通过获取配置文件的方式获取dataSource

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=123456

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
    
    <import resource="xmlfolder/app1.xml" />
    <import resource="xmlfolder/innerbean.xml" />
    <import resource="xmlfolder/singleton.xml" />
    <import resource="xmlfolder/annotation.xml" />
    <import resource="xmlfolder/gather.xml" />
    <import resource="xmlfolder/date.xml" />
    <import resource="xmlfolder/db.xml" />
</beans>    

<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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
    
　　<!--用于加载db.properties配置文件，否则下面的$ 无法使用 -->
    <bean
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location">
            <value>db.properties</value>
        </property>
    </bean>
    
    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="${jdbc.driverClassName}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>
</beans>    

package com.xuzhiwen.spring7;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

public class JDBCTest {
    public static void main(String[] args) {
        ApplicationContext app = new ClassPathXmlApplicationContext("common.xml");
        DriverManagerDataSource ds = (DriverManagerDataSource) app.getBean("dataSource");
        System.out.println("url:"+ds.getUrl());
        System.out.println("username:"+ds.getUsername());
        System.out.println("password:"+ds.getPassword());
    }
}