How can I send Korean with the get String?

in android,

Ion.with(this)
.load(url + user_name)
.asString()
.setCallback(new FutureCallback() { ... });

in node.js,

router.get('url/:user_name', function(req, res, next) {
let user_name = req.params.user_name;
console.log("print : ", user_name);
});

it works, but node can't read Korean characters
"print : ì ±ì¤" <- The letters are broken

How can I send Korean with the GET?