spring PropertyPlaceholderConfigurer and context:property-placeholder

Question

I have following bean declaration:

  <bean      class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">         <property name="locations">             <list>                 <value>WEB-INF/classes/config/properties/database.properties</value>                 <value>classpath:config/properties/database.properties</value>             </list>         </property>         <property name="ignoreResourceNotFound" value="true"/>     </bean> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">     <property name="driverClassName" value="${jdbc.driverClassName}" />     <property name="url" value="${jdbc.url}" />     <property name="username" value="${jdbc.username}" />     <property name="password" value="${jdbc.password}" /> </bean> 

Now I want to change above PropertyPlaceholderConfigurer to following format:

<context:component-scan base-package="org.example.config"/> <util:properties id="jdbcProperties"             location="classpath:config/properties/database.properties"/> 

1. ignoreResourceNotFound will ignore the property while running. e.g: When testing application WEB-INF/.. path will ignore( since maven project and property file is under src/main/resources/..), while launching web application, other property will ignore path, I need to implement same with above format.
2. should be able to add multiple property file like database.properties, test.properties etc.
3. in Spring 3, can I use annotation instead of these xml files for DB loading, how can I do it? since I am using only one xml file(given above) to load db stuff.

I am using Spring 3 framework.

Answer 1

<context:property-placeholder ... /> is the XML equivalent to the PropertyPlaceholderConfigurer. So, prefer that. The <util:properties/> simply factories a java.util.Properties instance that you can inject.

In Spring 3.1 (not 3.0...) you can do something like this:

@Configuration @PropertySource("/foo/bar/services.properties") public class ServiceConfiguration {       @Autowired Environment environment;       @Bean public javax.sql.DataSource dataSource( ){          String user = this.environment.getProperty("ds.user");         ...     }  } 

In Spring 3.0, you can "access" properties defined using the PropertyPlaceHolderConfigurer mechanism using the SpEl annotations:

@Value("${ds.user}") private String user; 

If you want to remove the XML all together, simply register the PropertyPlaceholderConfigurer manually using Java configuration. I prefer the 3.1 approach. But, if youre using the Spring 3.0 approach (since 3.1's not GA yet...), you can now define the above XML like this:

@Configuration  public class MySpring3Configuration {              @Bean          public static PropertyPlaceholderConfigurer configurer() {               PropertyPlaceholderConfigurer ppc = ...              ppc.setLocations(...);              return ppc;          }           @Bean          public class DataSource dataSource(                 @Value("${ds.user}") String user,                  @Value("${ds.pw}") String pw,                  ...) {              DataSource ds = ...             ds.setUser(user);             ds.setPassword(pw);                                     ...             return ds;         } } 

Note that the PPC is defined using a static bean definition method. This is required to make sure the bean is registered early, because the PPC is a BeanFactoryPostProcessor - it can influence the registration of the beans themselves in the context, so it necessarily has to be registered before everything else.