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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

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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.
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