SpringIoC Container and beans

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

Using the method T getBean(Stringname, Class<T>
requiredType) you can retrieve instances of your beans.

// retrieve configured instance
PetStoreServiceImpl service = context.getBean("petStore", PetStoreServiceImpl.class);
// use configured instance
List userList service.getUsernameList();

Instantiating beans
Most Spring users prefer actual JavaBeans with only a default (no-argument)
constructor and appropriate setters and getters modeled after the properties in the container

1：Instantiation with a constructor

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

2：Instantiation with a static factory method

<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;
}
}

3：Instantiation using an instance factory method

<!-- 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"/>

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">
<!-- inject any dependencies required by this locator bean -->
</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;
}
}

引用

Note
In Spring documentation, factory bean refers to a bean that is configured in the Spring
container that will create objects through an instance or static factory method. By contrast,
FactoryBean (notice the capitalization) refers to a Spring-specific FactoryBean