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Note that the output file is simply a text file with the extension .json . Thus it can be read by any program that is capable of reading plain text files.

The end of the program

Listing 6 also signals the end of the main method and the end of the program.

The contents of the output file

Figure 1 shows a "prettified" version of the contents of the output file.

Figure 1. Prettified version of output file contents. {"game": [{ "cards":[ "2-club","3-heart","4-diamond","5-spade"],"name":"Tom" },{ "cards":[ "4-heart","5-heart","6-club","7-diamond"],"name":"Joe" }] }

The actual contents of the file do not contain line breaks and indentation as shown in Figure 1 . Those cosmetic features were added manually to Figure 1 to make it easier for you to correlate the output with the code shown earlier. Instead, the actual file consists simply of a string ofcharacters that begins as shown in Figure 2 .

Figure 2. Beginning of output file contents. {"game":[{"cards":["2-club","3-heart","4-diamond","5-spade"],...

Decoded output data

As mentioned earlier, a later page in this book will read the JSON string from the file and decode it into its component parts. Figure 3 shows a preview of what you will see on that page.

Figure 3. Decoded output data. First Player's Name: Tom First Player's cards2-club 3-heart4-diamond 5-spadeSecond Player's Name: Joe Second Player's cards4-heart 5-heart6-club 7-diamond

Figure 3 shows the JSON string decoded and formatted into a display that is representative of the intent of the string -- to encapsulate information aboutthe players and their cards in a game of cards.

Run the program

I encourage you to copy the code from Listing 7 . Execute the code and confirm that your output file matches that shown in Figure 2 . Experiment with the code, making changes, and observing the results of your changes. Make certain that youcan explain why your changes behave as they do.

Complete program listing

Listing 7 provides a complete listing of the program named Code.java .

Listing 7 . The program named Code.java. /************************************************ Copyright: R.G.Baldwin 2016Revised: 06/01/16 Creates a json string and writes it to an outputfile. The json string contains an array, which in turn contains two arrays.Tested with Java 8, Windows 7, and json-simple-1.1.1.************************************************/ import org.json.simple.JSONObject;import org.json.simple.JSONArray; import java.io.PrintWriter;import java.io.File; import java.io.IOException;class Code{ public static void main(String[]args){ //Create a json object. which is a subclass// of the Java HashMap class. JSONObject hashMapA = new JSONObject();//Populate the json object with a key/value// pair. hashMapA.put("name","Tom");//Create and populate a json array, which is// a subclass of the Java ArrayList class. JSONArray arrayListA = new JSONArray();arrayListA.add("2-club"); arrayListA.add("3-heart");arrayListA.add("4-diamond"); arrayListA.add("5-spade");//Populate the json object with a key/value// pair where the value is an array. hashMapA.put("cards",arrayListA);//Create and populate another similar json// object. JSONObject hashMapB = new JSONObject();hashMapB.put("name","Joe");JSONArray arrayListB = new JSONArray(); arrayListB.add("4-heart");arrayListB.add("5-heart"); arrayListB.add("6-club");arrayListB.add("7-diamond"); hashMapB.put("cards",arrayListB);//Create another json array and populate// it with the two json objects created // earlier.JSONArray arrayListC = new JSONArray(); arrayListC.add(hashMapA);arrayListC.add(hashMapB); //Create another json object and populate// it with a key/value pair where the value // is the array from above.JSONObject hashMapC = new JSONObject(); hashMapC.put("game",arrayListC);try{//Encode the HashMap object into a // json String and write it to an output// file. Note that it is simply a text file // with a different extension.PrintWriter out = new PrintWriter(new File("junk.json"));hashMapC.writeJSONString(out); out.flush();}catch(IOException ex){ ex.printStackTrace();}//end catch }//end main}//end class Code


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Json0225: Encoding JSON Arrays
  • File: Json0225.htm
  • Published: 06/01/16

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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