springboot设置父模块 springboot有父子容器吗

spring中父子容器的实现可以通过ConfigurableApplicationContext或ConfigurableBeanFactory来实现，这两个接口中分别有setParent及setParentBeanFactory方法，可以与当前的子容器进行父子容器关联，这个时候子容器就可以引用父容器中的bean，但是父容器是不能够引用子容器中的bean的，并且各个子容器中定义的bean是互不可见的，这样也可以避免因为不同的插件定义了相同的bean而带来的麻烦。应用场景包括插件或组件的接入，只需要对方提供JAR即可，由父容器进行引导，各个子容器再完成自己的应该完成的工作即可

package com.yaspeed.spring.parentChild;

public class Iphone7 {
	private String name;
	private int price;
	public Iphone7(){
		System.out.println("调用构造函数Iphone7()...");
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getPrice() {
		return price;
	}
	public void setPrice(int price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Iphone7 [name=" + name + ", price=" + price + "]";
	}

	public void print(){  
        System.out.println("This is parent class.");  
    } 
	
}

<?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:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="iphone7" class="com.yaspeed.spring.parentChild.Iphone7" scope="singleton"
		 p:name="iphone7plus" p:price="7188">
	</bean>	
	<bean id="pluginLoader" class="com.yaspeed.spring.parentChild.LoaderChild" init-method="load"></bean>  
</beans>

package com.yaspeed.spring.parentChild;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class LoaderChild implements ApplicationContextAware{
    ApplicationContext parentCtx;  
    ConfigurableApplicationContext childCtx;  
  
    public void load() {   
    	childCtx = new ClassPathXmlApplicationContext("classpath*:/middleware_*.xml");  
    	childCtx.setParent(parentCtx);
    	childCtx.refresh();
    }  
  
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
        this.parentCtx = applicationContext;  
    }    
}

<?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:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="childCtx1" class="com.yaspeed.spring.parentChild.ChildCtx1"></bean> 
	<bean id="childCtx2" class="com.yaspeed.spring.parentChild.ChildCtx2"></bean> 
</beans>

package com.yaspeed.spring.parentChild;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ChildCtx1 implements ApplicationContextAware {  
    
    ApplicationContext parentApplicationContext;  
  
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
      //父容器中没有建立父子容器关系之前，是获取不到parent的，只有父容器执行refresh方法后，第二次初使化子容器才会获取得到  
      //也就是第一次的初使化就不执行了，等父容器中建立好父子容器关系后再进行初使化，因为子容器需要引用父容器中的parentClass  
        if(applicationContext.getParent()==null){  
            return;  
        }  
        //Get parent application context  
        this.parentApplicationContext = applicationContext.getParent();  
  
        ConfigurableApplicationContext  childCtx1 = new ClassPathXmlApplicationContext("classpath:/child1.xml");  
        childCtx1.setParent(this.parentApplicationContext);  
        childCtx1.refresh();  
        Iphone7 iphone7 = childCtx1.getBean(Iphone7.class);  
        System.out.println("childCtx1-->"+iphone7);
    }  
  
}

package com.yaspeed.spring.parentChild;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ChildCtx2 implements ApplicationContextAware {  
    
    ApplicationContext parentApplicationContext;  
  
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {  
      //父容器中没有建立父子容器关系之前，是获取不到parent的，只有父容器执行refresh方法后，第二次初使化子容器才会获取得到  
      //也就是第一次的初使化就不执行了，等父容器中建立好父子容器关系后再进行初使化，因为子容器需要引用父容器中的parentClass  
        if(applicationContext.getParent()==null){  
            return;  
        }  
        //Get parent application context  
        this.parentApplicationContext = applicationContext.getParent();  
  
        ConfigurableApplicationContext  childCtx2 = new ClassPathXmlApplicationContext("classpath:/child2.xml");  
        childCtx2.setParent(this.parentApplicationContext);  
        childCtx2.refresh();  
        Iphone7 iphone7 = childCtx2.getBean(Iphone7.class);
        System.out.println("childCtx2-->"+iphone7);
    }  
  
}

package com.yaspeed.spring.parentChild;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;

public class Child1 implements InitializingBean {  
    //这里required加上false，是因为是没有建立父子容器关系之前，这个parentClass是注入不了了的  
      @Autowired(required = false)  
      Iphone7 parentClass;  
    
    //这里required加上false，是因为子容器之前是不能够相互引用的
      @Autowired(required = false)  
      Child2 childClass2;
    
      public void print() {  
          if (parentClass != null) {  
              parentClass.print();  
          }  
          System.out.println("This is child class 1");  
          if (childClass2 != null) { 
        	  System.out.println("childClass2 is not null!!");
              childClass2.print();  
          }  
      }  
    
      public void afterPropertiesSet() throws Exception {  
    	  System.out.println("child1-->afterPropertiesSet...");
          print();  
    
      }  
  }

<?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:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"> </bean>  
	<bean id="child1" class="com.yaspeed.spring.parentChild.Child1">  </bean>
</beans>

package com.yaspeed.spring.parentChild;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;

public class Child2 implements InitializingBean {  
    //这里required加上false，是因为是没有建立父子容器关系之前，这个parentClass是注入不了了的  
      @Autowired(required = false)  
      Iphone7 parentClass;  
  
      public void print() {  
          if (parentClass != null) {  
              parentClass.print();  
          }  
          System.out.println("This is child class 2");  
      }  
    
      public void afterPropertiesSet() throws Exception {
    	  System.out.println("child2-->afterPropertiesSet...");
          print();  
    
      }  
  }

<?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:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"> </bean>  
	<bean id="child2" class="com.yaspeed.spring.parentChild.Child2">  </bean>
</beans>

package com.yaspeed.spring.parentChild;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {
	//启动父容器
	public static void main(String[] args){  
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath*:/bean-parent.xml");  
    }  
}

测试结果：

九月 19, 2016 3:39:51 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@7106e68e: startup date [Mon Sep 19 15:39:51 CST 2016]; root of context hierarchy
九月 19, 2016 3:39:51 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from URL [file:/E:/workspace/drools/spring/bin/bean-parent.xml]
调用构造函数Iphone7()...
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3f49dace: startup date [Mon Sep 19 15:39:52 CST 2016]; root of context hierarchy
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [E:\workspace\drools\spring\bin\middleware_1.xml]
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@3f49dace: startup date [Mon Sep 19 15:39:52 CST 2016]; parent: org.springframework.context.support.ClassPathXmlApplicationContext@7106e68e
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from file [E:\workspace\drools\spring\bin\middleware_1.xml]
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@66480dd7: startup date [Mon Sep 19 15:39:52 CST 2016]; root of context hierarchy
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [child1.xml]
child1-->afterPropertiesSet...
This is child class 1
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@66480dd7: startup date [Mon Sep 19 15:39:52 CST 2016]; parent: org.springframework.context.support.ClassPathXmlApplicationContext@7106e68e
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [child1.xml]
child1-->afterPropertiesSet...
This is parent class.
This is child class 1
childCtx1-->Iphone7 [name=iphone7plus, price=7188]
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@22a67b4: startup date [Mon Sep 19 15:39:52 CST 2016]; root of context hierarchy
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [child2.xml]
child2-->afterPropertiesSet...
This is child class 2
九月 19, 2016 3:39:52 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@22a67b4: startup date [Mon Sep 19 15:39:52 CST 2016]; parent: org.springframework.context.support.ClassPathXmlApplicationContext@7106e68e
九月 19, 2016 3:39:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [child2.xml]
child2-->afterPropertiesSet...
This is parent class.
This is child class 2
childCtx2-->Iphone7 [name=iphone7plus, price=7188]