Spring学习(八)-----Spring注入值到集合类型的例子

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}]