Property placeholder from Configuration

Question

With Spring in xml context we can simple load properties like this:

<context:property-placeholder location:"classpath*:app.properties"/>

Is there any chance to configure same properties inside @Configuration bean (~ from java code) without boilerplate?

Thanks!

Answer 1

You can use the annotation @PropertySource like this

@Configuration
@PropertySource(value="classpath*:app.properties")
public class AppConfig {
 @Autowired
 Environment env;

 @Bean
 public TestBean testBean() {
     TestBean testBean = new TestBean();
     testBean.setName(env.getProperty("testbean.name"));
     return testBean;
 }
}

See: http://static.springsource.org/spring/docs/3.1.x/javadoc-api/org/springframework/context/annotation/PropertySource.html

EDIT: if you are using spring boot you can use @ConfigurationProperties annotation to wire the properties file directly to bean properties, like this:

test.properties

name=John Doe
age=12

PersonProperties.java

@Component
@PropertySource("classpath:test.properties")
@ConfigurationProperties
public class GlobalProperties {

    private int age;
    private String name;

    //getters and setters
}

source: https://www.mkyong.com/spring-boot/spring-boot-configurationproperties-example/

Answer 2

Manual configuration can be done via following code

public static PropertySourcesPlaceholderConfigurer loadProperties(){
  PropertySourcesPlaceholderConfigurer propertySPC =
   new PropertySourcesPlaceholderConfigurer();
  Resource[] resources = new ClassPathResource[ ]
   { new ClassPathResource( "yourfilename.properties" ) };
  propertySPC .setLocations( resources );
  propertySPC .setIgnoreUnresolvablePlaceholders( true );
  return propertySPC ;
}

Sources: Property Placeholder

Answer 3

One easy solution is that your bean will also contain some init function:

In your spring configuration, you may mention it:

<bean id="TestBean" class="path to your class" init-method="init" singleton="false" lazy-init="true" >

init will be called after all properties will be set via setters, in this method you may override properties that have been already set, you may also set any properties.