JsonObject filesJsonObject = jo.getAsJsonObject("files");
Set<Map.Entry<String, JsonElement>> filesJsonObjectEntrySet = filesJsonObject.entrySet();
for (Map.Entry<String, JsonElement> es : filesJsonObjectEntrySet) {
	JsonObject joIn = es.getValue().getAsJsonObject();
　　　　String filename = joIn.getString("filename");
	String language =joIn.getString("language");
	String rawUrl=joIn.getString("raw_url");
	String size=joIn.getString("size");
	String type=joIn.getString("type");
}