這篇文章主要介紹“怎么用Factory Bean讓Spring配置動起來”,在日常操作中,相信很多人在怎么用Factory Bean讓Spring配置動起來問題上存在疑惑,小編查閱了各式資料,整理出簡單好用的操作方法,希望對大家解答”怎么用Factory Bean讓Spring配置動起來”的疑惑有所幫助!接下來,請跟著小編一起來學(xué)習(xí)吧!
創(chuàng)新互聯(lián)是一家專注于成都網(wǎng)站制作、網(wǎng)站建設(shè)與策劃設(shè)計,正安網(wǎng)站建設(shè)哪家好?創(chuàng)新互聯(lián)做網(wǎng)站,專注于網(wǎng)站建設(shè)十多年,網(wǎng)設(shè)計領(lǐng)域的專業(yè)建站公司;建站業(yè)務(wù)涵蓋:正安等地區(qū)。正安做網(wǎng)站價格咨詢:18982081108
不少朋友討論spring配置時認(rèn)為spring配置中只能靜態(tài)的設(shè)置一些參數(shù)(典型情況如數(shù)據(jù)庫配置, 定時器配置等)導(dǎo)致不方便, 其實spring已經(jīng)提供了非常便利的方式來實現(xiàn)動態(tài)spring配置, 我們要做的只是實現(xiàn)一個自己的 Factory Bean , 來看一下 Factory Bean 接口的定義
/**//**
* Interface to be implemented by objects used within a BeanFactory
* that are themselves factories. If a bean implements this interface,
* it is used as a factory, not directly as a bean.
*
* <p><b>NB: A bean that implements this interface cannot be used
* as a normal bean.</b> A FactoryBean is defined in a bean style,
* but the object exposed for bean references is always the object
* that it creates.
* <p>FactoryBeans can support singletons and prototypes, and can
* either create objects lazily on demand or eagerly on startup.
*
* <p>This interface is heavily used within the framework, for
* example for the AOP ProxyFactoryBean or JndiObjectFactoryBean.
* It can be used for application components, but this is not common
* outside of infrastructure code.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 08.03.2003
* @see org.springframework.beans.factory.BeanFactory
* @see org.springframework.aop.framework.ProxyFactoryBean
* @see org.springframework.jndi.JndiObjectFactoryBean
*/
public interface FactoryBean ...{
/**//**
* Return an instance (possibly shared or independent) of the object
* managed by this factory. As with a BeanFactory, this allows
* support for both the Singleton and Prototype design pattern.
* <p>If this method returns <code>null</code>, the factory will consider
* the FactoryBean as not fully initialized and throw a corresponding
* FactoryBeanNotInitializedException.
* @return an instance of the bean (should not be <code>null</code>;
* a <code>null</code> value will be considered as an indication of
* incomplete initialization)
* @throws Exception in case of creation errors
* @see FactoryBeanNotInitializedException
*/
Object getObject() throws Exception;
/**//**
* Return the type of object that this FactoryBean creates, or <code>null</code>
* if not known in advance. This allows to check for specific types
* of beans without instantiating objects, for example on autowiring.
* <p>For a singleton, this should try to avoid singleton creation
* as far as possible; it should rather estimate the type in advance.
* For prototypes, returning a meaningful type here is advisable too.
* <p>This method can be called <i>before</i> this FactoryBean has
* been fully initialized. It must not rely on state created during
* initialization; of course, it can still use such state if available.
* <p><b>NOTE:</b> Autowiring will simply ignore FactoryBeans that return
* <code>null</code> here. Therefore it is highly recommended to implement
* this method properly, using the current state of the FactoryBean.
* @return the type of object that this FactoryBean creates,
* or <code>null</code> if not known at the time of the call
* @see ListableBeanFactory#getBeansOfType
*/
Class getObjectType();
/**//**
* Is the bean managed by this factory a singleton or a prototype?
* That is, will <code>getObject()</code> always return the same object
* (a reference that can be cached)?
* <p><b>NOTE:</b> If a FactoryBean indicates to hold a singleton object,
* the object returned from <code>getObject()</code> might get cached
* by the owning BeanFactory. Hence, do not return <code>true</code>
* unless the FactoryBean always exposes the same reference.
* <p>The singleton status of the FactoryBean itself will generally
* be provided by the owning BeanFactory; usually, it has to be
* defined as singleton there.
* @return if this bean is a singleton
* @see #getObject()
*/
boolean isSingleton();
}
看了以后發(fā)現(xiàn), Factory Bean 用于在spring容器中創(chuàng)建其他的Bean, 我們平時用得最多的 JndiObjectFactory Bean, hibernate 的 LocalSessionFactory Bean 都是 Factory Bean 的具體實現(xiàn), 既然如此, 讀取動態(tài)配置就變得易如反掌了, 假如我們要實現(xiàn)動態(tài)讀取數(shù)據(jù)庫配置的功能, 拿使用率***的 BasicDatasource 為例, 簡單的實現(xiàn)一個 BasicDatasource Factory Bean 如下即可
public class BasicDataSourceFactoryBean implements FactoryBean ...{
public Object getObject() throws Exception ...{
BasicDataSource dataSource = new BasicDataSource();
// 讀取外部配置, 設(shè)置到 dataSource 中 ...
return dataSource;
}
public Class getObjectType() ...{
return BasicDataSource.class;
}
public boolean isSingleton() ...{
return true;
}
}
然后在 spring 中如此聲明
<bean id="dataSource" class="BasicDataSourceFactoryBean ">
... 你的配置來源
</bean>
到此,關(guān)于“怎么用Factory Bean讓Spring配置動起來”的學(xué)習(xí)就結(jié)束了,希望能夠解決大家的疑惑。理論與實踐的搭配能更好的幫助大家學(xué)習(xí),快去試試吧!若想繼續(xù)學(xué)習(xí)更多相關(guān)知識,請繼續(xù)關(guān)注創(chuàng)新互聯(lián)網(wǎng)站,小編會繼續(xù)努力為大家?guī)砀鄬嵱玫奈恼拢?/p>
本文題目:怎么用FactoryBean讓Spring配置動起來
網(wǎng)址分享:http://bm7419.com/article14/psddge.html
成都網(wǎng)站建設(shè)公司_創(chuàng)新互聯(lián),為您提供外貿(mào)網(wǎng)站建設(shè)、網(wǎng)站策劃、App開發(fā)、動態(tài)網(wǎng)站、外貿(mào)建站、用戶體驗
聲明:本網(wǎng)站發(fā)布的內(nèi)容(圖片、視頻和文字)以用戶投稿、用戶轉(zhuǎn)載內(nèi)容為主,如果涉及侵權(quán)請盡快告知,我們將會在第一時間刪除。文章觀點不代表本網(wǎng)站立場,如需處理請聯(lián)系客服。電話:028-86922220;郵箱:631063699@qq.com。內(nèi)容未經(jīng)允許不得轉(zhuǎn)載,或轉(zhuǎn)載時需注明來源: 創(chuàng)新互聯(lián)