java 加载 Spring bean
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Load Spring bean
提问by Joe
Is there any way in Spring to load a bean specifically.
Spring 有什么方法可以专门加载 bean。
I've a appContext file having lots of beans. When loading it using the following code, it loads all beans again.
我有一个包含大量 bean 的 appContext 文件。使用以下代码加载它时，它会再次加载所有 bean。
BeanFactory factory = new ClassPathXmlApplicationContext("appContext.xml");
回答by tojofo
What about using ApplicationContextAware?
怎么用ApplicationContextAware？
Bean mapping
Bean映射
<bean id="springApplicationContext" class="SpringApplicationContext"/>
<bean id="springApplicationContext" class="SpringApplicationContext"/>
Java implementation
Java实现
public class SpringApplicationContext implements ApplicationContextAware {
private static ApplicationContext CONTEXT;
public void setApplicationContext(ApplicationContext ctx) throws BeansException {
CONTEXT = ctx;
}
public static Object getBean(String name) {
return CONTEXT.getBean(name);
}
}
Then use it like this;
然后像这样使用它；
SpringApplicationContext.getBean("myBean");
SpringApplicationContext.getBean("myBean");
回答by Roman
By default, spring creates instances of all singleton-scoped beans at startup.
默认情况下，springsingleton在启动时创建所有作用域 bean 的实例。
I would recommend you to split you spring configuration in several distinct files. In that case you'll be able to load only that group of beans which is required for your task.
我建议您将 spring 配置拆分为几个不同的文件。在这种情况下，您将只能加载您的任务所需的那组 bean。
Another way is to declare your beans with default-lazy-initattribute:
另一种方法是用default-lazy-init属性声明你的bean ：
<beans default-lazy-init="true">
<!-- no beans will be pre-instantiated... -->
</beans>
回答by user12384512
回答by pap
回答by beny23
This may help in order to avoid having to recreate a spring context.
这可能有助于避免重新创建 spring 上下文。
If you use Spring to configure the quartz jobthen you can reference spring beans directly from your job.
如果您使用Spring 配置石英作业，那么您可以直接从您的作业中引用 spring bean。
For example, if you use the MethodInvokingJobDetailFactoryBean, then you could create a bean that executes the code, which in turn calls your DAO.
例如，如果您使用MethodInvokingJobDetailFactoryBean，那么您可以创建一个执行代码的 bean，该 bean 又调用您的 DAO。
<bean id="exampleBusinessObject" class="my.pkg.BusinessObject">
<property name="dao" ref="myDao" />
</bean>
<bean id="exampleJob"
class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="exampleBusinessObject"/>
<property name="targetMethod" value="doIt"/>
</bean>
<bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean">
<property name="jobDetail" ref="exampleJob" />
<!-- run every 30 min -->
<property name="cronExpression" value="0 0/30 * * * ?" />
</bean>
