class)[0];System.out.println(beanName);//fooASystem.out.println(ctx.isSingleton(beanName));//true//銷毀FooA實例removeBean(ctx, beanName);System.out.println(ctx.containsBean(beanName));//falseSystem.out.println("------------");//注入新BeanbeanName = "fooB";addBean(ctx, beanName, FooB.class);//取出新實例f = ctx.getBean(beanName, IFoo.class);f.foo();//輸出IFoo的Bean基本信息System.out.println(f.getClass());beanName = ctx.getBeanNamesForType(IFoo.class)[0];System.out.println(beanName);//fooBSystem.out.println(ctx.isSingleton(beanName));//trueSystem.out.println("------------");showAllBeans(ctx);ctx.close();}/*** 向容器中動態添加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);}}/*** 從容器中移除Bean** @param ctx* @param beanName*/static void removeBean(AbstractRefreshableApplicationContext ctx, String beanName) {BeanDefinitionRegistry beanDefReg = (DefaultListableBeanFactory) ctx.getBeanFactory();beanDefReg.getBeanDefinition(beanName);beanDefReg.removeBeanDefinition(beanName);}/*** 遍歷輸出所有Bean的信息*/static void showAllBeans(AbstractRefreshableApplicationContext ctx) {//遍歷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> View Code

?

輸出：
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()

總結

以上是生活随笔為你收集整理的spring：如何用代码动态向容器中添加或移除Bean ？的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。