Spring-注入参数详解-[集合类型属性]

概述

java.util包中的集合类型是最常用的结构数据类型，主要包括List、Set、Map、Properties。

Spring为这些集合类型属性提供了专属的配置标签

常用集合

代码已托管到Github—> https://github.com/yangshangwei/SpringMaster

Set

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.set;import java.util.Iterator;import java.util.Set;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取注入的set,遍历输出     *      *      * @return: void     */    public void petsInfo() {        Set<Object> set = pets.getSet();        Iterator<Object> it = set.iterator();        while (it.hasNext()) {            System.out.println("PetShop has " + it.next());        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.set;import java.util.HashSet;import java.util.Set;public class Pets {    private Set set = new HashSet();    public Set getSet() {        return set;    }    public void setSet(Set set) {        this.set = set;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <bean id="pets" class="com.xgj.ioc.inject.construct.jihe.set.Pets">        <property name="set">            <set>                <value>bear</value>                <value>dog</value>                <value>cat</value>                <value>snake</value>                <value>pig</value>            </set>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.set.PetShop">        <property name="pets" ref="pets"/>    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.set;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectSetTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/set/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果

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List

List属性既可以通过注入字符串，也可以通过注入容器中其他的Bean

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.list;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取容器注入的List，遍历输出     *      *      * @return: void     */    public void petsInfo() {        for (int i = 0; i < pets.getPetsList().size(); i++) {            System.out.println("PetShop has " + pets.getPetsList().get(i));        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.list;import java.util.ArrayList;import java.util.List;public class Pets {    private List petsList = new ArrayList();    public List getPetsList() {        return petsList;    }    public void setPetsList(List petsList) {        this.petsList = petsList;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <bean id="pets" class="com.xgj.ioc.inject.construct.jihe.list.Pets">        <property name="petsList">            <list>                <value>dog</value>                <value>cat</value>                <value>bear</value>                <value>rabbit</value>                <value>bird</value>            </list>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.list.PetShop">        <property name="pets">            <ref bean="pets"/>        </property>    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.list;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectListTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/list/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果

假设一个属性类型可以通过字符串字面值进行配置，那么该类型对应的数组类型的属性比入String[],int[]也可以采用<list>方式进行配置.

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Map

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.map;import java.util.Map;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取容器注入的Map，遍历输出     *      *      * @return: void     */    public void petsInfo() {        Map<Object, Object> map = pets.getMap();        for (Map.Entry<Object, Object> entry : map.entrySet()) {            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "                    + entry.getValue());        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.map;import java.util.HashMap;import java.util.Map;public class Pets {    private Map map = new HashMap();    public Map getMap() {        return map;    }    public void setMap(Map map) {        this.map = map;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <bean id="pets" class="com.xgj.ioc.inject.construct.jihe.map.Pets">        <property name="map">            <map>                <entry>                    <key>                        <value>135</value>                    </key>                    <value>cat</value>                </entry>                <entry>                    <key>                        <value>137</value>                    </key>                    <value>bird</value>                </entry>                <entry>                    <key>                        <value>139</value>                    </key>                    <value>dog</value>                </entry>            </map>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.map.PetShop">        <property name="pets" ref="pets" />    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.map;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectMapTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/map/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果：

如果Map元素的key和value都是对象，这可以采用以下配置方式

<entry>    <key>        <ref bean="keyBbean"/>    </key>    <ref bean="valueBean"></entry>

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Properties

Propertites键值对可以看做Map类型的特例， Map的键值对可以是任何类型，Properties的键值对只能是字符串，因此配置简单一些，注意Value的配置没有<value>子元素标签

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.properties;import java.util.Map;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取容器注入的Map，遍历输出     *      *      * @return: void     */    public void petsInfo() {        Map<Object, Object> map = pets.getProperties();        for (Map.Entry<Object, Object> entry : map.entrySet()) {            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "                    + entry.getValue());        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.properties;import java.util.Properties;public class Pets {    private Properties properties;    public Properties getProperties() {        return properties;    }    public void setProperties(Properties properties) {        this.properties = properties;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <bean id="pets" class="com.xgj.ioc.inject.construct.jihe.properties.Pets">        <property name="properties">            <props>                <prop key="101">cat</prop>                <prop key="103">dog</prop>                <prop key="105">bird</prop>            </props>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.properties.PetShop">        <property name="pets" ref="pets" />    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.properties;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectPropertiesTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/properties/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果

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强类型集合

Java5.0提供了强类型集合的新功能，允许为集合元素指定特定类型。

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.strongType;import java.util.Map;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取容器注入的Map，遍历输出     *      *      * @return: void     */    public void petsInfo() {        Map<Integer, String> map = pets.getMap();        for (Map.Entry<Integer, String> entry : map.entrySet()) {            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "                    + entry.getValue());        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.strongType;import java.util.HashMap;import java.util.Map;public class Pets {    private Map<Integer, String> map = new HashMap<Integer, String>();    public Map<Integer, String> getMap() {        return map;    }    public void setMap(Map<Integer, String> map) {        this.map = map;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <bean id="pets" class="com.xgj.ioc.inject.construct.jihe.strongType.Pets">        <property name="map">            <map>                <entry>                    <key>                        <!-- 为Integer提供值,spring在设置值时，会转换为定义的Integer类型 -->                        <value>111</value>                    </key>                    <value>cat</value>                </entry>                <entry>                    <key>                        <value>113</value>                    </key>                    <value>bird</value>                </entry>                <entry>                    <key>                        <value>115</value>                    </key>                    <value>dog</value>                </entry>            </map>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.strongType.PetShop">        <property name="pets" ref="pets" />    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.strongType;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectStrongTypeTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/strongType/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果

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集合合并

Spring支持集合合并的功能，允许子bean继承父bean的同名属性集合元素，并将子bean和父bean中配置的集合属性组合并起来作为最终的bean的属性值。

实例

POJO类

package com.xgj.ioc.inject.construct.jihe.merge;import java.util.Map;public class PetShop {    private Pets pets;    public void setPets(Pets pets) {        this.pets = pets;    }    /**     *      *      * @Title: petsInfo     *      * @Description: 获取容器注入的Map，遍历输出     *      *      * @return: void     */    public void petsInfo() {        Map<Integer, String> map = pets.getMap();        for (Map.Entry<Integer, String> entry : map.entrySet()) {            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "                    + entry.getValue());        }    }}

POJO类

package com.xgj.ioc.inject.construct.jihe.merge;import java.util.HashMap;import java.util.Map;public class Pets {    private Map<Integer, String> map = new HashMap<Integer, String>();    public Map<Integer, String> getMap() {        return map;    }    public void setMap(Map<Integer, String> map) {        this.map = map;    }}

配置文件

<?xml version="1.0" encoding="UTF-8"?><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.xsd">    <!-- 父Bean abstract="true" -->    <bean id="parentPets"   abstract="true" class="com.xgj.ioc.inject.construct.jihe.merge.Pets">        <property name="map">            <map>                <entry>                    <key>                        <!-- 为Integer提供值,spring在设置值时，会转换为定义的Integer类型 -->                        <value>111</value>                    </key>                    <value>cat</value>                </entry>                <entry>                    <key>                        <value>113</value>                    </key>                    <value>bird</value>                </entry>                <entry>                    <key>                        <value>115</value>                    </key>                    <value>dog</value>                </entry>            </map>        </property>    </bean>    <bean id="pets" parent="parentPets"> <!-- 指定父Bean -->        <property name="map">            <!-- 设置merge="true" 和父bean的同名集合属性合并 -->            <map merge="true">                 <entry>                    <key>                        <value>117</value>                    </key>                    <value>monkey</value>                </entry>            </map>        </property>    </bean>    <bean id="petShop" class="com.xgj.ioc.inject.construct.jihe.merge.PetShop">        <property name="pets" ref="pets" />    </bean></beans>

测试类

package com.xgj.ioc.inject.construct.jihe.merge;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class InjectStrongTypeTest {    public static void main(String[] args) {        ApplicationContext ctx = new ClassPathXmlApplicationContext(                "classpath:com/xgj/ioc/inject/construct/jihe/merge/beans.xml");        PetShop shop = ctx.getBean("petShop", PetShop.class);        shop.petsInfo();    }}

运行结果

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