Spring 集合注入

　　Spring注入是spring框架的核心思想之一。在实际的开发中，我们经常会遇见这样一些类的注入，这些类中包含一些集合作为类的属性，那么要怎样想类中的集合注入数据呢？本文通过一个简单的示例向大家介绍一下如何在Spring中完成集合信息的注入。

　　首先建立一个最基本的web项目：springSetInjection。

　　

　　干脆利落直接点击Finish，生成springSetInjection项目，框架如下图：

　　首先向项目中引入Spring开发必要的jar包，将相关包放在lib目录下：

　　然后在src目录下新建两个package:com.unionpay.beans 和 com.unionpay.controller。从包名就可以看出，这两个package的作用：一个用来装Bean类，一个用来装Controller类。

　　下面在beans包里面新建两个类：Person.java 和 Injection.java

　　Person.java

package com.unionpay.beans;

public class Person {
    
    private String username;
    private int age;
    private String address;
    
    
    public Person(String username, int age, String address) {
        super();
        this.username = username;
        this.age = age;
        this.address = address;
    }

    public Person() {
        super();
        // TODO Auto-generated constructor stub
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Person [username=" + username + ", age=" + age + ", address=" + address + "]";
    }
}

　　Injection.java

package com.unionpay.beans;

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

public class Injection {
    
    private List<Object> lists;
    private Set<Object> sets;
    private Map<Object,Object> maps;
    private Properties properties;
    
    public Injection(List<Object> lists, Set<Object> sets, Map<Object, Object> maps, Properties properties) {
        super();
        this.lists = lists;
        this.sets = sets;
        this.maps = maps;
        this.properties = properties;
    }

    public Injection() {
        super();
        // TODO Auto-generated constructor stub
    }

    public List<Object> getLists() {
        return lists;
    }
    
    public void setLists(List<Object> lists) {
        this.lists = lists;
    }

    public Set<Object> getSets() {
        return sets;
    }

    public void setSets(Set<Object> sets) {
        this.sets = sets;
    }

    public Map<Object, Object> getMaps() {
        return maps;
    }

    public void setMaps(Map<Object, Object> maps) {
        this.maps = maps;
    }

    public Properties getProperties() {
        return properties;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }
    
    public String listInfo(){
        return lists.toString();
    }
    
    public String setInfo(){
        return sets.toString();
    }
    
    public String mapInfo(){
        return maps.toString();
    }
    
    public String propertiesInfo(){
        return properties.toString();
    }
}

　　然后在src目录下新建spring配置文件：config-beans.xml

　　config-beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="injectionBean" class="com.unionpay.beans.Injection">
        <property name="lists">
            <list>
                <value>data1</value>
                <ref bean="person" />
                <bean class="com.unionpay.beans.Person">
                    <property name="username" value="jianxianwch"></property>
                    <property name="age" value="27"></property>
                    <property name="address" value="Shanghai"></property>
                </bean>
            </list>
        </property>

        <property name="sets">
            <set>
                <value>data1</value>
                <ref bean="person" />
                <bean class="com.unionpay.beans.Person">
                    <property name="username" value="jianxianwch"></property>
                    <property name="age" value="27"></property>
                    <property name="address" value="Shanghai"></property>
                </bean>
            </set>
        </property>

        <property name="maps">
            <map>
                <entry key="key 1" value="data1"></entry>
                <entry key="key 2" value-ref="person"></entry>
                <entry key="key 3">
                    <bean class="com.unionpay.beans.Person">
                        <property name="username" value="jianxianwch"></property>
                        <property name="age" value="27"></property>
                        <property name="address" value="Shanghai"></property>
                    </bean>
                </entry>
            </map>
        </property>
        
        <property name="properties">
            <props>
                <prop key="username">admin</prop>
                <prop key="password">admin</prop>
            </props>
        </property>
    </bean>

    <bean id="person" class="com.unionpay.beans.Person">
        <constructor-arg name="username" value="jxwch"></constructor-arg>
        <constructor-arg name="age" value="27"></constructor-arg>
        <constructor-arg name="address" value="Anhui"></constructor-arg>
    </bean>
</beans>

　　从配置文件中，我们可以看出将lists，sets，maps 和properties注入到了injectionBean中。Spring支持这四种集合的注入。

　　然后在controller包中建立InjectionController.java

package com.unionpay.controller;

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

import com.unionpay.beans.Injection;

public class InjectionController {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        ApplicationContext context = new ClassPathXmlApplicationContext("config-beans.xml");
        
        Injection injection = (Injection) context.getBean("injectionBean");
        
        System.out.println(injection.getLists());
        System.out.println(injection.getSets());
        System.out.println(injection.getMaps());
        System.out.println(injection.getProperties());
    }

}

　　到目前为止，项目建立完成。右键InjectionController.java文件，选择Run As -->Java Application。终端打印出如下信息：

　　从终端打印信息中可以看见刚才注入的四种集合的数据，示例成功。

　　源码下载：test.zip