Java escape JSON String?

I would use a library to create your JSON String for you. Some options are:

• GSON
• Crockford's lib

This will make dealing with escaping much easier. An example (using org.json) would be:

JSONObject obj = new JSONObject();

obj.put("id", userID);
obj.put("type", methoden);
obj.put("msg", msget);

// etc.

final String json = obj.toString(); // <-- JSON string

The JSON specification at https://www.json.org/ is very simple by design. Escaping characters in JSON strings is not hard. This code works for me:

private String escape(String raw) {
    String escaped = raw;
    escaped = escaped.replace("\\", "\\\\");
    escaped = escaped.replace("\"", "\\\"");
    escaped = escaped.replace("\b", "\\b");
    escaped = escaped.replace("\f", "\\f");
    escaped = escaped.replace("\n", "\\n");
    escaped = escaped.replace("\r", "\\r");
    escaped = escaped.replace("\t", "\\t");
    // TODO: escape other non-printing characters using uXXXX notation
    return escaped;
}