list,去重

import java.util.*;
import java.util.stream.Collectors;

public class ExcelUtil {

private static String[] params = {"p001","p002","p003","p004"};

public static void main(String[] args) {

List<Datum> dataList = new ArrayList<>();

for (int i = 0; i < 100; i++) {
if (i%2==0){
Datum datum = new Datum(
params[new Random().nextInt(params.length)],
params[new Random().nextInt(params.length)],
params[new Random().nextInt(params.length)],
params[new Random().nextInt(params.length)],
params[new Random().nextInt(params.length)]
);
dataList.add(datum);
}
}

System.out.println("0 size : "+dataList.size()+" -> "+dataList);

// 单条件
ArrayList<Datum> collect1 = dataList.stream().collect(Collectors.collectingAndThen(
Collectors.toCollection(() -> new TreeSet<Datum>(
Comparator.comparing(
Datum::getId))), ArrayList::new));

System.out.println("1 size : "+collect1.size()+" -> "+collect1);

// 两个条件
ArrayList<Datum> collect2 = dataList.stream().collect(Collectors.collectingAndThen(
Collectors.toCollection(() -> new TreeSet<>(
Comparator.comparing(p->p.getId() + ";" + p.getAddress()))), ArrayList::new));

System.out.println("2 size : "+collect2.size()+" -> "+collect2);

// 三个条件
ArrayList<Datum> collect3 = dataList.stream().collect(Collectors.collectingAndThen(
Collectors.toCollection(() -> new TreeSet<>(
Comparator.comparing(p->p.getInfo() + ";" + p.getAddress()+";"+p.getName()))), ArrayList::new));

System.out.println("3 size : "+collect3.size()+" -> "+collect3);

}

}