在spring中无法使用util命名空间setter依赖注入注入HashMap对象

Question

我试图使用util命名空间注入HashMap对象但不能为该Object获取HashMap类（LinkedHashMap类名称正在打印。）无法弄清楚为什么会发生这种情况。

我在这个测试中使用Spring jar：

1. spring-beans-5.0.7.RELEASE.jar 
2. spring-context-5.0.7.RELEASE.jar 
3. spring-core-5.0.7.RELEASE.jar 
4. spring-expression-5.0.7.RELEASE.jar 
5. commons-logging-1.1.1.jar 

1. 豆类：

           package com.vitp.pkg1;
   
           import java.util.HashMap;
   
           public class ActualCollections {
   
               private HashMap<String,Integer> student;
   
               public void setStudent(HashMap<String, Integer> student) {
                   this.student = student;
               }
   
               public void displayData()
               {
                    System.out.println("Map data(Student<name,rollnumber>) : ---default is LinkedHashMap And actual is :: "+student.getClass().getName());
                    for(String key : student.keySet())
                    {
                        System.out.println(key+"::"+student.get(key));
                    }
               }
           }

2. 用于测试输出的驱动程序类：

           package com.vitp.start;
   
           import org.springframework.context.ApplicationContext;
           import org.springframework.context.support.ClassPathXmlApplicationContext;
   
           import com.vitp.pkg1.ActualCollections;
           import com.vitp.pkg1.DefaultCollections;
   
           public class ActualCollectionObjectInjectionTest {
   
               public static void main(String... s)
               {
                   ApplicationContext beans = new ClassPathXmlApplicationContext("/com/vitp/resources/particular_collection.xml");
                   ActualCollections pc = (ActualCollections) beans.getBean("pc");
                   pc.displayData();
               }
           }

3. xml配置文件：

           <!--In this case we need to make use of util namespace so will use xsd instate of dtd.-->
   
           <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="pc" class="com.vitp.pkg1.ActualCollections">
                   <!--Set Map attribute with setter injection-->
                   <property name="student">
                       <util:map map-class="java.util.HashMap">
                           <!-- demonstrating various ways on values for entry-->
                           <entry key="Sachin" value="1"/>
                           <!--way2-->               
                           <entry key="Rahul">
                               <value>2</value>
                           </entry>
                           <!--way3-->
                           <entry key="Vinayak" value-ref="three"/>
                           <!--way4-->
                           <entry key="Salman">
                               <ref bean="four"/>
                           </entry>
                       </util:map>
                   </property>
               </bean>
   
               <bean id="three" class="java.lang.Integer">
                   <constructor-arg index="0">
                       <value>3</value>
                   </constructor-arg>
               </bean>
   
               <bean id="four" class="java.lang.Integer">
                   <constructor-arg index="0">
                       <value>4</value>
                   </constructor-arg>
               </bean>
   
           </beans>

结果是：

            Sep 09, 2018 7:17:03 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
            INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@27f8302d: startup date [Sun Sep 09 19:17:03 IST 2018]; root of context hierarchy
            Sep 09, 2018 7:17:03 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
            INFO: Loading XML bean definitions from class path resource [com/vitp/resources/particular_collection.xml]
            Map data(Student<name,rollnumber>) : ---default is LinkedHashMap And actual is :: java.util.LinkedHashMap
            Rahul::2
            Vinayak::3
            Sachin::1
            Salman::4

我期待它应该是HashMap类。

Answer 1

您缺少Map的id属性。如果你为地图添加id，它就可以了。工作代码：

<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="pc" class="com.vitp.pkg1.ActualCollections">
        <property name="student" ref="someId"/>
    </bean>

    <util:map id="someId" map-class="java.util.HashMap">
        <!-- demonstrating various ways on values for entry-->
        <entry key="Sachin" value="1"/>
        <!--way2-->               
        <entry key="Rahul">
            <value>2</value>
        </entry>
        <!--way3-->
        <entry key="Vinayak" value-ref="three"/>
        <!--way4-->
        <entry key="Salman">
            <ref bean="four"/>
        </entry>
    </util:map>

    <bean id="three" class="java.lang.Integer">
        <constructor-arg index="0">
            <value>3</value>
        </constructor-arg>
    </bean>

    <bean id="four" class="java.lang.Integer">
        <constructor-arg index="0">
            <value>4</value>
        </constructor-arg>
    </bean>

</beans>