spring4笔记----PropertyPlaceholderConfigurer 属性占位符配置器

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/spring
username=root
password=123456
<!-- 
--------PropertyOverrideConfigurer ------------------
dataSource.driverClass=com.mysql.jdbc.Driver
dataSource.jdbcUrl=jdbc:mysql://localhost:3306/spring
dataSource.user=root
dataSource.password=123456



 -->

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.3.xsd">
<!--<bean class="org.springframework.beans.factory.config.PropertyOverrideConfigurer">  -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>dataSource.properties</value>
</list>
</property>
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"
 p:driverClass="${driverClassName}" p:jdbcUrl="${url}" p:user="${username}" p:password="${password}"
/>
</beans>

---

package com.ij34.bean;
import java.sql.*;
import javax.sql.DataSource;

import org.springframework.context.*;
import org.springframework.context.support.*;

public class test {

public static void main(String[] args) throws Exception {
   @SuppressWarnings("resource")
ApplicationContext  ac=new ClassPathXmlApplicationContext("beans.xml");
   DataSource ds=(DataSource) ac.getBean("dataSource");
   Connection conn=ds.getConnection();
   PreparedStatement ps= conn.prepareStatement("insert into news_inf value(null,?,?)");
   ps.setString(1, "加油2017");
   ps.setString(2, "2017,这是挑战与机遇的一年!");
   ps.executeUpdate();
   ps.close();
   conn.close();
}
}