How do I stop jackson’s YAML writer from quoting values

I’m working on a project to convert files from JSON to YAML. I’m using the 2.8.3 versions of the following libraries:

• jackson-core
• jackson-databind
• jackson-dataformat-yaml
• jackson-annotations

My YAML serialization code is extremely simple:

ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
ObjectWriter writer = mapper.writer();

try {
    SequenceWriter sw = writer.writeValues(System.out);
    sw.write(tree);
}
catch (IOException e) {
    e.printStackTrace();
}

The YAML produced by this code looks like the following:

serviceType: "elasticSearch"
displayName: "Elasticsearch Service"
description: "Sample Elastic Search Service"

Although it is valid YAML, I don’t like the double quotes around the values. You don’t need them in YAML and it makes editing the resulting file more cumbersome. Does anyone know how to configure the ObjectWriter to make jackson stop encapsulating String values in quotes?

Answer

There is a YAMLGenerator feature called MINIMIZE_QUOTES that will turn off the quotes.

You can enable() it when creating your YAMLFactory like so:

ObjectMapper mapper = new ObjectMapper(new YAMLFactory().enable(YAMLGenerator.Feature.MINIMIZE_QUOTES));