Spring屬性注入（從外部屬性檔案注入）

aplicationContext.xml如下：

<?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:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:util="http://www.springframework.org/schema/util"
	   xsi:schemaLocation="http://www.springframework.org/schema/beans  
                        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd   
                        http://www.springframework.org/schema/context   
                        http://www.springframework.org/schema/context/spring-context-3.0.xsd 
                        http://www.springframework.org/schema/tx
                        http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
                        http://www.springframework.org/schema/util 
                        http://www.springframework.org/schema/util/spring-util-3.0.xsd"
                        default-lazy-init="false">
			
	<context:annotation-config />
	<context:component-scan base-package="com"></context:component-scan>
	<!--===================================================================== -->
	<!-- 配置外部變量檔案 -->
	<!--===================================================================== -->
	<util:properties id="propertyConfigurer" location="classpath:springProject.properties"/>
	<context:property-placeholder properties-ref="propertyConfigurer" />
	
	<import resource="applicationContext-quartz.xml"/>
	

	<bean id="helloService" class="com.spring.test.HelloService">
		<property name="name">
			<value>${name}</value>
		</property>
		<property name="age">
			<value>${age}</value>
		</property>
	</bean>
</beans>      

helloService中的這種方式是屬性注入的一種方式，那麼另外一種方式就是在類中使用@Value注解。

比如：

package com.spring.test.propertyinject;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Student {
	@Value("${name}")
	private String name;
	@Value("${age}")
	private int age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "Student [name=" + name + ", age=" + age + "]";
	}
	
}