Spring教程

Setter注入和Map示例

在此示例中,我们使用 map 作为问题的答案,该问题的答案为键,而用户名为值。在这里,我们将键和值对都用作字符串。
像前面的示例一样,它是论坛的示例,其中 一个问题可以有多个答案
Question.java
此类包含三个属性,即getters和setters和displayInfo()方法以显示信息。
package com.lidihuo;
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
map entry 属性用于定义键和值信息。
<?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.lidihuo.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
此类从applicationContext.xml文件获取Bean并调用displayInfo()方法。
package com.lidihuo;
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();
    
}
}
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