之前讲解了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。
对于程序员来说，掌握多种语言是基本的技能。
我们这里做了一个小例子，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。
简单的来说：
List是一种按照序号标识的集合，
Set与List相似但是元素不允许重复，
Map则是一种自定的键值对，键值都可以是任意的类型。
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());
}
}
}其他需要的一些接口和实现类
public interface Language {
public String using();
}public class Java implements Language{
public String using() {
return "Java";
}
}public class Cpp implements Language{
public String using() {
return "C++";
}
}Spring的配置文件如下
<?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键为其他bean的引用 -->
<!-- value值为String value-ref值为其他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++