【Spring实战】—— 7 复杂集合类型的注入

以前讲解了Spring的基本类型和bean引用的注入，接下来学习一下复杂集合类型的注入，例如：List、Set、Map等。

　　对于程序员来讲，掌握多种语言是基本的技能。

　　咱们这里作了一个小例子，程序员们是一个Bean实例，而掌握的编程语言则是放入一个集合类型中进行注入。

　　简单的来讲：

　　List是一种按照序号标识的集合，

　　Set与List类似可是元素不容许重复，

　　Map则是一种自定的键值对，键值均可以是任意的类型。

　　Bean的实现类

public class Programmer { public Programmer(){} //List 与 Set的注入
    private Collection<Language> language; public void setLanguage(Collection<Language> language){ this.language = language; } public void working(){ for(Language lang : language){ System.out.println("working on "+lang.using()); } } //Map的注入
    private Map<String,Language> lang; public void setLang(Map<String,Language> lang){ this.lang = lang; } public void studying(){ for(String key : lang.keySet()){ System.out.print(key+" : "); Language language = lang.get(key); System.out.println("studying on "+language.using()); } } }

　　其余须要的一些接口和实现类

public interface Language { public String using(); }

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public class Java implements Language{ public String using() { return "Java"; } }

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public class Cpp implements Language{ public String using() { return "C++"; } }

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　　Spring的配置文件以下

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean id="java" class="com.spring.test.collector.Java"/>
    <bean id="cpp" class="com.spring.test.collector.Cpp"/>
    <bean id="xingoo" class="com.spring.test.collector.Programmer">
        <property name="language">
            <list>
                <ref bean="java"/>
                <ref bean="cpp"/>
            </list>
        </property>
    </bean>
    <bean id="halo" class="com.spring.test.collector.Programmer">
        <property name="language">
            <set>
                <ref bean="java"/>
            </set>
        </property>
    </bean>
    <bean id="zhang3" class="com.spring.test.collector.Programmer">
        <property name="lang">
            <map>
                <!-- key键为String key-ref键为其余bean的引用 -->
                <!-- value值为String value-ref值为其余bean的引用 -->
                <entry key="java" value-ref="java"/>
                <entry key="cpp" value-ref="cpp"/>
            </map>
        </property>
    </bean>
</beans>

　　获取Bean实例并使用

public class test { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml"); System.out.println("[xingoo]"); Programmer programmer = (Programmer)ctx.getBean("xingoo"); programmer.working(); System.out.println("[halo]"); Programmer programmer1 = (Programmer)ctx.getBean("halo"); programmer1.working(); System.out.println("[zhang3]"); Programmer programmer2 = (Programmer)ctx.getBean("zhang3"); programmer2.studying(); } }

　　执行结果：

[xingoo] working on Java working on C++ [halo] working on Java [zhang3] java : studying on Java cpp : studying on C++