spring中的PropertyPlaceholderConfigurer访问properties文件配置

素颜马尾好姑娘i 2022-09-24 08:27 154阅读 0赞

Spring的框架中提供了一个类： org.springframework.beans.factory.config.PropertyPlaceholderConfigurer。这个类，可以将一些经常需要改动的配置如用户名密码等，移至.properties文件中，而.properties文件可以作为客户根据需求，自定义一些相关的参数。

来看一个spring配置C3P0连接池的例子：

**applicationContext.xml**

<?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"  
        xmlns:context="http://www.springframework.org/schema/context"  
        xmlns:aop="http://www.springframework.org/schema/aop"  
        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/aop   
            http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">  
          
        <bean id="config" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">  
    
     <property name="location">  
                    <value>classpath:jdbc.properties</value>  
            </property>  
    
            <property name="locations">  
                <list>  
                    <value>classpath:jdbc.properties</value>  
    <value>classpath:xxx.properties</value>
    <value>classpath:xxx.properties</value>  
                </list>  
            </property>  
        </bean>  
          
          <bean id="comboPooledDataSourceID" class="com.mchange.v2.c3p0.ComboPooledDataSource"> 
          <property name="driverClass" value="${driverClassName}"/>
          <property name="jdbcUrl" value="${url}"/>
          <property name="user" value="${username}"/>
          <property name="password" value="${password}"/>
          </bean>
     
    </beans>

**jdbc.properties**

driverClassName=com.mysql.jdbc.Driver
    url=jdbc\:mysql\://localhost\:3306/test
    username=root
    password=root