REST Assured Tutorial 31 – How To Create POJO Classes Of A Nested JSON Payload

As a part of End to End REST Assured Tutorial , in this post We will learn to create a POJO classes for a nested JSON payload.

We already know now :-

Now we will make it complex by nesting JSON Object and JSON arrays which we see in real time while working.

{
  "companyName": "MSE",
  "companyHOCity": "Benagluru",
  "companyCEO": "Amod",
  "supportedSalaryBanks": [
    "HDFC",
    "ICICI",
    "AXIS"
  ],
  "pincodesOfCityOffice": [
    560037,
    360034,
    456343
  ],
  "employee": [
    {
      "firstName": "Amod",
      "lastName": "Mahajan",
      "gender": "Male",
      "age": 28,
      "salary": 10000.56,
      "married": false
    },
    {
      "firstName": "Animesh",
      "lastName": "Prashant",
      "gender": "Male",
      "age": 30,
      "salary": 20000.56,
      "married": false
    },
    {
      "firstName": "Kitty",
      "lastName": "Gupta",
      "gender": "Female",
      "age": 26,
      "salary": 30000.56,
      "married": false
    }
  ],
  "contractors": [
    {
      "firstName": "Seema",
      "lastName": "Singh",
      "contractFrom": "Jan-2019",
      "contractTo": "JAN-2025"
    },
    {
      "firstName": "Hari",
      "lastName": "Prasad",
      "contractFrom": "Jan-2017",
      "contractTo": "JAN-2030"
    }
  ],
  "companyPFDeails": {
    "pfName": "XYZ",
    "pfCity": "Benagluru",
    "pfYear": 2012,
    "noOfEmployees": 10
  }
}

Creating POJO classes are simple if we identify what are classes we need to create correctly. A final POJO class for a JSON Payload is created by combining multiple blocks. Let’s identify different objects or POJO :-

There is no need to create a POJO for a 1:1 fields. We can include them in a final POJO class. For example :- In above payload field names like “companyName” , “companyHOCity” and “companyCEO” are 1:1 mapped. Observe value of field name “supportedSalaryBanks“. It is kind of an array of strings which does not need a user defined class to represent specially. Similarly field name “pincodesOfCityOffice” has value as an array of integers. We can define above discussed field as below :-

private String companyName;
private String companyHOCity;
private String companyCEO;
private List supportedSalaryBanks;
private List pincodesOfCityOffice;

Now focus on field “employee” which has value as an array of employees. We do not have any ready made data type to represent element of this array as a whole. So here we need to create a POJO class which can contain all details of an employee. Create a simple POJO class to represent below data:-

{
      "firstName": "Amod",
      "lastName": "Mahajan",
      "gender": "Male",
      "age": 28,
      "salary": 10000.56,
      "married": false
}

To represent an array of employees :-

List employee;

Similar concept for field name “contractors”.

List contractors;

Field name “companyPFDeails” contains value as JSON object which is not present in Java. So we need to create a class for it like Employee above.

CompanyPFDeails companyPFDeails;

Once all building blocks are ready you need to create a final POJO class where all blocks will be kept together to represent whole payload.

package RestfulBookerPojo;

public class Employee {

        // private variables or data members of pojo class
        private String firstName;
        private String lastName;
        private String gender;
        private int age;
        private double salary;
        private boolean married;
        
        // Getter and setter methods
        public String getFirstName() {
                return firstName;
        }
        public void setFirstName(String firstName) {
                this.firstName = firstName;
        }
        public String getLastName() {
                return lastName;
        }
        public void setLastName(String lastName) {
                this.lastName = lastName;
        }
        public String getGender() {
                return gender;
        }
        public void setGender(String gender) {
                this.gender = gender;
        }
        public int getAge() {
                return age;
        }
        public void setAge(int age) {
                this.age = age;
        }
        public double getSalary() {
                return salary;
        }
        public void setSalary(double salary) {
                this.salary = salary;
        }
        public boolean getMarried() {
                return married;
        }
        public void setMarried(boolean married) {
                this.married = married;
        }       
}
package RestfulBookerPojo;

public class Contractors {
        private String firstName;
        private String lastName;
        private String contractFrom;
        private String contractTo;
        
        public String getFirstName() {
                return firstName;
        }
        public void setFirstName(String firstName) {
                this.firstName = firstName;
        }
        public String getLastName() {
                return lastName;
        }
        public void setLastName(String lastName) {
                this.lastName = lastName;
        }
        public String getContractFrom() {
                return contractFrom;
        }
        public void setContractFrom(String contractFrom) {
                this.contractFrom = contractFrom;
        }
        public String getContractTo() {
                return contractTo;
        }
        public void setContractTo(String contractTo) {
                this.contractTo = contractTo;
        }

}
package RestfulBookerPojo;

public class CompanyPFDeails {
        private String pfName;
        private String pfCity;
        private int pfYear;
        private int noOfEmployees;
        
        public String getPfName() {
                return pfName;
        }
        public void setPfName(String pfName) {
                this.pfName = pfName;
        }
        public String getPfCity() {
                return pfCity;
        }
        public void setPfCity(String pfCity) {
                this.pfCity = pfCity;
        }
        public int getPfYear() {
                return pfYear;
        }
        public void setPfYear(int pfYear) {
                this.pfYear = pfYear;
        }
        public int getNoOfEmployees() {
                return noOfEmployees;
        }
        public void setNoOfEmployees(int noOfEmployees) {
                this.noOfEmployees = noOfEmployees;
        }
}
package RestfulBookerPojo; import java.util.List; public class NestedPOJO { private String companyName; private String companyHOCity; private String companyCEO; private List supportedSalaryBanks; private List pincodesOfCityOffice; List employee; List contractors; CompanyPFDeails companyPFDeails; public String getCompanyName() { return companyName; } public void setCompanyName(String companyName) { this.companyName = companyName; } public String getCompanyHOCity() { return companyHOCity; } public void setCompanyHOCity(String companyHOCity) { this.companyHOCity = companyHOCity; } public String getCompanyCEO() { return companyCEO; } public void setCompanyCEO(String companyCEO) { this.companyCEO = companyCEO; } public List getSupportedSalaryBanks() { return supportedSalaryBanks; } public void setSupportedSalaryBanks(List supportedSalaryBanks) { this.supportedSalaryBanks = supportedSalaryBanks; } public List getPincodesOfCityOffice() { return pincodesOfCityOffice; } public void setPincodesOfCityOffice(List pincodesOfCityOffice) { this.pincodesOfCityOffice = pincodesOfCityOffice; } public List getEmployee() { return employee; } public void setEmployee(List employee) { this.employee = employee; } public List getContractors() { return contractors; } public void setContractors(List contractors) { this.contractors = contractors; } public CompanyPFDeails getCompanyPFDeails() { return companyPFDeails; } public void setCompanyPFDeails(CompanyPFDeails companyPFDeails) { this.companyPFDeails = companyPFDeails; } }

Let’s create a JSON Payload using above POJO classes.

package RestfulBookerPojo; import java.util.ArrayList;
import java.util.List; import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper; public class CreateNestedJSONFromPOJOClasses { public static void main(String[] args) throws JsonProcessingException { NestedPOJO nestedPOJO = new NestedPOJO(); nestedPOJO.setCompanyName("MSE"); nestedPOJO.setCompanyHOCity("Benagluru"); nestedPOJO.setCompanyCEO("Amod"); List supportedSalaryBanks = new ArrayList(); supportedSalaryBanks.add("HDFC"); supportedSalaryBanks.add("ICICI"); supportedSalaryBanks.add("AXIS"); nestedPOJO.setSupportedSalaryBanks(supportedSalaryBanks); List pincodesOfCityOffice = new ArrayList(); pincodesOfCityOffice.add(560037); pincodesOfCityOffice.add(360034); pincodesOfCityOffice.add(456343); nestedPOJO.setPincodesOfCityOffice(pincodesOfCityOffice); // Create first employee Employee amod = new Employee(); amod.setFirstName("Amod"); amod.setLastName("Mahajan"); amod.setAge(28); amod.setGender("Male"); amod.setSalary(10000.56); amod.setMarried(false); // Create second employee Employee animesh = new Employee(); animesh.setFirstName("Animesh"); animesh.setLastName("Prashant"); animesh.setAge(30); animesh.setGender("Male"); animesh.setSalary(20000.56); animesh.setMarried(true); // Create third employee Employee kitty = new Employee(); kitty.setFirstName("Kitty"); kitty.setLastName("Gupta"); kitty.setAge(26); kitty.setGender("Female"); kitty.setSalary(30000.56); kitty.setMarried(false); // Creating a List of Employees List allEMployees = new ArrayList(); allEMployees.add(amod); allEMployees.add(animesh); allEMployees.add(kitty); nestedPOJO.setEmployee(allEMployees); Contractors seema = new Contractors(); seema.setFirstName("Seema"); seema.setLastName("Singh"); seema.setContractFrom("Jan-2019"); seema.setContractTo("JAN-2025"); Contractors hari = new Contractors(); hari.setFirstName("Hari"); hari.setLastName("Prasad"); hari.setContractFrom("Jan-2017"); hari.setContractTo("JAN-2030"); List allContractors = new ArrayList(); allContractors.add(seema); allContractors.add(hari); nestedPOJO.setContractors(allContractors); CompanyPFDeails companyPFDeails = new CompanyPFDeails(); companyPFDeails.setPfName("XYZ"); companyPFDeails.setPfCity("Benagluru"); companyPFDeails.setPfYear(2012); companyPFDeails.setNoOfEmployees(10); nestedPOJO.setCompanyPFDeails(companyPFDeails); ObjectMapper objectMapper = new ObjectMapper(); String nestedJsonPayload = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(nestedPOJO); System.out.println(nestedJsonPayload); }
}
{
  "companyName" : "MSE",
  "companyHOCity" : "Benagluru",
  "companyCEO" : "Amod",
  "supportedSalaryBanks" : [ "HDFC", "ICICI", "AXIS" ],
  "pincodesOfCityOffice" : [ 560037, 360034, 456343 ],
  "employee" : [ {
    "firstName" : "Amod",
    "lastName" : "Mahajan",
    "gender" : "Male",
    "age" : 28,
    "salary" : 10000.56,
    "married" : false
  }, {
    "firstName" : "Animesh",
    "lastName" : "Prashant",
    "gender" : "Male",
    "age" : 30,
    "salary" : 20000.56,
    "married" : true
  }, {
    "firstName" : "Kitty",
    "lastName" : "Gupta",
    "gender" : "Female",
    "age" : 26,
    "salary" : 30000.56,
    "married" : false
  } ],
  "contractors" : [ {
    "firstName" : "Seema",
    "lastName" : "Singh",
    "contractFrom" : "Jan-2019",
    "contractTo" : "JAN-2025"
  }, {
    "firstName" : "Hari",
    "lastName" : "Prasad",
    "contractFrom" : "Jan-2017",
    "contractTo" : "JAN-2030"
  } ],
  "companyPFDeails" : {
    "pfName" : "XYZ",
    "pfCity" : "Benagluru",
    "pfYear" : 2012,
    "noOfEmployees" : 10
  }
}

Note – I have used Jackson Java library to convert a Java object to String. Make sure you have latest dependency added. For this example I have used below maven dependency : –

  com.fasterxml.jackson.core jackson-databind 2.11.0

You can download/clone above sample project from here.

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