How to get properties in JSP files using spring mvc 3

Question

I am very new to spring mvc 3 annotation based application. I have two properties files - WEB-INF\resources\general.properties, WEB-INF\resources\jdbc_config.properties

Now I want to configure them through spring-servlet.xml. How I can achieve this?

In general.properties,

label.username = User Name:
label.password = Password:
label.address = Address:

...etc jdbc_config.properties,

app.jdbc.driverClassName=com.mysql.jdbc.Driver
app.jdbc.url=jdbc:mysql://localhost:[port_number]/
app.jdbc.username=root
app.jdbc.password=pass

---etc

If I want to get label.username and app.jdbc.driverClassName in my jsp page, how do I code for them?

I also want to access these properties values from my service. How to get these property values using respective keys in method level in service class or controller class?

Answer 1

You need to distinguish between application properties (configuration) and localisation messages. Both use JAVA properties files, but they serve different purpose and are handled differently.

Note: I am using Java based Spring configuration in the examples bellow. The configuration can be easily made in XML as well. Just check Spring's JavaDoc and reference documentation.

---

Application Properties

Application properties should be loaded as property sources within your application context. This can be done via @PropertySource annotation on your @Configuration class:

@Configuration
@PropertySource("classpath:default-config.properties")
public class MyConfig  {

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }

}

Then you can inject properties using @Value annotation:

@Value("${my.config.property}")
private String myProperty;

---

Localisation Messages

Localisation messages is a little bit different story. Messages are loaded as resource bundles and a special resolution process is in place for getting correct translation message for a specified locale.

In Spring, these messages are handled by MessageSources. You can define your own for example via ReloadableResourceBundleMessageSource:

@Bean
public MessageSource messageSource() {
    ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
    messageSource.setBasename("/WEB-INF/messages/messages");
    return messageSource;
}

You can access these messages from beans if you let Spring inject MessageSource:

@Autowired
private MessageSource messageSource;

public void myMethod() {
    messageSource.getMessage("my.translation.code", null, LocaleContextHolder.getLocale());
}

And you can translate messages in your JSPs by using <spring:message> tag:

<spring:message code="my.translation.code" />