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How to read/parse JSON array using Java?
A Json array is an ordered collection of values that are enclosed in square brackets i.e. it begins with ‘[’ and ends with ‘]’. The values in the arrays are separated by ‘,’ (comma).
Sample JSON array
{
"books": [ Java, JavaFX, Hbase, Cassandra, WebGL, JOGL]
}The json-simple is a light weight library which is used to process JSON objects. Using this you can read or, write the contents of a JSON document using Java program.
JSON-Simple maven dependency
Following is the maven dependency for the JSON-simple library −
<dependencies> <dependency> <groupId>com.googlecode.json-simple</groupId> <artifactId>json-simple</artifactId> <version>1.1.1</version> </dependency> </dependencies>
Paste this with in the <dependencies> </dependencies> tag at the end of your pom.xml file. (before </project> tag)
Example
First of all, let us create a JSON document with name sample.json with the 6 key-value pairs and an array as shown below −
{
"ID": "1",
"First_Name": "Krishna Kasyap",
"Last_Name": "Bhagavatula",
"Date_Of_Birth": "1989-09-26",
"Place_Of_Birth":"Vishakhapatnam",
"Salary": "25000"
"contact": [
"e-mail: krishna_kasyap@gmail.com",
"phone: 9848022338",
"city: Hyderabad",
"Area: Madapur",
"State: Telangana"
]
}To read an array from a JSON file using a Java program −
- Instantiate the JSONParser class of the json-simple library.
JSONParser jsonParser = new JSONParser();
- Parse the contents of the obtained object using the parse() method.
//Parsing the contents of the JSON file
JSONObject jsonObject = (JSONObject) jsonParser.parse(new FileReader("E:/players_data.json"));- Retrieve the value associated with a key using the get() method.
String value = (String) jsonObject.get("key_name");- Just like other element retrieve the json array using the get() method into the JSONArray object.
JSONArray jsonArray = (JSONArray) jsonObject.get("contact");- The iterator() method of the JSONArray class returns an Iterator object using which you can iterate the contents of the current array.
//Iterating the contents of the array
Iterator<String> iterator = jsonArray.iterator();
while(iterator.hasNext()) {
System.out.println(iterator.next());
}Following Java program parses the above created sample.json file, reads its contents and, displays them.
Example
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class ReadingArrayFromJSON {
public static void main(String args[]) {
//Creating a JSONParser object
JSONParser jsonParser = new JSONParser();
try {
//Parsing the contents of the JSON file
JSONObject jsonObject = (JSONObject) jsonParser.parse(new FileReader("E:/test.json"));
//Forming URL
System.out.println("Contents of the JSON are: ");
System.out.println("ID: "+jsonObject.get("ID"));
System.out.println("First name: "+jsonObject.get("First_Name"));
System.out.println("Last name: "+jsonObject.get("Last_Name"));
System.out.println("Date of birth: "+ jsonObject.get("Date_Of_Birth"));
System.out.println("Place of birth: "+ jsonObject.get("Place_Of_Birth"));
System.out.println("Salary: "+jsonObject.get("Salary"));
//Retrieving the array
JSONArray jsonArray = (JSONArray) jsonObject.get("contact");
System.out.println("");
System.out.println("Contact details: ");
//Iterating the contents of the array
Iterator<String> iterator = jsonArray.iterator();
while(iterator.hasNext()) {
System.out.println(iterator.next());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
}Output
Contents of the JSON are: ID: 1 First name: Krishna Kasyap Last name: Bhagavatula Date of birth: 1989-09-26 Place of birth: Vishakhapatnam Salary: 25000 Contact details: e-mail: krishna_kasyap@gmail.com phone: 9848022338 city: Hyderabad Area: Madapur State: Telangana
Updated on: 31-Oct-2023
50K+ Views
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