下面例子向您展示Spring如何注入值到集合类型(List, Set, Map, and Properties)。 支持4个主要的集合类型：
- List – <list/>
- Set – <set/>
- Map – <map/>
- Properties – <props/>
Spring beans
一个Customer对象，有四个集合属性。
package com.yiibai.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;
//...
}
在bean配置文件中不同的代码片段用来声明集合。
1. List示例
<property name="lists"> <list> <value>1</value> <ref bean="PersonBean" /> <bean class="com.yiibai.common.Person"> <property name="name" value="yiibaiList" /> <property name="address" value="Hainan" /> <property name="age" value="28" /> </bean> </list> </property>
2. Set示例
<property name="sets"> <set> <value>1</value> <ref bean="PersonBean" /> <bean class="com.yiibai.common.Person"> <property name="name" value="yiibaiSet" /> <property name="address" value="Hainan" /> <property name="age" value="28" /> </bean> </set> </property>
3. Map示例
<property name="maps"> <map> <entry key="Key 1" value="1" /> <entry key="Key 2" value-ref="PersonBean" /> <entry key="Key 3"> <bean class="com.yiibai.common.Person"> <property name="name" value="yiibaiMap" /> <property name="address" value="Hainan" /> <property name="age" value="28" /> </bean> </entry> </map> </property>
4. Properties示例
<property name="pros"> <props> <prop key="admin">admin@yiibai.com</prop> <prop key="support">support@yiibai.com</prop> </props> </property>
Spring完整的 bean 配置文件。
<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.yiibai.common.Customer"> <!-- java.util.List --> <property name="lists"> <list> <value>1</value> <ref bean="PersonBean" /> <bean class="com.yiibai.common.Person"> <property name="name" value="yiibaiList" /> <property name="address" value="Hainan Haikou" /> <property name="age" value="28" /> </bean> </list> </property> <!-- java.util.Set --> <property name="sets"> <set> <value>1</value> <ref bean="PersonBean" /> <bean class="com.yiibai.common.Person"> <property name="name" value="yiibaiSet" /> <property name="address" value="Hainan Haikou" /> <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.yiibai.common.Person"> <property name="name" value="yiibaiMap" /> <property name="address" value="Hainan Haikou" /> <property name="age" value="28" /> </bean> </entry> </map> </property> <!-- java.util.Properties --> <property name="pros"> <props> <prop key="admin">admin@yiibai.com</prop> <prop key="support">support@yiibai.com</prop> </props> </property> </bean> <bean id="PersonBean" class="com.yiibai.common.Person"> <property name="name" value="yiibai1" /> <property name="address" value="Hainan Haikou 1" /> <property name="age" value="28" /> </bean> </beans>
执行程序
package com.yiibai.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("applicationContext.xml");
Customer cust = (Customer)context.getBean("CustomerBean");
System.out.println(cust);
}
}
输出
Customer [lists=[1, com.yiibai.common.Person@4e4ee70b, com.yiibai.common.Person@1e1867d2], sets=[1, com.yiibai.common.Person@4e4ee70b, com.yiibai.common.Person@52f644b4], maps={Key 1=1, Key 2=com.yiibai.common.Person@4e4ee70b, Key 3=com.yiibai.common.Person@54481b6d}, pros={admin=admin@yiibai.com, support=support@yiibai.com}]
