spring載入properties檔案

以JDBC為例

<?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-3.1.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.1.xsd">
        <bean id="databaseTest" class="com.alibaba.druid.pool.DruidDataSource">
                <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/mall?serverTimezone=UTC"></property>
                <property name="username" value="root"></property>
                <property name="password" value="root"></property>
        </bean>
</beans>
 

之前通過bean依賴注入--普通資料型別，注入了jdbc連線引數，現在將這些屬性放到一個獨立的properties檔案中：

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mall?serverTimezone=UTC
jdbc.username=root
jdbc.password=root

xml修改為：

<?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-3.1.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.1.xsd">
        <!--載入外部properties檔案，先引入context名稱空間，第4，7，8行所示-->
        <!--載入外部properties檔案-->
        <context:property-placeholder location="classpath:jdbc.properties"/>

        <bean id="databaseTest" 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>