Spring Boot : Using PropertySource annotation to read custom .properties file

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As we know, we can use Value annotation to read application.properties file.

application.properties -

name = John
title = Mayer
server.port = 8080

TestController.java -

package com.example.customconfiguration.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/root")
public class TestController {
    @Value("${name}")
    String name;

    @Value("${title}")
    String title;

    @GetMapping("/controller")
    public String controllerTest() {
        return "Hello " + name + title;
    }
}

Similarly we can create a custom properties file and read the values in the file using PropertySource Annotation.

custom.properties -

customName = Japanese
customTitle = Mornings

CustomController.java -

package com.example.customconfiguration.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.PropertySource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/custom")
@PropertySource("classpath:custom.properties")
public class CustomController {

    @Value("${customName}")
    String name;

    @Value("${customTitle}")
    String title;


    @GetMapping("/controller")
    public String controllerTest() {
        return "Hello " + name + title;
    }
}

In the above code, we are using a PropertySource annotation and passing the filename to be read. If there are multiple files to be read, we can use multiple PropertySource annotaiton or we can use PropertySources :

@PropertySources({     
   @PropertySource("classpath:test1.properties"),
   @PropertySource("classpath:test2.properties") 
}) 
public class Properties{
     //code
}

Conclusion :

This article explained how to read a custom properties file using PropertySource.