Spring之动态注册bean的实现方法

2019-11-26 09:45:54

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Spring之动态注册bean

什么场景下，需要主动向Spring容器注册bean呢？

如我之前做个的一个支持扫表的基础平台，使用者只需要添加基础配置 + Groovy任务，就可以丢到这个平台上面来运行了，而这个基础平台是一直都在运行的，所以在新来任务时，最直观需要注册的就是 DataSource 数据源这个bean了，那么可以怎么玩？

I. 主动注册Bean支持

借助BeanDefinition来实现bean的定义，从最终的使用来看，代码比较少，几行而已

public <T> T registerBean(String name, Class<T> clazz, Object... args) {   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(name, beanDefinition);   return applicationContext.getBean(name, clazz);}

测试如下

import com.github.hui.story.quickstory.server.VisitService;import lombok.ToString;import org.springframework.beans.factory.annotation.Autowired;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.ConfigurableApplicationContext;import org.springframework.stereotype.Component;@Componentpublic class BeanHolder {  private final ConfigurableApplicationContext applicationContext;  public BeanHolder(ConfigurableApplicationContext applicationContext) {    this.applicationContext = applicationContext;    initSer();  }  public void initSer() {    InrSer ser = registerBean("test", InrSer.class);    ser.name = "一灰";    ser.uid = 22;    System.out.println(ser);    InrSer ser2 = registerBean("test2", InrSer.class, "一灰灰Blog", 20);    System.out.println(ser2);  }  @ToString  public static class InrSer {    private String name;    private Integer uid;    @Autowired    private VisitService visitService;    public InrSer() {    }    public InrSer(String name, Integer uid) {      this.name = name;      this.uid = uid;    }  }  private <T> T registerBean(String name, Class<T> clazz, Object... args) {    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(name, beanDefinition);    return applicationContext.getBean(name, clazz);  }}

输出如下