1、一个简单的Demo

1.1、创建conf.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"><beans>    <bean id="propertyConfigurer"  class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">        <!--         使用location属性定义单个配置文件        <property name="location">            <value>classpath:/com/zsw/config/jdbc.properties</value>        </property>         -->    <!-- 使用locations属性定义多个配置文件 -->  <property name="locations">     <list>        <value>classpath:/com/zsw/config/jdbc.properties</value>     </list>  </property>     </bean>    <bean id="dataSource"  class="org.springframework.jdbc.datasource.DriverManagerDataSource">        <property name="url">            <value>${database.url}</value>        </property>        <property name="driverClassName">            <value>${database.driver}</value>        </property>        <property name="username">            <value>${database.user}</value>        </property>        <property name="password">            <value>${database.password}</value>        </property>    </bean></beans>

1.2.创建jdbc.properties文件

database.driver=com.mysql.jdbc.Driver

database.url=jdbc:mysql://localhost:3306/right?useUnicode=true&autoReconnect=true&characterEncoding=UTF-8database.user=rootdatabase.password=rootjdbc.pool.c3p0.acquire_increment=2jdbc.pool.c3p0.max_size=20jdbc.pool.c3p0.min_size=2jdbc.pool.c3p0.preferred_test_query='SELECT 1'jdbc.pool.c3p0.idle_connection_test_period=18000jdbc.pool.c3p0.max_idle_time=25000

1.3.创建Config.java

package com.zsw.config;

import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;import org.springframework.beans.factory.xml.XmlBeanFactory;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import org.springframework.core.io.FileSystemResource;import org.springframework.jdbc.datasource.DriverManagerDataSource;public class Config {      public static void main(String[] args) {          XmlBeanFactory factory = new XmlBeanFactory(new FileSystemResource("src/com/zsw/config/conf.xml"));         // 如果要在BeanFactory中使用，bean factory post-processor必须手动运行:         PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();         cfg.setLocation(new FileSystemResource("src/com/zsw/config/jdbc.properties"));         cfg.postProcessBeanFactory(factory);         DriverManagerDataSource dataSource = (DriverManagerDataSource) factory.getBean("dataSource");//         System.out.println(dataSource.getDriverClassName());                           System.out.println(dataSource.getUsername());         // 注意，ApplicationContext能够自动辨认和应用在其上部署的实现了BeanFactoryPostProcessor的bean。这就意味着，当使用ApplicationContext的时候应用PropertyPlaceholderConfigurer会非常的方便。由于这个原因，建议想要使用这个或者其他bean         // factory postprocessor的用户使用ApplicationContext代替BeanFactroy。         ApplicationContext context = new ClassPathXmlApplicationContext("com/zsw/config/conf.xml");         DriverManagerDataSource dataSource2 = (DriverManagerDataSource) context.getBean("dataSource");         System.out.println(dataSource2.getUsername());     } }

 

2.Spring中PropertyPlaceholderConfigurer多种配置方式

2.1配置单个Properties文件

<bean id="propertyConfigurerForAnalysis" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

    <property name="location">        <value>classpath:/spring/include/dbQuery.properties</value>    </property></bean>

其中classpath是引用src目录下的文件写法。

2.2 当存在多个Properties文件时，配置就需使用locations了：

    
         
     
             
      
                 
       
        classpath:/spring/include/jdbc-parms.properties
                 
       
        classpath:/spring/include/base-config.properties
               
          
     
    

 

2.3、接下来我们要使用多个PropertyPlaceholderConfigurer来分散配置，达到整合多工程下的多个分散的Properties 文件，其配置如下：

<bean id="propertyConfigurerForProject1" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

    <property name="order" value="1" />    <property name="ignoreUnresolvablePlaceholders" value="true" />    <property name="location">       <value>classpath:/spring/include/dbQuery.properties</value>    </property></bean>

 

<bean id="propertyConfigurerForProject2" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

    <property name="order" value="2" />    <property name="ignoreUnresolvablePlaceholders" value="true" />    <property name="locations">      <list>        <value>classpath:/spring/include/jdbc-parms.properties</value>        <value>classpath:/spring/include/base-config.properties</value>      </list>    </property></bean>

 

其中order属性代表其加载顺序，而ignoreUnresolvablePlaceholders为是否忽略不可解析的 Placeholder，如配置了多个PropertyPlaceholderConfigurer，则需设置为true