Get the values from the properties file at runtime based on the input - java Spring

Question

I have my colour.roperties file as

rose = red
lily = white
jasmine = pink

I need to get the value for colour as

String flower = runTimeFlower;
@Value("${flower}) String colour;

where flower value we will get at runtime. How can I do this in java Spring. I need to get a single value (from among 50 values defined in the properties file )at runtime based on the user input. If i cannot use @Value , Could you tell me other ways to handle this please?

Answer 1

There is no way to do what you are describing using @Value, but you can do this, which is the same thing pretty much:

package com.acme.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

@Component
public class Example {
    private @Autowired Environment environment;

    public String getFlowerColor(String runTimeFlower) {
        return environment.resolvePlaceholders("${" + runTimeFlower + "}");
    }
}

Answer 2

The PropertySources which Spring reads from won't know the value of the flower variable, so @Value won't work.

Inject a Properties object or a Map. Then just look up the colour using the property name or key, respectively, e.g.

<util:properties id="appProperties" location="classpath:app.properties" />

...

@Autowired 
@Qualifier("appProperties")
private Properties appProperties;

...

appProperties.getProperty(flower);