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上篇文章介绍了标准的Blueprint 规范与 Gemini Blueprint如何自定义Bean配置文件路径,本文接着上篇文章继续介绍Blueprint的使用。
前面提到过,Gemini Blueprint即实现了Blueprint 规范,又兼容spring DM风格的配置,本节我们再来了解一下Blueprint与Spring DM在Bean的配置上的差异,具体如下表所示:
(注意:这两种风格Gemini Blueprint都支持。)
如上图所示,Spring DM风格的Bean配置和Blueprint还是有一些差异的,首先体现在根元素和命名空间声明上,Spring DM根元素为<beans>
,命名空间声明如下:
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"
- default-lazy-init="true">
-
- </beans>
而Blueprint根元素为<blueprint>
,命名空间声明如下:
- <?xml version="1.0" encoding="UTF-8"?>
- <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" default-activation="lazy">
-
- </blueprint>
相比之下,Blueprint的配置要稍微简单些,除了根元素和命名空间声明外,Bean的配置的主要差异如下:
1、Spring DM使用根元素的default-lazy-init属性指定IoC容器启动时是否立刻实例化所有的Bean,而Blueprint对应的属性为default-activation。
2、Spring DM可以通过default-init-method和default-destroy-method属性指定Bean实例化和销毁时默认的回调方法,还可以通过default-autowire, default-autowire-candidates属性指定Bean的自动装配策略,而这些属性Blueprint是不支持的。
3、Spring DM的Bean支持使用name属性,还支持使用alias属性为Bean指定一个别名,Blueprint是不支持的。
4、Spring DM 配置Bean的scope属性支持singleton, prototype, request, session, bundle等取值,而Blueprint Bean的scope属性仅仅支持singleton, prototype。
5、Spring DM通过Bean的lazy-init属性指定IoC容器启动时是否实例化该Bean,Blueprint对应的属性为activation。
6、Spring DM通过factory-bean属性指定工厂Bean,而Blueprint对应的属性为factory-ref。
7、Spring DM可以使用parent属性继承一个Bean的配置,而Blueprint不支持。
8、Spring DM 通过autowire, autowire-candidate属性指定Bean的自动装配策略,而Blueprint也是不支持的。
9、构造器注入时,Spring DM使用的标签为<constructor-arg>
,而Blueprint使用的标签为<argument>
。
Spring DM 和 Blueprint 风格的Bean的配置差异主要体现在上面几个方面,接下来我们开始学习Bean的注册与引用。
前面的文章中有提到过,OSGI应用的每一个Bundle都是使用不同的类加载器加载,OSGI应用并不像普通的Java应用一样,有全局的Classpath的概念,所以如果需要在一个Bundle中使用另外一个Bundle中的类,则需要另外一个Bundle导出这些类,然后在用到这些类的Bundle中导入即可。而OSGI应用对象的共享则是通过服务注册的方式实现。
使用Blueprint將Spring框架整合到OSGI中,ApplicationContext和普通的Java应用也有所差异。一般来说,普通Java应用的ApplicationContext只有一个,而且是全局的,而在OSGI应用中,每个Bundle对应一个单独个ApplicationContext,如下图所示:
从上图可以清晰的看出,每个Bundle对应的ApplicationContext是不同的,也就是说每个Bundle中配置的Bean是不共享的,例如当我们在A Bundle中定义了一个Bean,然后以属性注入的方式注入到B Bundle中的一个Bean中,这就有问题了,那么如何解决这个问题呢,Spring DM给出的解决方案是將Bean注册为服务,然后在其他Bundle中引用Bean。接下来我们就来学习一下Bean的注册与引用机制。
Spring DM Bean的注册与引用机制实际上有个缺点,它要求被注册的Bean必须实现了某个接口,为了方便说明问题,笔者在前面文章中搭建好的环境中进行演示,首先我们可以在com.csdn.osgi.common工程中新建一个com.csdn.osgi.domain.Employee接口,表示员工的信息,内容如下:
- package com.csdn.osgi.domain;
-
- public interface Employee {
-
- public String getName();
-
- public int getAge();
-
- public String getAddress();
-
- }
然后定义一个具体的类来实现Employee 接口,比如我们有实现类com.csdn.osgi.domain.Programmer,如下:
- package com.csdn.osgi.domain;
-
- public class Programmer implements Employee{
-
- private String name; // 员工姓名
-
- private int age; // 员工年龄
-
- private String address; // 居住地址
-
- private double salary; // 员工薪资
-
- public String getName() {
- return name;
- }
-
- public void setName(String name) {
- this.name = name;
- }
-
- public int getAge() {
- return age;
- }
-
- public void setAge(int age) {
- this.age = age;
- }
-
- public String getAddress() {
- return address;
- }
-
- public void setAddress(String address) {
- this.address = address;
- }
-
- public double getSalary() {
- return salary;
- }
-
- public void setSalary(double salary) {
- this.salary = salary;
- }
-
- }
接着在com.csdn.osgi.common工程中,新建 META-INF/spring/employee.xml文件,在新建的文件中,配置一个Programmer类的实例,如下:
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"
- default-lazy-init="false">
-
- <bean id="programmer" class="com.csdn.osgi.domain.Programmer">
- <property name="name" value="Smith"/>
- <property name="age" value="25"/>
- <property name="address" value="Nanjin"/>
- <property name="salary" value="2000"/>
- </bean>
-
- </beans>
如上面代码所示,我们在com.csdn.osgi.common这个Bundle中通过Spring实例化了一个Programmer对象,其他Bundle中如果需要注入这个实例,该怎样做呢?
接下来我们在com.csdn.osgi.helloworld工程中,新建一个Company类,表示公司信息,例如:
- package com.csdn.osgi.domain;
-
- public class Company {
-
- private String name; // 公司名称
-
- private Employee emp; // 假设只有一个员工
-
- public String getName() {
- return name;
- }
-
- public void setName(String name) {
- this.name = name;
- }
-
- public Employee getEmp() {
- return emp;
- }
-
- public void setEmp(Employee emp) {
- this.emp = emp;
- }
- }
项目结构如下图所示:
需要注意的是,Company类在com.csdn.osgi.helloworld这个Bundle中,而Programmer类在com.csdn.osgi.common中,我们需要在com.csdn.osgi.common这个Bundle中导出com.csdn.osgi.domain这个包,具体做法很简单,可以將com.csdn.osgi.common工程中的MANIFEST.MF文件,修改成如下内容:
- Manifest-Version: 1.0
- Bundle-ManifestVersion: 2
- Bundle-Name: Common
- Bundle-SymbolicName: com.csdn.osgi.common
- Bundle-Version: 1.0.0.qualifier
- Bundle-Activator: com.csdn.osgi.common.Activator
- Bundle-Vendor: CSDN
- Bundle-RequiredExecutionEnvironment: JavaSE-1.8
- Import-Package: org.osgi.framework;version="1.3.0"
- Export-Package: com.csdn.osgi.domain
其中Export-Package: com.csdn.osgi.domain
为新增内容,解决依赖问题后,我们可以在com.csdn.osgi.helloworld工程中,新建一个config/company.xml文件(注意:前面我们通过Spring-Context头自定义了Bean配置文件路径为config/*.xml),然后配置一个Company实例,内容如下:
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"
- default-lazy-init="false">
-
- <bean id="company" class="com.csdn.osgi.domain.Company">
- <property name="name" value="CSDN"/>
- <property name="emp" ref="programmer"/>
- </bean>
-
- </beans>
这里我们直接將com.csdn.osgi.common Bundle中配置的employee对象注入,然后启动OSGI容器,看看会有什么问题,控制台输出日志如下:
- 十二月 25, 2016 9:08:05 下午 org.eclipse.gemini.blueprint.extender.internal.boot.ChainActivator <init>
- 信息: Blueprint API detected; enabling Blueprint Container functionality
- 十二月 25, 2016 9:08:05 下午 org.eclipse.gemini.blueprint.extender.internal.activator.LoggingActivator start
- 信息: Starting [org.eclipse.gemini.blueprint.extender] bundle v.[2.0.0.M02]
- osgi> 十二月 25, 2016 9:08:05 下午 org.eclipse.gemini.blueprint.extender.internal.support.ExtenderConfiguration start
- 信息: No custom extender configuration detected; using defaults...
- 十二月 25, 2016 9:08:05 下午 org.springframework.scheduling.timer.TimerTaskExecutor afterPropertiesSet
- 信息: Initializing Timer
- hello world!
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.support.DefaultOsgiApplicationContextCreator createApplicationContext
- 信息: Discovered configurations {osgibundle:/META-INF/spring/*.xml} in bundle [Common (com.csdn.osgi.common)]
- Hello World!!
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.support.DefaultOsgiApplicationContextCreator createApplicationContext
- 信息: Discovered configurations {config/*.xml} in bundle [Helloworld (com.csdn.osgi.helloworld)]
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.blueprint.activator.support.BlueprintContainerCreator createApplicationContext
- 信息: Discovered configurations {bundleentry://43.fwk1878169648/OSGI-INF/blueprint/beans.xml} in bundle [Helloworld (com.csdn.osgi.helloworld)]
- 十二月 25, 2016 9:08:06 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
- 信息: Refreshing OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.common, config=osgibundle:/META-INF/spring/*.xml): startup date [Sun Dec 25 21:08:06 CST 2016]; root of context hierarchy
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext unpublishContextAsOsgiService
- 信息: Application Context service already unpublished
- 十二月 25, 2016 9:08:06 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
- 信息: Refreshing OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=config/*.xml): startup date [Sun Dec 25 21:08:06 CST 2016]; root of context hierarchy
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext unpublishContextAsOsgiService
- 信息: Application Context service already unpublished
- 十二月 25, 2016 9:08:06 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
- 信息: Refreshing OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=bundleentry://43.fwk1878169648/OSGI-INF/blueprint/beans.xml): startup date [Sun Dec 25 21:08:06 CST 2016]; root of context hierarchy
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext unpublishContextAsOsgiService
- 信息: Application Context service already unpublished
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from OSGi resource[bundleentry://43.fwk1878169648/OSGI-INF/blueprint/beans.xml|bnd.id=43|bnd.sym=com.csdn.osgi.helloworld]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://43.fwk1878169648/config/beans.xml]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://37.fwk1878169648/META-INF/spring/beans.xml]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://43.fwk1878169648/config/company.xml]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://37.fwk1878169648/META-INF/spring/dmconfig.xml]
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor stageOne
- 信息: No outstanding OSGi service dependencies, completing initialization for OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=bundleentry://43.fwk1878169648/OSGI-INF/blueprint/beans.xml)
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://43.fwk1878169648/config/dmconfig.xml]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
- 信息: Loading XML bean definitions from URL [bundleentry://37.fwk1878169648/META-INF/spring/employee.xml]
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
- 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@48766948: defining beans [helloWorld,blueprintBundle,blueprintBundleContext,blueprintContainer,blueprintConverter]; root of factory hierarchy
- ================Hello World================
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor stageOne
- 信息: No outstanding OSGi service dependencies, completing initialization for OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=config/*.xml)
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor stageOne
- 信息: No outstanding OSGi service dependencies, completing initialization for OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.common, config=osgibundle:/META-INF/spring/*.xml)
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
- 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@6ec2b45d: defining beans [object,length,buffer,current-time,list,programmer]; root of factory hierarchy
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
- 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@30a0eb63: defining beans [helloWorld1,helloWorld2,company]; root of factory hierarchy
- ================Hello World================
- ================Hello World================
- =========Company=========
- 十二月 25, 2016 9:08:06 下午 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons
- 信息: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@30a0eb63: defining beans [helloWorld1,helloWorld2,company]; root of factory hierarchy
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.support.DefaultOsgiBundleApplicationContextListener onOsgiApplicationEvent
- 严重: Application context refresh failed (OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=config/*.xml))
- org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'company' defined in URL [bundleentry://43.fwk1878169648/config/company.xml]: Cannot resolve reference to bean 'programmer' while setting bean property 'emp'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'programmer' is defined
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1305)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1067)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:511)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:450)
- at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:290)
- at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
- at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:287)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
- at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:557)
- at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:842)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:60)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:325)
- at org.eclipse.gemini.blueprint.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:290)
- at org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:137)
- at java.lang.Thread.run(Thread.java:745)
- Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'programmer' is defined
- at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:504)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1041)
- at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:273)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
- ... 17 more
-
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext unpublishContextAsOsgiService
- 信息: Application Context service already unpublished
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.blueprint.container.support.BlueprintContainerServicePublisher registerService
- 信息: Publishing BlueprintContainer as OSGi service with properties {Bundle-SymbolicName=com.csdn.osgi.helloworld, Bundle-Version=1.0.0.qualifier, osgi.blueprint.container.version=1.0.0.qualifier, osgi.blueprint.container.symbolicname=com.csdn.osgi.helloworld}
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.support.DefaultOsgiBundleApplicationContextListener onOsgiApplicationEvent
- 信息: Application context succesfully closed (OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=config/*.xml))
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor fail
- 严重: Unable to create application context for [com.csdn.osgi.helloworld], unsatisfied dependencies: none
- org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'company' defined in URL [bundleentry://43.fwk1878169648/config/company.xml]: Cannot resolve reference to bean 'programmer' while setting bean property 'emp'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'programmer' is defined
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328)
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1305)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1067)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:511)
- at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:450)
- at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:290)
- at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
- at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:287)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
- at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:557)
- at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:842)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:60)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:325)
- at org.eclipse.gemini.blueprint.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
- at org.eclipse.gemini.blueprint.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:290)
- at org.eclipse.gemini.blueprint.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:137)
- at java.lang.Thread.run(Thread.java:745)
- Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'programmer' is defined
- at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:504)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1041)
- at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:273)
- at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
- at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:322)
- ... 17 more
-
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext publishContextAsOsgiServiceIfNecessary
- 信息: Publishing application context as OSGi service with properties {org.eclipse.gemini.blueprint.context.service.name=com.csdn.osgi.helloworld, org.springframework.context.service.name=com.csdn.osgi.helloworld, Bundle-SymbolicName=com.csdn.osgi.helloworld, Bundle-Version=1.0.0.qualifier}
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.support.DefaultOsgiBundleApplicationContextListener onOsgiApplicationEvent
- 信息: Application context successfully refreshed (OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.helloworld, config=bundleentry://43.fwk1878169648/OSGI-INF/blueprint/beans.xml))
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.context.support.AbstractOsgiBundleApplicationContext publishContextAsOsgiServiceIfNecessary
- 信息: Publishing application context as OSGi service with properties {org.eclipse.gemini.blueprint.context.service.name=com.csdn.osgi.common, org.springframework.context.service.name=com.csdn.osgi.common, Bundle-SymbolicName=com.csdn.osgi.common, Bundle-Version=1.0.0.qualifier}
- 十二月 25, 2016 9:08:06 下午 org.eclipse.gemini.blueprint.extender.internal.support.DefaultOsgiBundleApplicationContextListener onOsgiApplicationEvent
- 信息: Application context successfully refreshed (OsgiBundleXmlApplicationContext(bundle=com.csdn.osgi.common, config=osgibundle:/META-INF/spring/*.xml))
错误信息意思很明显,名称为programmer这个Bean未定义,原因是该Bean定义在com.csdn.osgi.common这个Bundle中,在com.csdn.osgi.helloworld Bundle中无法直接访问,接下来我们通过Bean的注册和引用来解决该问题。
在com.csdn.osgi.common工程中,新建一个META-INF/spring/dmconfig.xml文件,用来注册Bean,内容如下:
- <?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:osgi="http://www.eclipse.org/gemini/blueprint/schema/blueprint"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans.xsd
- http://www.eclipse.org/gemini/blueprint/schema/blueprint
- http://www.eclipse.org/gemini/blueprint/schema/blueprint/gemini-blueprint.xsd">
-
- <osgi:service id="employee" ref="programmer" interface="com.csdn.osgi.domain.Employee" />
-
- </beans>
然后在com.csdn.osgi.helloworld Bundle中,新建config/dmconfig.xml文件,我们在该文件中引入其他Bundle中注册的Bean,内容如下:
- <?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:osgi="http://www.eclipse.org/gemini/blueprint/schema/blueprint"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans.xsd
- http://www.eclipse.org/gemini/blueprint/schema/blueprint
- http://www.eclipse.org/gemini/blueprint/schema/blueprint/gemini-blueprint.xsd">
-
- <osgi:reference id="employee" interface="com.csdn.osgi.domain.Employee" />
-
- <alias name="employee" alias="programmer"/>
-
- </beans>
需要注意的是,<osgi:service/>
标签的id属性值不能和Bean的id相同。上面的配置中我们使用<alias/>
标签为employee指定别名为programmer,然后重启OSGI容器,会发现com.csdn.osgi.common Bundle中定义的名称为programmer的Bean成功注入到Company类中。
Bean的注册与引用机制对项目开发非常重要,在后面整合Mybatis时,我们可以將用于操作数据库的SqlSessionTemplate注册为服务,然后在其他Bundle就可以引用该服务操作数据库了。
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