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{"student":true,"name":"Joe","age":21}
{"student":false,"name":"Sue","age":32}{"student":true,"name":"Tom","age":19} The format for each line of text that you see in Figure 1 is the format that you would expect for a JSON string that doesn't include array data. (See Introducing JSON for more details regarding format.)
Briefly, each key is separated from its value by a colon (:) . Each key/value pair is separated from its neighbors by a comma (,) . The JSON string begins with a left brace ({) and ends with a right brace (}) . Keys are surrounded by double quotation characters. Values may or may not beseparated by double quotation characters, depending on their type. Some characters inside of values, such as double quotation characters and backslashcharacters must be escaped with a backslash character (\" and \\) but that is not shown by this program.
Note that the display order for the key/value pairs shown in Figure 1 does not match the order in which the objects were populated in Listing 2 and Listing 3 . A HashMap does not impose an ordering on its contents and does not guarantee that the ordering will remainconstant over time.
Listing 5 also signals the end of the main method and the end of the program.
I encourage you to copy the code from Listing 6 . Execute the code and confirm that you get the same results as those shown in Figure 1 . 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.
A complete listing of the program named Code.java is provided in Listing 6 .
/********************************************************************
Copyright 2016 R.G.BaldwinConstructs three JSONObject objects and saves them in an ArrayList.
Transforms each JSONObject object into a String object and saves thestrings in a second ArrayList object.
Displays the strings.Tested with Java 8, Win 7, and json-simple-1.1.1.jar.
********************************************************************/import org.json.simple.JSONObject;
import java.util.ArrayList;import java.util.Iterator;
class Code {public static void main(String[] args){//Create a container for several JSON objects.
ArrayList<JSONObject>listA = new ArrayList<JSONObject>();
//Create a container for several JSON stringsArrayList<String>listB = new ArrayList<String>();//Create and populate the first JSONObject with unordered
// key/value pairs.listA.add(new JSONObject());
listA.get(0).put("name","Joe");listA.get(0).put("age",21);
listA.get(0).put("student",true);//Create and populate the second JSONObject. Note that the object// is populated in a different order than above.
listA.add(new JSONObject());listA.get(1).put("student",false);
listA.get(1).put("name","Sue");listA.get(1).put("age",32);//Create and populate the third JSONObject
listA.add(new JSONObject());listA.get(2).put("name","Tom");
listA.get(2).put("age",19);listA.get(2).put("student",true);
//Transform the three JSON objects into JSON strings and save// them in ListB. Could write them to disk for transfer to a
// different programming environment at this point.Iterator<JSONObject>iteratorA = listA.iterator();
while (iteratorA.hasNext()){listB.add(iteratorA.next().toJSONString());
}//end while loop//Display the JSON strings currently stored in listB. Note that
// the display order does not necessarily match the order in// which the original objects were populated.
Iterator<String>iteratorB = listB.iterator();
while (iteratorB.hasNext()){System.out.println(iteratorB.next());
}//end while loop}//end main
}//end class Code This section contains a variety of miscellaneous information.
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.
-end-
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