Java Source World: Spring Framework - Setter Injection with Map Example

In this example, we are using map as the answer for a question that have answer as the key and username as the value. Here, we are using key and value pair both as a string.

Like previous examples, it is the example of forum where one question can have multiple answers.

Question.java

This class contains three properties, getters & setters and displayInfo() method to display the information.

    package com.springexample; 

    import java.util.Iterator; 

    import java.util.Map; 

    import java.util.Set; 

    import java.util.Map.Entry;       

    public class Question { 

    private int id; 

    private String name; 

    private Map<String,String> answers; 

     

    //getters and setters 

     

    public void displayInfo(){ 

        System.out.println("question id:"+id); 

        System.out.println("question name:"+name); 

        System.out.println("Answers...."); 

        Set<Entry<String, String>> set=answers.entrySet(); 

        Iterator<Entry<String, String>> itr=set.iterator(); 

        while(itr.hasNext()){ 

            Entry<String,String> entry=itr.next(); 

            System.out.println("Answer:"+entry.getKey()+" Posted By:"+entry.getValue()); 

        } 

    } 

    } 

applicationContext.xml

The entry attribute of map is used to define the key and value information.

    <?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:p="http://www.springframework.org/schema/p" 

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

    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">       

    <bean id="q" class="com.springexample.Question"> 

    <property name="id" value="1"></property> 

    <property name="name" value="What is Java?"></property> 

    <property name="answers"> 

    <map>  

    <entry key="Java is a programming language"  value="Sonoo Jaiswal"></entry> 

    <entry key="Java is a Platform" value="Sachin Yadav"></entry> 

    </map> 

    </property> 

    </bean>       

    </beans> 

Test.java

This class gets the bean from the applicationContext.xml file and calls the displayInfo() method.

    package com.springexample; 

    import org.springframework.beans.factory.BeanFactory; 

    import org.springframework.beans.factory.xml.XmlBeanFactory; 

    import org.springframework.core.io.ClassPathResource; 

    import org.springframework.core.io.Resource;       

    public class Test { 

    public static void main(String[] args) { 

        Resource r=new ClassPathResource("applicationContext.xml"); 

        BeanFactory factory=new XmlBeanFactory(r);           

        Question q=(Question)factory.getBean("q"); 

        q.displayInfo();           

    } 

    }   

Also Read: Constructor Injection with Map