spring1

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源码学习第一天：

org.springframework.beans 和org.springframework.context 包是ioc 容器的基础包。

BeanFactory 接口：负责通过配置机制管理任何类型对象。

ApplicationContext 接口：继承BeanFactory

可以和aop ，消息资源处理（国际化），事件发布集成。

webApplicationContext 是应用层的上下文。

beans ：被ioc 容器管理的对象。

org.springframework.context.ApplicationContext 接口代表ioc 容器。

负责实例化，配置，装载beans

容器做这些工作是在配置文件或者注解中或者java 代码中获取指令。

ClassPathXmlApplicationContext

FileSystemXmlApplicationContext

是 ioc 容器的子类。

配置文件

实例化 ApplicationContext

ApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "services.xml", "daos.xml"});

<?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">



<bean id="petStore" class="org.springframework.samples.jpetstore.services.PetStoreServiceImpl">
<property name="accountDao" ref="accountDao"/>
<property name="itemDao" ref="itemDao"/>

</bean>



</beans>

The following example shows the data access objects daos.xml file:

<?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">

<bean id="accountDao"
class="org.springframework.samples.jpetstore.dao.jpa.JpaAccountDao">

</bean>

<bean id="itemDao" class="org.springframework.samples.jpetstore.dao.jpa.JapItemDao">

</bean>



</beans>

import 标签

获取对象T getBean(String name, Class<T> requiredType)

ApplicationContext context =
newClassPathXmlApplicationContext(newString[] {"services.xml", "daos.xml"});
// retrieve configured instance
PetStoreService service = context.getBean("petStore", PetStoreService.class);
// use configured instance
List<String> userList = service.getUsernameList();

bean 属性

起别名：

定义创建对象的工厂方法

<bean id="clientService"
class="examples.ClientService"
factory-method="createInstance"/>

public class ClientService {
private static ClientService clientService = new ClientService();
private ClientService() {}

public static ClientService createInstance() {
return clientService;
}
}

同一个bean如何定义多个创建对象的工厂方法

<bean id="serviceLocator" class="examples.DefaultServiceLocator">

</bean>


<bean id="clientService"
factory-bean="serviceLocator"
factory-method="createClientServiceInstance"/>

public class DefaultServiceLocator {

private static ClientService clientService = new ClientServiceImpl();
private DefaultServiceLocator() {}

public ClientService createClientServiceInstance() {
return clientService;
}
}

One factory class can also hold more than one factory method as shown here:

<bean id="serviceLocator" class="examples.DefaultServiceLocator">

</bean>

<bean id="clientService"
factory-bean="serviceLocator"
factory-method="createClientServiceInstance"/>

<bean id="accountService"
factory-bean="serviceLocator"
factory-method="createAccountServiceInstance"/>

public class DefaultServiceLocator {

private static ClientService clientService = new ClientServiceImpl();
private static AccountService accountService = new AccountServiceImpl();

private DefaultServiceLocator() {}

public ClientService createClientServiceInstance() {
return clientService;
}

public AccountService createAccountServiceInstance() {
return accountService;
}

}

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