Spring之使用外部属性文件

先导入C3P0数据源

1.新建db.properties

user=root
password=langsin
driverClass=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql:///test

2.新建XML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-3.1.xsd">
    
    <!-- 导入属性文件 -->
    <context:property-placeholder location="classpath:db.properties"/>
    
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 使用外部属性化文件的属性 -->
        <property name="user" value="${user}"></property>
        <property name="password" value="${password}"></property>
        <property name="driverClass" value="${driverClass}"></property>
        <property name="jdbcUrl" value="${jdbcUrl}"></property>
    </bean>
</beans>

3.测试类Main

import javax.sql.DataSource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {
    
    public static void main(String[] args) throws Exception {
        
        ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-properties.xml");
        
        DataSource dataSource = (DataSource) ctx.getBean("dataSource");
        System.out.println(dataSource.getConnection());
        
    }
}

4.输出结果

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
com.mchange.v2.c3p0.impl.NewProxyConnection@6a510e39

只要能打印出上述结果，则说明数据库连接没问题