代码摘录册

JavaScript / 格式化时间

function formatDate(date) {
  const d = new Date(date);
  const y = d.getFullYear();
  const m = String(d.getMonth() + 1).padStart(2, "0");
  const day = String(d.getDate()).padStart(2, "0");
  return `${y}-${m}-${day}`;
}

Python / 读取文本文件

from pathlib import Path

file_path = Path("notes.txt")
content = file_path.read_text(encoding="utf-8")
print(content)

CSS / 卡片悬停效果

.card {
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 14px 24px rgba(0, 0, 0, 0.12);
}

Java / 列表转映射

public static Map<Long, User> toUserMap(List<User> users) {
    return users.stream()
        .collect(Collectors.toMap(
            User::getId,
            item -> item,
            (left, right) -> left,
            LinkedHashMap::new
        ));
}

Java / 简单结果封装

public class Result<T> {
    private final boolean success;
    private final String message;
    private final T data;

    private Result(boolean success, String message, T data) {
        this.success = success;
        this.message = message;
        this.data = data;
    }

    public static <T> Result<T> ok(T data) {
        return new Result<>(true, "success", data);
    }
}

HTML / 基础信息卡片

<section class="profile-card">
  <h3>学习主题</h3>
  <p>记录近期整理过的代码片段与注意事项。</p>
  <a href="#snippets">查看摘录</a>
</section>

Java / Stream 分组统计

public Map<String, Long> countSuccessByType(List<OrderLog> logs) {
    return logs.stream()
        .filter(Objects::nonNull)
        .filter(log -> log.getType() != null)
        .collect(Collectors.groupingBy(
            OrderLog::getType,
            LinkedHashMap::new,
            Collectors.filtering(
                log -> Boolean.TRUE.equals(log.getSuccess()),
                Collectors.counting()
            )
        ));
}

Java / 异步批量查询

public CompletableFuture<Map<Long, UserProfile>> loadProfilesAsync(
        List<Long> userIds, Executor executor) {
    List<CompletableFuture<UserProfile>> tasks = userIds.stream()
        .distinct()
        .map(id -> CompletableFuture.supplyAsync(() -> profileService.load(id), executor))
        .toList();

    return CompletableFuture.allOf(tasks.toArray(CompletableFuture[]::new))
        .thenApply(ignored -> tasks.stream()
            .map(CompletableFuture::join)
            .filter(Objects::nonNull)
            .collect(Collectors.toMap(
                UserProfile::getUserId,
                profile -> profile,
                (left, right) -> right
            )));
}

JavaScript / 请求重试封装

async function requestWithRetry(requestFn, retries = 3, delay = 500) {
  let lastError;

  for (let index = 0; index < retries; index += 1) {
    try {
      return await requestFn();
    } catch (error) {
      lastError = error;
      if (index === retries - 1) {
        break;
      }

      await new Promise(resolve => setTimeout(resolve, delay * (index + 1)));
    }
  }

  throw lastError;
}

Python / 递归扫描并汇总

from collections import Counter
from pathlib import Path

def count_suffixes(root: Path) -> Counter:
    counter = Counter()

    for path in root.rglob("*"):
        if path.is_file():
            suffix = path.suffix.lower() or "[no_ext]"
            counter[suffix] += 1

    return Counter(dict(sorted(counter.items(), key=lambda item: item[1], reverse=True)))

SQL / 按月统计活跃用户

SELECT
  DATE_FORMAT(login_time, '%Y-%m') AS login_month,
  COUNT(DISTINCT user_id) AS active_users,
  COUNT(*) AS total_logins
FROM user_login_log
WHERE login_time >= '2026-01-01 00:00:00'
  AND status = 'SUCCESS'
GROUP BY DATE_FORMAT(login_time, '%Y-%m')
ORDER BY login_month DESC;

代码摘录册

常用代码段展示