前言

有一种情况当ioc的一个bean由于异常原因导致的不可用,必须需要重新注册一个bean，来替换当前的bean．

package cn.freemud.order.settlement.core.config;

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.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.stereotype.Component;

/**
 * @Author hongwang.zhang
 * @Description
 * @Date 上午11:00 21-3-4
 * @Param
 * @return
 **/
@Component
public class BeanHolder {

    private final ConfigurableApplicationContext applicationContext;


    public BeanHolder(ConfigurableApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    public ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    /**
     * 根据构造参数注入
     *
     * @param beanName
     * @param clazz
     * @param args
     * @param <T>
     * @return
     */
    public <T> T registerBeanConstruct(String beanName, Class<T> clazz, Object... args) {
        // 创建bean信息.
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
        if (args.length > 0) {
            for (Object arg : args) {
                beanDefinitionBuilder.addConstructorArgValue(arg);
            }
        }
        BeanDefinition beanDefinition = beanDefinitionBuilder.getRawBeanDefinition();
        BeanDefinitionRegistry beanFactory = (BeanDefinitionRegistry) applicationContext.getBeanFactory();
        beanFactory.registerBeanDefinition(beanName, beanDefinition);
        return applicationContext.getBean(beanName, clazz);
    }


    /**
     * 删除beandefinition
     * @param beanName
     */
    public void removeBeanDefinition(String beanName) {
        // 获取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory) applicationContext
                .getAutowireCapableBeanFactory();
        defaultListableBeanFactory.removeBeanDefinition(beanName);
    }


}

• 替换老的bean重新注册一个对象,TestsDao 依赖这个对象的会自动获取最新的bean　ioc

 ApplicationContext applicationContext = beanHolder.getApplicationContext();
        System.out.println(testsDao);
        beanHolder.removeBeanDefinition("testdao");
        TestsDao testsDao１１ = beanHolder.registerBeanConstruct("testdao", TestsDao.class, "ZHW");

@Getter
@Setter
@ToString
@Component("testdao")
public class TestsDao {

    private  String name="default";

    public TestsDao(@Autowired(required =  false)String name) {
        System.out.println("动态注入"+name);
        this.name = name;
    }
}