18 | 散列表（上）：Word 文档中的单词拼写检查功能是如何实现的

package com.controller.bootweb.demo.dsa;
import java.io.BufferedReader;import java.io.FileReader;import java.io.IOException;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.stream.Collectors;
public class URLSorter {
    public static void main(String[] args) {        String logFilePath = "/Users/arvin/workspace/logs/access.log";
        try {            Map<String, Integer> urlCounts = countURLVisits(logFilePath);            List<Map.Entry<String, Integer>> sortedURLs = sortURLsByVisits(urlCounts);
            // 输出排序后的结果            for (Map.Entry<String, Integer> entry : sortedURLs) {                System.out.println(entry.getKey() + ": " + entry.getValue() + " visits");            }        } catch (IOException e) {            e.printStackTrace();        }    }
    // 读取日志文件并统计访问次数    private static Map<String, Integer> countURLVisits(String logFilePath) throws IOException {        Map<String, Integer> urlCounts = new HashMap<>();
        try (BufferedReader reader = new BufferedReader(new FileReader(logFilePath))) {            String line;            while ((line = reader.readLine()) != null) {                String url = extractURL(line);                urlCounts.put(url, urlCounts.getOrDefault(url, 0) + 1);            }        }
        return urlCounts;    }
    // 提取URL的辅助函数    private static String extractURL(String logLine) {        // 根据日志格式提取URL        // 示例：假设日志行的格式是 "timestamp URL"        String[] parts = logLine.split("https://", 2);        return parts.length > 1 ? parts[1].trim() : "";    }
    // 排序URL及其访问次数    private static List<Map.Entry<String, Integer>> sortURLsByVisits(Map<String, Integer> urlCounts) {        return urlCounts.entrySet()                .stream()                .sorted(Map.Entry.<String, Integer>comparingByValue().reversed())                .collect(Collectors.toList());    }}

2022-01-01 10:00:00.000 https://time.geekbang.com/column/article/645862022-01-01 10:01:00.000 https://time.geekbang.com/column/article/645862022-01-01 10:02:00.000 https://time.geekbang.com/column/article/645862022-01-01 10:03:00.000 https://time.geekbang.com/column/article/645862022-01-01 10:04:00.000 https://time.geekbang.com/column/article/645222022-01-01 10:05:00.000 https://time.geekbang.com/column/article/645122022-01-01 10:06:00.000 https://time.geekbang.com/column/article/645862022-01-01 10:07:00.000 https://time.geekbang.com/column/article/645122022-01-01 10:09:00.000 https://time.geekbang.com/column/article/64186

package com.controller.bootweb.demo.dsa;
import java.util.Arrays;import java.util.HashSet;import java.util.Set;
public class CommonStringsFinder {
    public static void main(String[] args) {        // 两个字符串数组        String[] array1 = {"apple", "banana", "orange", "kiwi", "grape"};        String[] array2 = {"kiwi", "grape", "watermelon", "apple", "pear"};
        // 找出相同的字符串        String[] commonStrings = findCommonStrings(array1, array2);
        // 输出结果        System.out.println("Common Strings: " + Arrays.toString(commonStrings));    }
    // 找出两个数组中相同的字符串    private static String[] findCommonStrings(String[] array1, String[] array2) {        Set<String> set1 = new HashSet<>(Arrays.asList(array1));        Set<String> set2 = new HashSet<>(Arrays.asList(array2));
        // 使用retainAll方法找出两个集合的交集        set1.retainAll(set2);
        // 将交集转换为数组        String[] commonStrings = set1.toArray(new String[0]);
        return commonStrings;    }}