Spring引用properties文件

    Srping提供了PropertyPlaceholderConfigurer，它是一个容器后处理器，负责读取properties属性文件里的属性值，并将这些属性值设置成Spring配置文件的元数据。

如定义Properties类：

1package com.custle.spring;
2
3/**
4 * Created by admin on 2018/3/2.
5 */
6public class Properties {
7    private String name;
8    private Integer age;
9
10    public String getName() {
11        return name;
12    }
13
14    public void setName(String name) {
15        this.name = name;
16    }
17
18    public Integer getAge() {
19        return age;
20    }
21
22    public void setAge(Integer age) {
23        this.age = age;
24    }
25}

在XML中为Properties类通过读取properties文件获取属性值：

1<?xml version="1.0" encoding="UTF-8"?>
2<beans 
3	xmlns="http://www.springframework.org/schema/beans"
4	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
5	xsi:schemaLocation="http://www.springframework.org/schema/beans
6                                   http://www.springframework.org/schema/beans/spring-beans.xsd">
7	<!--引用MyProperty.properties-->
8	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
9		<property name="location">
10			<value>MyProperty.properties</value>
11		</property>
12	</bean>
13	<bean id="testPro" class="com.custle.spring.Properties">
14		<property name="name" value="${myProperty.name}"/>
15		<property name="age" value="${myProperty.age}"/>
16	</bean>
17</beans>

MyProperty.properties配置文件：

1myProperty.name = propertyName
2myProperty.age = 13

测试程序：

1package com.custle.spring.test;
2
3import com.custle.spring.Properties;
4import org.springframework.context.ApplicationContext;
5import org.springframework.context.support.ClassPathXmlApplicationContext;
6
7/**
8 * Created by admin on 2018/3/2.
9 */
10public class PropertyTest {
11    public static void main(String[] args) {
12        ApplicationContext ac = new ClassPathXmlApplicationContext("spring-property.xml");
13        Properties testPro = ac.getBean("testPro", Properties.class);
14        System.out.println(testPro.getName() + "现在" + testPro.getAge() + " 了");
15    }
16}

控制台输出：

propertyName现在13 了

如果需要读取多个perperties文件的话，将配置文件改为如下方法：

1<!--引用MyProperty.properties-->
2	<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
3		<property name="locations">
4			<list>
5				<value>MyProperty.properties</value>
6				<!--如果有多个配置文件继续列出-->
7			</list>
8		</property>
9	</bean>

在XML中的第二种配置方法：

1<?xml version="1.0" encoding="UTF-8"?>
2<beans
3		xmlns="http://www.springframework.org/schema/beans"
4		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
5		xmlns:context="http://www.springframework.org/schema/context"
6		xsi:schemaLocation="http://www.springframework.org/schema/beans
7                            http://www.springframework.org/schema/beans/spring-beans.xsd
8							http://www.springframework.org/schema/context
9							http://www.springframework.org/schema/context/spring-context.xsd">
10    <!--引用MyProperty.properties文件-->
11    <context:property-placeholder location="MyProperty.properties"/>
12	<bean id="testPro" class="com.custle.spring.Properties">
13		<property name="name" value="${myProperty.name}"/>
14		<property name="age" value="${myProperty.age}"/>
15	</bean>
16	
17</beans>