If you're looking to export your data to a JSON object, check out one of the exporters available: https://github.com/mrdoob/three.js/tree/master/utils/exporters
Once you have your JSON object ready:
var loader = new THREE.JSONLoader();
loader.load('obj/model.js', function(geometry, materials) {
// Utilize your geometry and materials as needed
);
For loading OBJ models, you can refer to this example:
Make sure to include the appropriate script for OBJ loading:
var manager = new THREE.LoadingManager();
manager.onProgress = function(item, loaded, total) {
console.log(item, loaded, total);
};
var loader = new THREE.OBJLoader(manager);
loader.load('obj/model.obj', function(object) {
scene.add(object);
});