Java 8 Collectors.joining Example with Delimiters

Leave a Comment

In Java 8 Collectors.joining() method is used to combine elements of a stream into a single string. It is especially useful when you want to join a list of strings using a delimiter, along with optional prefix and suffix values.

Collectors.joining():

Collectors.joining() is a method in the java.util.stream.Collectors class. It is used to concatenate stream elements into a single string.

In this example, we fetch employee company names and join them using a delimiter, prefix, and suffix.

  • First, we create a list of EmployeeCompany objects.
  • Using stream(), we process the list .
  • The map() method extracts company names.
  • Finally, Collectors.joining() joins the names:
    1. : → delimiter
    2. [ → prefix
    3. ] → suffix
				
					// Model class:-

class EmployeeCompany {

	private String companyName;
	private String companyAddress;

	public EmployeeCompany(String companyName, String companyAddress) {
		super();
		this.companyName = companyName;
		this.companyAddress = companyAddress;
	}

	public String getCompanyName() {
		return companyName;
	}

	public void setCompanyName(String companyName) {
		this.companyName = companyName;
	}

	public String getCompanyAddress() {
		return companyAddress;
	}

	public void setCompanyAddress(String companyAddress) {
		this.companyAddress = companyAddress;
	}

}

// Main class:-

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class CompanyListJoin {
	public static void main(String[] args) {
		List<EmployeeCompany> getList = Arrays.asList(
		new EmployeeCompany("TechMahindra", "Mumbai"),
		new EmployeeCompany("TCS", "Pune"), new EmployeeCompany("Wipro", "Bangalore"));
		String str = getList.stream().map(employee
		             -> employee.getCompanyName())
			     	.collect(Collectors.joining(":", "[", "]"));
		System.out.println("Company name Joining:-- " + str);
	}

}

Output :-
Company name Joining:– [TechMahindra:TCS:Wipro]

Related Posts