java中按字段对自定义对象类进行多重排序 package com.learnjava； 导入java.io.IOException； 导入java.nio.file.Files； 导入java.nio.file.path； 导入java.util.array； 导入java.util.Collections； 导入java.util.Comparator； 导入java.util.List； 导入java.util.Scanner； 导入java.util.stream.stream； 公共类EmployeeSortByGroup{ 公共静态无效排序EmployeeByGRP（列出人员，字符串[]排序）{ 对于（int i=0；i

使用

您现在可以轻松地增强解析以支持降序排序，例如，通过在字段名后添加一个

-

减号，这样

“firstname-；age”

将按

firstname

降序排序，然后按

age

升序排序

// You will now use it like this. No need for using a List
Arrays.sort(persons, parsePersonSortBy(sortByString));

publicstaticcomparatorparsesortby（stringsortby，functionfieldcomparatormapper）{
比较器sortComparator=null；
for（字符串字段：sortBy.split（“；”））{
布尔降序=字段.endsWith（“-”）；
比较器c=fieldComparatorMapper.apply（降序？field.substring（0，field.length（）-1）：字段）；
如果（降序）
c=c.反向（）；
sortComparator=（sortComparator==null？c:sortComparator.ThenComparating（c））；
}
返回排序比较程序；
}

生成一个

Map@SanjayKumarNayak不要在评论中添加额外信息。编辑问题（问题下方的灰色链接）以澄清问题。
public static Comparator<Person> parseSortBy(String sortBy) {
    Comparator<Person> sortComparator = null;
    for (String field : sortBy.split(";")) {
        Comparator<Person> c;
        switch (field) {
            case "firstname":
                c = Comparator.comparing(Person::getFirstName);
                break;
            case "lastname":
                c = Comparator.comparing(Person::getLastName);
                break;
            case "age":
                c = Comparator.comparingInt(Person::getAge);
                break;
            case "country":
                c = Comparator.comparing(Person::getCountry);
                break;
            default:
                throw new IllegalArgumentException("Unknown sort spec: " + field);
        }
        sortComparator = (sortComparator == null ? c : sortComparator.thenComparing(c));
    }
    return sortComparator;
}

public static Comparator<Person> parsePersonSortBy(String sortBy) {
    return parseSortBy(sortBy, field -> {
        switch (field) {
            case "firstname": return Comparator.comparing(Person::getFirstName);
            case "lastname":  return Comparator.comparing(Person::getLastName);
            case "age":       return Comparator.comparingInt(Person::getAge);
            case "country":   return Comparator.comparing(Person::getCountry);
            default: throw new IllegalArgumentException("Unknown sort spec: " + field);
        }
    });
}

// The following method should be in a separate helper class for reusability
public static <E> Comparator<E> parseSortBy(String sortBy, Function<String, Comparator<E>> fieldComparatorMapper) {
    Comparator<E> sortComparator = null;
    for (String field : sortBy.split(";")) {
        Comparator<E> c = fieldComparatorMapper.apply(field);
        sortComparator = (sortComparator == null ? c : sortComparator.thenComparing(c));
    }
    return sortComparator;
}

// You will now use it like this. No need for using a List
Arrays.sort(persons, parsePersonSortBy(sortByString));

public static <E> Comparator<E> parseSortBy(String sortBy, Function<String, Comparator<E>> fieldComparatorMapper) {
    Comparator<E> sortComparator = null;
    for (String field : sortBy.split(";")) {
        boolean descending = field.endsWith("-");
        Comparator<E> c = fieldComparatorMapper.apply(descending ? field.substring(0, field.length() - 1) : field);
        if (descending)
            c = c.reversed();
        sortComparator = (sortComparator == null ? c : sortComparator.thenComparing(c));
    }
    return sortComparator;
}