spring | 引用外部属性文件

引用外部属性文件

1.项目目录

2.导入druid-1.1.9.jar、mysql-connector-java-5.1.7-bin.jar

3.db.properties

# k = v
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=123456

4.datasource.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: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-4.0.xsd">
    
    <!-- 直接配置 -->
    <!-- <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/test"></property>
        <property name="username" value="root"></property>
        <property name="password" value="123456"></property>
    </bean> -->
    
    <!-- 加载资源文件（引用外部资源文件） -->
    <!-- <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="db.properties"></property>
    </bean>
    <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driver}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean> -->
    
    <!-- 使用context标签加载资源文件（引用外部属性文件） -->
    <context:property-placeholder location="db.properties"/>
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="db.properties"></property>
    </bean>
    <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driver}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean> 
</beans>

5.Test.java

package com.atguigu.ioc.datasource;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.alibaba.druid.pool.DruidDataSource;

public class Test {

    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        ApplicationContext ac = new ClassPathXmlApplicationContext("datasource.xml");
        
        DruidDataSource bean = ac.getBean("datasource", DruidDataSource.class);
        
        System.out.println(bean);
        
        //System.out.println(bean.getConnection());
    }

}