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JavaEE笔记(十一)

Spring beans使用参数占位符(JDBC配置读取示例)

beans.xml配置文件

<?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="db.properties"/>     

        <!-- 占位符 得配置方式-->
        <bean id="dbUtil" class="com.my.util.DBUtil">
        <property name="driverName"  value="${driverName}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}" />
        <property name="pwd" value="${pwd}"/>
        </bean>
 
  <!-- 注册propertyPlaceholderConfigurer对象->
  <bean id="propertyPlaceholderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" >
    <property name="locations">
      <list>
        <value>db.properties</value>
      </list>
    </property>
  </bean> 
   -->
 
 
</beans>           

db.properties 配置文件

driverName=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/jg29
username=root
pwd=root

(# 降低耦合度,符合开闭原则【对拓展开、对修改源码闭】)

JavaEE笔记(十一)