Spring 集合 (List, Set, Map, and Properties) 使用示例

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Spring支持将值注入到四种集合类型当中，这四种集合类型分别是：

• List – <list/>
• Set – <set/>
• Map – <map/>
• Properties – <props/>

Spring beans

以下是一个有四个集合属性的Customer类：

package com.mkyong.common;

import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

public class Customer
{
	private List<Object> lists;
	private Set<Object> sets;
	private Map<Object, Object> maps;
	private Properties pros;

	//...
}

接下来我们看看如何在XML中声明这几种集合。

1. List 集合

<property name="lists">
	<list>
		<value>1</value>
		<ref bean="PersonBean" />
		<bean class="com.mkyong.common.Person">
			<property name="name" value="mkyongList" />
			<property name="address" value="address" />
			<property name="age" value="28" />
		</bean>
	</list>
</property>

2. Set 集合

<property name="sets">
	<set>
		<value>1</value>
		<ref bean="PersonBean" />
		<bean class="com.mkyong.common.Person">
			<property name="name" value="mkyongSet" />
			<property name="address" value="address" />
			<property name="age" value="28" />
		</bean>
	</set>
</property>

3. Map 集合

<property name="maps">
	<map>
		<entry key="Key 1" value="1" />
		<entry key="Key 2" value-ref="PersonBean" />
		<entry key="Key 3">
			<bean class="com.mkyong.common.Person">
				<property name="name" value="mkyongMap" />
				<property name="address" value="address" />
				<property name="age" value="28" />
			</bean>
		</entry>
	</map>
</property>

4、Properties集合

<property name="pros">
	<props>
		<prop key="admin">admin@nospam.com</prop>
		<prop key="support">support@nospam.com</prop>
	</props>
</property>

##5、完整的配置

<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">

		<!-- java.util.List -->
		<property name="lists">
			<list>
				<value>1</value>
				<ref bean="PersonBean" />
				<bean class="com.mkyong.common.Person">
					<property name="name" value="mkyongList" />
					<property name="address" value="address" />
					<property name="age" value="28" />
				</bean>
			</list>
		</property>

		<!-- java.util.Set -->
		<property name="sets">
			<set>
				<value>1</value>
				<ref bean="PersonBean" />
				<bean class="com.mkyong.common.Person">
					<property name="name" value="mkyongSet" />
					<property name="address" value="address" />
					<property name="age" value="28" />
				</bean>
			</set>
		</property>

		<!-- java.util.Map -->
		<property name="maps">
			<map>
				<entry key="Key 1" value="1" />
				<entry key="Key 2" value-ref="PersonBean" />
				<entry key="Key 3">
					<bean class="com.mkyong.common.Person">
						<property name="name" value="mkyongMap" />
						<property name="address" value="address" />
						<property name="age" value="28" />
					</bean>
				</entry>
			</map>
		</property>

		<!-- java.util.Properties -->
		<property name="pros">
			<props>
				<prop key="admin">admin@nospam.com</prop>
				<prop key="support">support@nospam.com</prop>
			</props>
		</property>

	</bean>

	<bean id="PersonBean" class="com.mkyong.common.Person">
		<property name="name" value="mkyong1" />
		<property name="address" value="address 1" />
		<property name="age" value="28" />
	</bean>

</beans>

运行一下：

package com.mkyong.common;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App
{
    public static void main( String[] args )
    {
    	ApplicationContext context = new ClassPathXmlApplicationContext("SpringBeans.xml");

    	Customer cust = (Customer)context.getBean("CustomerBean");
    	System.out.println(cust);

    }
}

输出：

Customer [

lists=[
1,
Person [address=address 1, age=28, name=mkyong1],
Person [address=address, age=28, name=mkyongList]
],

maps={
key 1=1,
key 2=Person [address=address 1, age=28, name=mkyong1],
key 3=Person [address=address, age=28, name=mkyongMap]
},

pros={admin=admin@nospam.com, support=support@nospam.com},

sets=[
1,
Person [address=address 1, age=28, name=mkyong1],
Person [address=address, age=28, name=mkyongSet]]
]

代码下载地址：http://www.mkyong.com/wp-content/uploads/2010/03/Spring-Collection-Example.zip

翻译自：https://www.mkyong.com/spring/spring-collections-list-set-map-and-properties-example/