Spring-注入参数详解-[通过util命名空间简化集合类型的配置]

小小工匠

发布于 2021-08-16 16:28:30

4310

发布于 2021-08-16 16:28:30

文章被收录于专栏：小工匠聊架构

概述

如果希望配置一个集合类型的Bean，而非一个集合类型的属性，则可以通过util命名空间进行配置。

在spring的配置文件中util命名空间类似于java.util包类对应，util命名空间提供了集合相关的配置，在使用命名空间前要导入util命名空间。

步骤

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

声明命名空间和schema

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
    -- 命名空间 -->
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd
    
    http://www.springframework.org/schema/util 
    http://www.springframework.org/schema/util/spring-util.xsd">

.....

beans>

配置Bean

配置一个Map

POJO类

package com.xgj.ioc.inject.construct.utilSchema;

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() {

        Map map = pets.getPetMap();

        for (Map.Entry entry : map.entrySet()) {

            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "
                    + entry.getValue());

        }
    }

}

POJO类

package com.xgj.ioc.inject.construct.utilSchema;

import java.util.Map;

public class Pets {

    private Map petMap;

    public Map getPetMap() {
        return petMap;
    }

    public void setPetMap(Map petMap) {
        this.petMap = petMap;
    }

}

配置文件

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"

    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/util 
    http://www.springframework.org/schema/util/spring-util.xsd">


    <bean id="petShop" class="com.xgj.ioc.inject.construct.utilSchema.PetShop">
        <property name="pets" ref="pets" />
    bean>


    
    <bean id="pets" class="com.xgj.ioc.inject.construct.utilSchema.Pets">
        <property name="petMap">
            <util:map  map-class="java.util.HashMap">
                <entry key="101" value="dog" />
                <entry key="103" value="wolf" />
                <entry key="105" value="bird" />
            util:map>
        property>
    bean>

beans>

测试类

package com.xgj.ioc.inject.construct.utilSchema;

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

public class UtilSchemaTest {

    public static void main(String[] args) {

        ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "classpath:com/xgj/ioc/inject/construct/utilSchema/beans.xml");

        PetShop petShop = ctx.getBean("petShop", PetShop.class);

        petShop.petsInfo_Map();

    }
}

运行结果

支持key-type和value-type属性，指定Map的键和值的类型

class="java.util.HashMap" 
            key-type="java.lang.Integer" 
            value-type="java.lang.String">
                "101" value="dog" />
                "103" value="wolf" />
                "105" value="bird" />

和支持value-type属性，指定集合中的值的类型

Map、Set、List、Properties实例汇总

POJO类

package com.xgj.ioc.inject.construct.utilSchema;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

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() {

        Map map = pets.getPetMap();

        for (Map.Entry entry : map.entrySet()) {

            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "
                    + entry.getValue());
        }
    }

    /**
     * 
     * 
     * @Title: petsInfo
     * 
     * @Description: 获取容器注入的List，遍历输出
     * 
     * 
     * @return: void
     */
    public void petsInfo_List() {
        for (int i = 0; i < pets.getPetList().size(); i++) {
            System.out.println("PetShop has " + pets.getPetList().get(i));
        }
    }

    /**
     * 
     * 
     * @Title: petsInfo
     * 
     * @Description: 获取注入的set,遍历输出
     * 
     * 
     * @return: void
     */
    public void petsInfo_Set() {
        Set set = pets.getPetSet();
        Iterator it = set.iterator();
        while (it.hasNext()) {
            System.out.println("PetShop has " + it.next());
        }
    }

    /**
     * 
     * 
     * @Title: petsInfo
     * 
     * @Description: 获取容器注入的Properties，遍历输出
     * 
     * 
     * @return: void
     */
    public void petsInfo_Properties() {

        Map map = pets.getPetProperties();

        for (Map.Entry entry : map.entrySet()) {

            System.out.println("编号Key = " + entry.getKey() + ",品种Value = "
                    + entry.getValue());

        }
    }
}

POJO类

package com.xgj.ioc.inject.construct.utilSchema;

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

public class Pets {

    private Map petMap;

    private List petList;

    private Set petSet;

    private Properties petProperties;

    public Properties getPetProperties() {
        return petProperties;
    }

    public void setPetProperties(Properties petProperties) {
        this.petProperties = petProperties;
    }

    public Set getPetSet() {
        return petSet;
    }

    public void setPetSet(Set petSet) {
        this.petSet = petSet;
    }

    public List getPetList() {
        return petList;
    }

    public void setPetList(List petList) {
        this.petList = petList;
    }

    public Map getPetMap() {
        return petMap;
    }

    public void setPetMap(Map petMap) {
        this.petMap = petMap;
    }

}

配置文件

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"

    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/util 
    http://www.springframework.org/schema/util/spring-util.xsd">


    <bean id="petShop" class="com.xgj.ioc.inject.construct.utilSchema.PetShop">
        <property name="pets" ref="pets" />
    bean>

 
 
    <bean id="pets" class="com.xgj.ioc.inject.construct.utilSchema.Pets">
        <property name="petMap" ref="petMap"/>
        <property name="petList" ref="petList"/>
        <property name="petSet" ref="petSet"/>
        <property name="petProperties" ref="petProperties"/>
    bean>


    
    <util:map id="petMap" map-class="java.util.HashMap">
        <entry key="101" value="dog" />
        <entry key="103" value="wolf" />
        <entry key="105" value="bird" />
    util:map>

    
    <util:list id="petList" list-class="java.util.ArrayList" value-type="java.lang.String">
        <value>DOGvalue>
        <value>CATvalue>
        <value>BIRDvalue>
    util:list>

     
    <util:set id="petSet" set-class="java.util.HashSet" value-type="java.lang.String">
        <value>牛value>
        <value>马value>
        <value>狗value>
    util:set>


    
    <util:properties id="petProperties">
            <prop key="151">PIGprop>
            <prop key="153">PINGUINprop>
    util:properties>




    


beans>

测试类

package com.xgj.ioc.inject.construct.utilSchema;

import org.apache.log4j.Logger;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UtilSchemaTest {

    static Logger logger = Logger.getLogger(UtilSchemaTest.class);

    public static void main(String[] args) {

        ApplicationContext ctx = new ClassPathXmlApplicationContext(
                "classpath:com/xgj/ioc/inject/construct/utilSchema/beans.xml");

        PetShop petShop = ctx.getBean("petShop", PetShop.class);

        logger.info("---------------Map--------------------");
        petShop.petsInfo_Map();

        logger.info("---------------List--------------------");
        petShop.petsInfo_List();

        logger.info("---------------Set--------------------");
        petShop.petsInfo_Set();

        logger.info("---------------Properties--------------------");
        petShop.petsInfo_Properties();

    }
}

运行结果：