Spring基础：快速入门spring（6）：properties文件方式的值注入

上一篇文章里我们学习了普通的值得注入, 在spring的配置文件里设定value即可轻松的将值注入到程序当中，但是这种方式依然Hardcoding的感觉太强，在这篇文章中我们将学习如何使用property文件进行注入值的操作。

定义注入对象的get/set方法

向Student类里面加入name和country两个字段并生成get/set方法(Eclipse右键菜单/IntelliJ的Alt+Insert均可自动生成)

package com.liumiao.demo.spring;public class Student implements Person {    private String name;    private String country;    public String getName() {        return name;    }    public void setName(String name) {        System.out.println("Student: set method: SetName:"+name);        this.name = name;    }    public String getCountry() {        return country;    }    public void setCountry(String country) {        System.out.println("Student: set method: SetCountry:"+country);        this.country = country;    }    private TeachingService teachingService;    public Student(){        System.out.println("Student Default construct is called...");    }    public void setTeachingService(TeachingService service){        teachingService=service;    }    @Override    public String sayhello(){        return "Hello, I am a student.";    }    @Override    public String provideTeachingService(){        return "I teach how to study...";    }}

设定property文件

设定person.properties文件，路径和spring的配置文件同一目录，详细内容如下
person.name=liumiao.cn
person.country=ChinaPRC

配置spring设定文件

如下修改配置文件, 注意如下事项

注意事项 详细 No.1 context:property-placeholder装载properties文件 No.2 使用${key名称}方式设到value中取代Hardcoding No.3 key名称需要与properties文件中的键值对相匹配

<?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"       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">    <context:property-placeholder location="classpath:com/liumiao/demo/spring/Person.properties" />    <bean id="thePerson" class="com.liumiao.demo.spring.Student">        <property name="teachingService" ref="theService"></property>        <property name="name" value="${person.name}" />        <property name="country" value="${person.country}" />    </bean>    <bean id="theService" class="com.liumiao.demo.spring.SwimmingTeachingService">    </bean></beans>

修改TestDemo

package com.liumiao.demo.spring;import com.liumiao.demo.spring.Person;import org.springframework.context.support.ClassPathXmlApplicationContext;public class TestDemo {    public TestDemo() {    }    public static void main(String[] args) {        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:com/liumiao/demo/spring/spring-cfg.xml");        Student person = (Student) context.getBean("thePerson", Person.class);        System.out.println(person.sayhello());        System.out.println(person.provideTeachingService());        System.out.println(person.getCountry());        System.out.println(person.getName());        context.close();    }}

执行结果

TestDemo无需修改可以直接确认结果。

十一月 26, 2016 9:59:57 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@25f38edc: startup date [Sat Nov 26 21:59:57 CST 2016]; root of context hierarchy十一月 26, 2016 9:59:57 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [com/liumiao/demo/spring/spring-cfg.xml]十一月 26, 2016 9:59:58 下午 org.springframework.context.support.PropertySourcesPlaceholderConfigurer loadProperties信息: Loading properties file from class path resource [com/liumiao/demo/spring/Person.properties]Student Default construct is called...Student: set method: SetName:liumiao.cnStudent: set method: SetCountry:ChinaPRCHello, I am a student.十一月 26, 2016 9:59:58 下午 org.springframework.context.support.ClassPathXmlApplicationContext doCloseI teach how to study...信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@25f38edc: startup date [Sat Nov 26 21:59:57 CST 2016]; root of context hierarchyChinaPRCliumiao.cn

这样通过修改properties文件就可以动态修改注入的值了