Spring load properties file and MessageFormat

During yesterday's code review, learn another way to load properties file by using Spring. Spring is so powerful, I love it!

I found there are two ways to do that:

1. use <util:properties>

1) Define your properties file test.properties

username=test

2) you need to define that in you applicationContext.xml to load the properties file.

<util:properties id="myProps" location="classpath:*.properties />

3) In you controller or other spring bean classes, you can use

@Controller
public class MyController{

	@Value("#myprops[username]")
	private String username;

}

I didn't test it. Just searched online. 

2. use context:property-placeholder

1) test.properties

username=test

2) Define context:property-placeholder in your context.xml.

<context:property-placeholder location="classpath*:youbar*.properties"
		ignore-resource-not-found="false" local-override="false"
		ignore-unresolvable="false" />

Here I ran into a problem that I can't place the code above into applicationContext.xml, I have another youbarportlet.xml. The applicationContext.xml is loaded from web.xml from context-param, the second is like spring-servlet.xml.

I haven't entirely sure about the problem.

3) Access property through @Value annotation

@Controller
public class MyController{

	@Value("${username}")
	private String username;

}

Then you can use the value anywhere in your controller. It's really convenient, right?

In case, you want to customize the value of properties.

greeting=Welcome, firstname lastname

firstname and lastname can't be defined in the properties. In this case, you need to use placeholder and then you MessageFormat to replace them.

greeting=Welcome, {0} {1}!

@Controllerpublic class MyController{
    @Value("${greeting}")
    private String greeting;

    public void renderView(){
        String newGreeting = MessageFormat.format(greeting, "test", "test");
    }
}

Then you'll see the value of newGreeting = Welcome, test test!