1.整合spring+hibernate中，讓spring接管hibernate的session工廠有一段代碼
[java]
<bean id="sFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
查看源碼：org.springframework.orm.hibernate3.LocalSessionFactoryBean:
[java]
public class LocalSessionFactoryBean extends AbstractSessionFactoryBean implements BeanClassLoaderAware
在到AbstractSessionFactoryBean:
[java]
public abstract class AbstractSessionFactoryBean
implements FactoryBean<SessionFactory>, InitializingBean, DisposableBean, PersistenceExceptionTranslator
發現瞭實現瞭一個factoryBean<T>,裡面給瞭個泛型(SeesionFactory).
註：這個bean和其他的bean不一樣,spring中有兩種bean.
普通bean和bean工廠,即FactoryBean. FactoryBean 返回的不是這個類的實例，其返回的是該工廠Bean的getObject()方法所返回的對象
普通的Bean直接返回指定類(配置中的class屬性的值)的一個實例.
一個小例子：
[java]
package org.ymm.entity;
import org.springframework.beans.factory.FactoryBean;
/**
* TestBean 類實現瞭FactoryBean<T>
* @author witho_000
*
*/
public class TestBean implements FactoryBean<Object>{
public Object getObject() throws Exception {
// TODO Auto-generated method stub
return "string類型";
}
@Override
public Class<?> getObjectType() {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean isSingleton() {
// TODO Auto-generated method stub
return false;
}
}
[java]
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="https://www.springframework.org/schema/beans"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xmlns:context="https://www.springframework.org/schema/context"
xsi:schemaLocation="https://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans-3.0.xsd
https://www.springframework.org/schema/context
https://www.sprinsgframework.org/schema/context/spring-context-3.0.xsd">
<!– 測試factorybean –>
<bean id="factorybean1" class="org.ymm.entity.TestBean" />
</beans>
[java]
package org.ym.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.ymm.entity.TestBean;
/**
* Tester測試類
* @author witho_000
*
*/
public class Tester {
public static void main(String[] args) {
ApplicationContext cont=new ClassPathXmlApplicationContext("beans.xml");
String s= cont.getBean("&factorybean1",String.class);
System.out.println(s.getClass());
}
}
顯然沒有報錯，返回的正是String類型。而不是spring配置的TestBean類型;
網上找到的小技巧：
String s= cont.getBean("&factorybean1",String.class);
bean的id前加個&得到的就是TestBean
作者:without0815