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java8方法中l(wèi)ist集合去重數(shù)據(jù)，一般通過stream的distinct方法。但是distinct不夠靈活，那么該如何解決呢？ 1、自定義去重函數(shù) public static <K,T>Predicate<K> distinctPredicate(Function<K,T>function){
ConcurrentHashMap<T,Boolean> map=new ConcurrentHashMap<>();
return t->null == map.putIfAbsent(function.apply(t),true);
}2、應(yīng)用示例 創(chuàng)建實體類 @AllArgsConstructor
@Data
class Student{
private String name;
private Boolean sex;
private Integer age;
private Double height;
private LocalDate birthday;
}創(chuàng)建測試數(shù)據(jù)，以名字唯一去掉重復(fù)數(shù)據(jù)。 List<Student> studentList = new ArrayList<>();
// 添加測試數(shù)據(jù)，請不要糾結(jié)數(shù)據(jù)的嚴(yán)謹(jǐn)性
studentList.add(new Student("張三", true, 18, 1.75, LocalDate.of(2005, 3, 26)));
studentList.add(new Student("李四", false, 16, 1.67, LocalDate.of(2007, 8, 30)));
studentList.add(new Student("王五", true, 23, 1.89, LocalDate.of(2000, 1, 16)));
studentList.add(new Student("麻六", false, 27, 1.75, LocalDate.of(1996, 9, 20)));
studentList.add(new Student("張三", false, 30, 1.93, LocalDate.of(1993, 6, 19)));
studentList = studentList.stream().filter(distinctPredicate(Student::getName)).collect(Collectors.toList());
log.info(studentList.toString());打印記錄 [Student(name=張三, sex=true, age=18, height=1.75, birthday=2005-03-26), Student(name=李四, sex=false, age=16, height=1.67, birthday=2007-08-30), Student(name=王五, sex=true, age=23, height=1.89, birthday=2000-01-16), Student(name=麻六, sex=false, age=27, height=1.75, birthday=1996-09-20)] |
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