Question

我正在尝试按整数排序数组List<Entry<String, Integer>>。在开始时，我的代码将文本文件读取为字符串。然后是字符串拆分为单词并保存到字符串数组，所有单词都更改为小写。然后使用哈希映射保存单词和他们的计数。然后将哈希映射转换为数组列表。现在我需要使用比较器按整数对此列表进行排序。我尝试了很多方法，但没有结果。这是我的代码，对不起我的英文：

package test2;

import java.io.*;
import java.util.*;
import java.util.Map.Entry;

public class Test2 {

    public static void main(String[] args) throws Exception {

        try {
            File file = new File("filee.txt");
            BufferedReader reader = new BufferedReader(new FileReader(file));
            StringBuilder build = new StringBuilder(150000);
            String line;
            while ((line = reader.readLine()) != null) {
                build.append(line);
            }
            reader.close();

            String text = "";
            text = build.toString();
            String[] words;
            words = text.split("[,; .\\-\\\"]");

            String text0 = "";
            for (String str0 : words) {
                text0 = text0 + str0 + " ";
            }

            for (int i = 0; i < words.length; i++) {
                words[i] = words[i].toLowerCase();
            }

            Map<String, Integer> count = new HashMap<String, Integer>();
            for (int i = 0; i < words.length; i++) {
                if (count.containsKey(words[i])) {
                    count.put(words[i], count.get(words[i]) + 1);
                } else {
                    count.put(words[i], 1);
                }
            }

            for (Map.Entry<String, Integer> entry : count.entrySet()) {
                System.out.println(entry.getKey() + " : " + entry.getValue());
            }

            List<Entry<String, Integer>> list = new ArrayList<Entry<String, Integer>>(count.entrySet());
            //Here I need to sort list using Collections.sort(list, Comparator)            


            for (int i = 0; i < list.size(); i++) {
                System.out.println(list.get(i).getKey() + " : " + list.get(i).getValue());
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }

    }

}

Answer 1

试试这个：

Collections.sort(count.entrySet(), new Comparator<Entry<String, Integer>>() {
    @Override
    public int compare(Entry<String, Integer> x, Entry<String, Integer> y) {
        return x.getValue() - y.getValue();
    }
});

Answer 2

尝试：

@Override
    public int compare(Entry<String, Integer> arg0, Entry<String, Integer> arg1) {
        if (arg0 == null && arg1 != null){
            return -1;
        }else if (arg0 != null && arg1 == null){
            return 1;
        }else if (arg0 == null && arg1 == null){
            return 0;
        }

        if (arg0.getValue() == null && arg1.getValue() != null){
            return -1;
        }else if (arg0.getValue() != null && arg1.getValue() == null){
            return 1;
        }else if (arg0.getValue() == null && arg1.getValue() == null){
            return 0;
        }

        return arg0.getValue().compareTo(arg1.getValue());
    }

排序列表<entry <string，integer =“”>＆gt;使用比较器</entry <string，>

2 个答案: