java比较器按多个字段排序

本文介绍了java比较器按多个字段排序的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

需要按3个String字段对Dir类进行排序.第一个:按1个值排序- s1 ；然后按字符串长度排序- s1 + s2 + s3 ;按2个值排序后- s2 ;然后按3个值- s3 进行排序.在我的代码中，它适用于值1和字符串长度排序，但按2值排序不起作用.我如何按多个值对Dir类进行排序?班长:

Need to sort class Dir by 3 String fields. First one: sort by 1 value -s1; Then sort by String length - s1+s2+s3; After sort by 2 value - s2; And sort by 3 value - s3. In my code its works for value 1 and String length sorting, but sorting by 2 value does not works. How i can sorting class Dir by multiple values? Class Dir:

public class Dir { private String s1 = ""; private String s2 = ""; private String s3 = ""; public Dir(String s1){ this.s1 = s1; } public Dir(String s1, String s2){ this.s1 = s1; this.s2 = s2; } public Dir(String s1, String s2, String s3){ this.s1 = s1; this.s2 = s2; this.s3 = s3; } public String getS1() { return s1; } public void setS1(String s1) { this.s1 = s1; } public String getS2() { return s2; } public void setS2(String s2) { this.s2 = s2; } public String getS3() { return s3; } public void setS3(String s3) { this.s3 = s3; } @Override public String toString() { return s1 + "\\" + s2 +"\\"+ s3 ; } } //Comparator for 2 value: public class DirReversComparatorS2 implements Comparator<Dir> { @Override public int compare(Dir o1, Dir o2) { if ((o1.getS2()pareTo(o2.getS2())) > 0) { return -1; } else if ((o1.getS2()pareTo(o2.getS2())) < 0) { return 1; } else { return 0; } } } //Comparator for 3 value public class DirReversComparatorS3 implements Comparator<Dir> { @Override public int compare(Dir o1, Dir o2) { if ((o1.getS3()pareTo(o2.getS3())) > 0) { return -1; } else if ((o1.getS3()pareTo(o2.getS3())) < 0) { return 1; } else { return 0; } }

}

//Comparator for string lenght: public class DirReversStringComparator implements Comparator<Dir> { @Override public int compare(Dir o1, Dir o2) { if (o1.toString().length() > o2.toString().length()) { return 1; } else { return -1; } }

}

//Main class: public class Main { public static void main(String[] args){ Comparator<Dir> dcomp = new DirComparatorS1().thenComparing(new DirComparatorS2( ).thenComparing(new DirComparatorS3())); TreeSet<Dir> dir = new TreeSet<>(dcomp); dir.add(new Dir("K1")); dir.add(new Dir("K1","SK2")); dir.add(new Dir("K1","SK1","SSK2")); dir.add(new Dir("K1", "SK1", "SSK1")); dir.add(new Dir("K2")); dir.add(new Dir("K2", "SK2", "SSK1")); dir.add(new Dir("K2", "SK2", "SSK2")); dir.add(new Dir("K2", "SK3", "SSK2")); dir.add(new Dir("K2", "SK2", "SSK3")); System.out.println("Отсортирован по возрастанию"); for(Dir d : dir){ System.out.println(d.getS1()+"\\"+d.getS2()+"\\"+d.getS3()); } //This code does not works! Comparator<Dir> reverse = new DirReversComparatorS1().thenComparing( new DirReversStringComparator()).thenComparing( new DirReversComparatorS2()).thenComparing( new DirReversComparatorS3()); TreeSet<Dir> rdir = new TreeSet<>(reverse); rdir.add(new Dir("K1")); rdir.add(new Dir("K1","SK2")); rdir.add(new Dir("K2","SK2")); rdir.add(new Dir("K1","SK1","SSK2")); rdir.add(new Dir("K1", "SK1", "SSK1")); rdir.add(new Dir("K1", "SK1", "SSK2")); rdir.add(new Dir("K2")); rdir.add(new Dir("K2", "SK4", "SSK3")); rdir.add(new Dir("K2", "SK2", "SSK5")); rdir.add(new Dir("K2","SK1")); rdir.add(new Dir("K2", "SK2", "SSK1")); rdir.add(new Dir("K1", "SK1")); rdir.add(new Dir("K2", "SK2", "SSK2")); rdir.add(new Dir("K1", "SK2")); rdir.add(new Dir("K2", "SK3", "SSK2")); rdir.add(new Dir("K2", "SK2", "SSK3")); rdir.add(new Dir("K2", "SK2", "SSK5")); rdir.add(new Dir("K2", "SK1", "SSK3")); rdir.add(new Dir("K1", "SK3")); rdir.add(new Dir("K1", "SK3", "SSK1")); System.out.println("Отсортирован по убыванию"); for(Dir d : rdir){ System.out.println(d.getS1()+"\\"+d.getS2()+"\\"+d.getS3()); } } }

解决方案是什么?Tnx！

What is the solution? Tnx!

推荐答案

类似以下内容:

dirs .sort(Comparatorparing(Dir::getS1) .thenComparingInt( d -> d.getS1().length() + d.getS2().length() + d.getS3().length()) .thenComparing(Dir::getS2) .thenComparing(Dir::getS3));