The list set is de duplicated according to the object attributes

scene ： according to list Some properties in the object （ Non empty ） duplicate removal , Keep unique values

  Ideas ： Make attributes unique keys , Then go heavy.

Example ： Add an object repeatedly and test

import lombok.Data;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.TreeSet;

import static java.util.stream.Collectors.collectingAndThen;
import static java.util.stream.Collectors.toCollection;

/**
 * description:
 */
@Data
public class Org {
    private String id;
    private String pid;

    public static void main(String[] args) {

        List<Org> importList = new ArrayList<>();

        Org org = new Org();
        org.setId("001");
        org.setPid("002");

        Org org1 = new Org();
        org1.setId("002");
        org1.setPid("003");

        Org org2 = new Org();
        org2.setId("003");
        org2.setPid("001");

        importList.add(org);
        importList.add(org);
        importList.add(org1);
        importList.add(org2);
        
        ArrayList<Org> collect = importList.stream().collect(collectingAndThen(toCollection(() -> new TreeSet<>(Comparator.comparing(dto -> dto.getId() + dto.getPid()))), ArrayList::new));
        System.out.println(collect);
        
    }
}