Spring中引用外部资源文件

1.xml中配置属性

当我们导入druid和mysql的资源jar包后可以直接配置数据库连接对象

<?xml version="1.0" encoding="UTF-8"?> <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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/bank"/> <property name="username" value="root"/> <property name="password" value="1234"/> </bean> </beans>

然后可以测试一下

public class Test { public static void main(String[] args)throws Exception { ApplicationContext ac = new ClassPathXmlApplicationContext("datasource.xml"); DruidDataSource d1 = ac.getBean("datasource", DruidDataSource.class); System.out.println(d1.getConnection()); } }

输出结果：

2.创建properties属性文件

创建一个properties配置文件:

# k = v jdbc.driver=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/bank jdbc.username=root jdbc.password=1234

然后加载配置文件

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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"> <!-- 加载资源文件--> <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="location" value="db.properties"/> </bean> <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="${jdbc.driver}"/> <property name="url" value="${jdbc.url}"/> <property name="username" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> </bean> </beans>

测试后运行结果 3. 引入context名称空间

<?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"> <!-- 指定properties属性文件的位置 --> <!-- classpath:xxx 表示属性文件位于类路径下 --> <context:property-placeholder location="db.properties"/> <bean id="datasource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="${jdbc.driver}"/> <property name="url" value="${jdbc.url}"/> <property name="username" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> </bean> </beans>

测试一下：