如何实现java8 list按照元素的某个字段去重
作者：良人与我
这篇文章主要介绍了如何实现java8 list按照元素的某个字段去重，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，,需要的朋友可以参考下
list 按照元素的某个字段去重
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {
private Integer age;
private String name;
}
测试数据
List<Student> studentList = Lists.newArrayList(); studentList.add(new Student(28, "river")); studentList.add(new Student(12, "lucy")); studentList.add(new Student(33, "frank")); studentList.add(new Student(33, "lucy"));
java8 通过tree set 去重
List<Student> studentDistinctList = studentList.stream() .collect(Collectors.collectingAndThen (Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(t -> t.getName()))), ArrayList::new ) ); System.out.println(new Gson().toJson(studentDistinctList));
扩展distinct 方法去重
List<Student> studentDistinct2List = studentList.stream().filter(StreamUtil.distinctByKey(t->t.getName())) .collect(Collectors.toList()); System.out.println(new Gson().toJson(studentDistinct2List));
工具类
public class StreamUtil {
/**
* https://stackoverflow.com/questions/23699371/java-8-distinct-by-property
* @param keyExtractor
* @param <T>
* @return
*/
public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
Set<Object> seen = ConcurrentHashMap.newKeySet();
return t -> seen.add(keyExtractor.apply(t));
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。