Cookbooks
Java
Chapter 10. Data Formats and Serialization
Working with TOML

Java:
Working with TOML

How to:

You’ll need a TOML parsing library. I recommend toml4j. Add it to your project like this:

// Add this to your build.gradle
dependencies {
    implementation 'com.moandjiezana.toml:toml4j:0.7.2'
}

Here’s how you parse a TOML file:

import com.moandjiezana.toml.Toml;

public class TomlExample {
    public static void main(String[] args) {
        Toml toml = new Toml().read("""
            [server]
            ip = "192.168.1.1"
            port = 80
            """);

        String ip = toml.getString("server.ip");
        Integer port = toml.getLong("server.port").intValue();
        
        System.out.println("Server IP: " + ip);
        System.out.println("Server Port: " + port);
    }
}

Sample output:

Server IP: 192.168.1.1
Server Port: 80

Deep Dive

Developed by GitHub co-founder Tom Preston-Werner, TOML aimed at being simpler than XML and more specified than YAML. Its latest version 1.0.0, released in 2021, offers a stable set of features.

Alternatives like JSON or YAML are also popular. JSON is great for data interchange. YAML is more human-readable for complex configs. TOML’s strength is its straightforwardness and its use in the Rust community.

As for implementation, when using TOML with Java, keep in mind that the parser you pick matters. Beyond toml4j, some go for jackson-dataformat-toml. They’ll each have nuances, like error handling or parsing performance, so choose based on your project’s needs.

See Also

Working with JSONWorking with XML