使用Setter方法注入非字符串Map的示例

在这个示例中，我们使用map作为问题的答案，其中答案是Answer和User的组合。在这里，我们将键和值都作为对象使用。Answer有它自己的信息，如answerId，answer和postedDate，User有它自己的信息，如userId，username和emailId。

和之前的示例一样，这是一个论坛的示例，一个问题可以有多个答案。

Question.java

这个类包含三个属性，getter和setter方法以及displayInfo()方法用于显示信息。

package cn.javatiku;  
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<Answer,User> 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<Answer, User>> set=answers.entrySet();  
    Iterator<Entry<Answer, User>> itr=set.iterator();  
    while(itr.hasNext()){  
        Entry<Answer, User> entry=itr.next();  
        Answer ans=entry.getKey();  
        User user=entry.getValue();  
        System.out.println("Answer Information:");  
        System.out.println(ans);  
        System.out.println("Posted By:");  
        System.out.println(user);  
    }  
}  
}  

Answer.java

这个类有三个属性id，answer和postedDate，有构造函数和toString()方法。

package cn.javatiku;  
  
import java.util.Date;  
  
public class Answer {  
private int id;  
private String answer;  
private Date postedDate;  
public Answer() {}  
public Answer(int id, String answer, Date postedDate) {  
    super();  
    this.id = id;  
    this.answer = answer;  
    this.postedDate = postedDate;  
}  
  
public String toString(){  
    return "Id:"+id+" Answer:"+answer+" Posted Date:"+postedDate;  
}  
}  

User.java

这个类有三个属性id，name和email，有构造函数和toString()方法。

package cn.javatiku;  
  
public class User {  
private int id;  
private String name,email;  
public User() {}  
public User(int id, String name, String email) {  
    super();  
    this.id = id;  
    this.name = name;  
    this.email = email;  
}  
  
public String toString(){  
    return "Id:"+id+" Name:"+name+" Email Id:"+email;  
}  
}  

applicationContext.xml

map的entry元素的key-ref和value-ref属性用于定义Map中bean的引用。

<?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="answer1" class="cn.javatiku.Answer">  
<property name="id" value="1"></property>  
<property name="answer" value="Java is a Programming Language"></property>  
<property name="postedDate" value="12/12/2001"></property>  
</bean>  
<bean id="answer2" class="cn.javatiku.Answer">  
<property name="id" value="2"></property>  
<property name="answer" value="Java is a Platform"></property>  
<property name="postedDate" value="12/12/2003"></property>  
</bean>  
  
<bean id="user1" class="cn.javatiku.User">  
<property name="id" value="1"></property>  
<property name="name" value="Arun Kumar"></property>  
<property name="email" value="arun@gmail.com"></property>  
</bean>  
<bean id="user2" class="cn.javatiku.User">  
<property name="id" value="2"></property>  
<property name="name" value="Varun Kumar"></property>  
<property name="email" value="Varun@gmail.com"></property>  
</bean>  
  
<bean id="q" class="cn.javatiku.Question">  
<property name="id" value="1"></property>  
<property name="name" value="What is Java?"></property>  
<property name="answers">  
<map>  
<entry key-ref="answer1" value-ref="user1"></entry>  
<entry key-ref="answer2" value-ref="user2"></entry>  
</map>  
</property>  
</bean>  
  
</beans>  

Test.java

这个类从applicationContext.xml文件中获取bean，并调用displayInfo()方法来显示信息。

package cn.javatiku;  
  
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();  
      
}  
}