Spring import配置文件使用占位符

import使用占位符

连接池切换导入配置的代码：

1. <import resource="classpath:META-INF/spring/spring-${db.connection.pool}.xml" />

在配置文件添加配置

1. db.connection.pool=druid

启动直接报错，读取不到配置，因为属性文件的加载在import配置文件之后。

1. Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'db.connection.pool' in value "classpath:META-INF/spring/spring-${db.connection.pool}.xml"

所以，要在应用启动的时候添加属性

1、添加AppContextInitializer启动类：

1. public class AppContextInitializer

2.        implements ApplicationContextInitializer<ConfigurableApplicationContext> {

3.    private Logger logger = Logger.getLogger(AppContextInitializer.class);

4.    @Override

5.    public void initialize(ConfigurableApplicationContext applicationContext) {

6.        ResourcePropertySource propertySource = null;

7.        try {

8.            propertySource = new ResourcePropertySource("classpath:config/db-config.properties");

9.        } catch (IOException e) {

10.            logger.error("加载配置文件[config/db-config.properties]失败");

11.        }

12.        applicationContext.getEnvironment().getPropertySources().addFirst(propertySource);

13.    }

14. }

2、在web.xml中添加配置：

1. context-param>  

2.    <param-name>contextInitializerClasses</param-name>  

3.    <param-value>com.example.AppContextInitializer</param-value>  

4. </context-param>

启动配置文件加载正常。