Spring(3.2.3)

创建一个 Bean 实例对象的方法通常有如下方式：

• 调用构造器创建 Bean 实例
• 调用静态工厂方法创建 Bean 实例
• 调用实例工厂方法创建 Bean 实例

xml 配置：

<bean id="exampleBean" class="examples.ExampleBean"/><bean name="anotherExample" class="examples.ExampleBeanTwo"/>

XML 配置：

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

静态工厂类：

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

XML 配置：

<!-- the factory bean, which contains a method called createInstance() --><bean id="serviceLocator" class="examples.DefaultServiceLocator">    <!-- inject any dependencies required by this locator bean --></bean><!-- the bean to be created via the factory bean --><bean id="clientService" factory-bean="serviceLocator" factory-method="createClientServiceInstance"/>

实例工厂类：

public class DefaultServiceLocator {    private static ClientService clientService = new ClientServiceImpl();    private DefaultServiceLocator() {}    public ClientService createClientServiceInstance() {        return clientService;    }}