Spring中使用inner bean

有点类似java 内部类。看个demo。假设有下面的一个bean：

public class Customer 
{
	private Person person;
 
	public Customer(Person person) {
		this.person = person;
	}
 
	public void setPerson(Person person) {
		this.person = person;
	}
 
	@Override
	public String toString() {
		return "Customer [person=" + person + "]";
	}
}

　　

public class Person 
{
	private String name;
	private String address;
	private int age;
 
	//getter and setter methods
 
	@Override
	public String toString() {
		return "Person [address=" + address + ", 
                               age=" + age + ", name=" + name + "]";
	}	
}

　　

<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-2.5.xsd">
 
	<bean id="CustomerBean" class="com.mkyong.common.Customer">
		<property name="person" ref="PersonBean" />
	</bean>
 
	<bean id="PersonBean" class="com.mkyong.common.Person">
		<property name="name" value="mkyong" />
		<property name="address" value="address1" />
		<property name="age" value="28" />
	</bean>
 
</beans>

　　

<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-2.5.xsd">
 
	<bean id="CustomerBean" class="com.mkyong.common.Customer">
		<property name="person">
			<bean class="com.mkyong.common.Person">
				<property name="name" value="mkyong" />
				<property name="address" value="address1" />
				<property name="age" value="28" />
			</bean>
		</property>
	</bean>
</beans>

　　我们也可以使用构造函数注入

<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-2.5.xsd">
 
	<bean id="CustomerBean" class="com.mkyong.common.Customer">
		<constructor-arg>
			<bean class="com.mkyong.common.Person">
				<property name="name" value="mkyong" />
				<property name="address" value="address1" />
				<property name="age" value="28" />
			</bean>
		</constructor-arg>
	</bean>
</beans>

　　Note
注意，在inner bean中，id和name不是必须的，因为他们会被容器忽略。

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
public class App 
{
    public static void main( String[] args )
    {
    	ApplicationContext context = 
    	  new ClassPathXmlApplicationContext(new String[] {"Spring-Customer.xml"});
 
    	Customer cust = (Customer)context.getBean("CustomerBean");
    	System.out.println(cust);
 
    }
}