CODEWITHSUNDEEP
java
Unknown Guy
Unknown Guy

Reputation: 137

How do copy properties from one object to another in java

I have two classes, Employee and Customer, which have similar properties like name, id, et cetera. I want to populate objects from List<Employee> empList to List<Customer> customerList and vice versa.

List<Employee> empList = getEmployeeList();
// Here is what I am trying so far
List<Customer> customers = new ArrayList<>();
empList.foreach(e -> {
    Customer customer = new Customer();
    customer.setCustomerName(e.getEmployeeName()); // Et cetera
    customers.add(cutomer);
});
// What I am looking for
List<Customer> customers = Utils.getObject(empList, Customer.class);

Here are my POJOs

class Employee {
    private String employeeName;
    private int age;
    private EmployeeDetails details;
}

class EmployeeDetails {
    private String name;
    private int salary;
}

class Customer {
    private String customerName;
    private int age;
    private CustomerDetails details;
}

class CustomerDetails {
    private String name;
    private int salary;
}

Instead of manually populating list from employee to customer and vice versa I want to use any third-party library like Apache Commons.

Upvotes: 6

Views: 31742

Answers (3)

ovod
ovod

Reputation: 123

may be Mapstruct lib can help you to map objects

Upvotes: 1

VGR
VGR

Reputation: 44414

Reflection is usually the worst way to accomplish something:

  • Reflection cannot be checked at compile-time for errors.
  • Reflection is rarely optimized by the Java runtime.
  • Relying on identical property names is invisible to maintainers of either class.

Instead, you can create an additional constructor:

public Customer(Employee source) {
    setCustomerName(source.getEmployeeName());
    setAge(source.getAge());

    if (source.getDetails() != null) {
        setDetails(new CustomerDetails(source.getDetails()));
    }
}

And:

public CustomerDetails(EmployeeDetails source) {
    setName(source.getName());
    setSalary(source.getSalary());
}

That way, everything is checked for correctness when you compile. Also, you can be smart about copying mutable child objects.

Before you object to how much work it is to write the get- and set-calls by hand, consider that you only have to write the code once. It won’t really take that much time, will it?

Upvotes: 2

Alien
Alien

Reputation: 15908

You can use BeanUtils:

import org.apache.commons.beanutils.BeanUtils;

Employee newObject = new Employee(); 
BeanUtils.copyProperties(newObject, oldObject);

If looking for deep copy then Use SerializationUtils.clone method from the Apache Commons Lang. It copies the entire class hierarchy.

SerializationUtils.clone(object);

Upvotes: 11

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