The elements of a JSON array can be accessed in a similar way: String name = jsonArray.get( 0 ).asString() Int age = jsonObject.get( "age" ).asInt() // asLong(), asDouble(). Once you have a JsonObject, you can access its contents using the get() method: String name = jsonObject.get( "name" ).asString() JsonArray jsonArray = JsonArray.readFrom( string ) You can read a JSON object or array from a Reader or from a String: JsonObject jsonObject = JsonObject.readFrom( reader ) It is fast, lightweight, consists only of 10 classes and I hope it’s simple to use: Usage The result is called minimal-json and it’s already included in RAP.
Simple to use – we’ll expose the API for custom component developers, so it should be simple and clear.Minimal – the less code the better, as we have to maintain it.Lightweight – it should deal with memory sparingly as we deal with lots of messages.Fast – we read and create so much JSON that the parser directly affects the server performance.It went so well that I decided to continue and create a JSON parser tailored to our needs. Why is JSON parsing so easy? That’s because the first character of every token uniquely defines its type ( '[' for an array, '"' for a string, 't' or 'f' for a boolean, and so forth). One winter Sunday, I started to write a JSON parser just for the fun of it, and was quickly surprised how simple it is to parse JSON. As we like to keep the core library self-contained, we don’t want a dependency to an external JSON library. We really only need a bare-bones parser that can read JSON into a simple Java representation and generate JSON from Java. There are many better JSON libraries out there, but most do much more than we need. When we switched to JSON, we included the org.json parser, which is reasonably small but not famous for its performance. For this reason, we need something fast for this job. In the RAP project, reading and writing JSON are critical operations, since the server processes and creates JSON messages for a large number of clients at a high rate.
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