如：角色去重处理
baseRoleList = baseRoleList.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(role -> role.getRoleId()))), ArrayList::new));
原文链接：
https://blog.csdn.net/qq_28988969/article/details/81119587
有一个list,实体包含多个字段,当其中两个字段值均相同时,就认为list中的这两条记录是一样的
java8中有一个collectingAndThen可以根据多个字段去重
依据姓名和年龄去重,当姓名和年龄相同时,认为这两个实体相同
class FlightTicketInfo {
private String orderNumber;
private String userName;
private String age;
public FlightTicketInfo(String orderNumber, String userName, String age) {
this.orderNumber = orderNumber;
this.userName = userName;
this.age = age;
}
@Override
public String toString() {
return "FlightTicketInfo{" +
"orderNumber=‘" + orderNumber + ‘\‘‘ +
", userName=‘" + userName + ‘\‘‘ +
", age=‘" + age + ‘\‘‘ +
‘}‘;
}
public String getOrderNumber() {
return orderNumber;
}
public String getUserName() {
return userName;
}
public String getAge() {
return age;
}
}
@Test
public void testList(){
List<FlightTicketInfo> infoList = new ArrayList<>();
infoList.add(new FlightTicketInfo("11111", "xiaoming", "22"));
infoList.add(new FlightTicketInfo("22222", "xiaoming", "22"));
infoList.add(new FlightTicketInfo("33333", "xiaoming", "23"));
infoList.add(new FlightTicketInfo("11111", "xiaoming", "22"));
infoList.stream()
.collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(f -> f.getUserName()+f.getAge()))), ArrayList::new))
.forEach(System.out::println);
}
原文：https://www.cnblogs.com/vae860514/p/10832414.html