Next.js 15 Fullstack (App Router + Server Actions) · 课时

服务端数据获取

在服务器组件中使用 `fetch` 和其他方法实现可靠的服务端数据获取，以获得最佳性能

服务端数据获取 是 CoddyKit 上的免费 Next.js 15 Fullstack (App Router + Server Actions) 课时。这是第 1 节课，共 3 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Next.js 15 Fullstack (App Router + Server Actions) 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Next.js 15 Fullstack (App Router + Server Actions) 课程共包含 3 节课。

本课时的部分内容尚未翻译，以英文显示。

Why Fetch Data on the Server?

Next.js 15 excels at rendering your application on the server. This is super powerful for performance and SEO!

When you fetch data directly on the server, your users see content faster because the HTML is already built with data. It also helps search engines index your content better.

Performance: Faster initial page loads.
SEO: Content is available for crawlers.
Security: Keep sensitive logic on the server.

Enhanced `fetch` for Server Components

In Next.js 15 Server Components, the standard fetch Web API is automatically enhanced. This means it comes with built-in caching and revalidation features.

You can use fetch directly inside your async Server Components to get data from external APIs or your own backend services.

Fetching Data in a Component

Let's see how simple it is to fetch data. Here, we'll get a single "Todo" item from a public API. Notice the async keyword on the component function.

Next.js handles the waiting for data before rendering the component.

Run This Basic Fetch Example

This JavaScript code demonstrates fetching data from a public API. While a Next.js Server Component uses JSX, the underlying fetch logic is the same. Run it to see the data!

async function fetchTodo() {
  const url = 'https://jsonplaceholder.typicode.com/todos/1';
  try {
    const response = await fetch(url);
    if (!response.ok) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    const data = await response.json();
    console.log("Fetched Todo Title:", data.title);
  } catch (error) {
    console.error("Fetch failed:", error);
  }
}

fetchTodo();

Automatic Caching with `fetch`

By default, Next.js automatically caches the results of fetch requests in Server Components. If the same fetch request is made again (e.g., across multiple components or re-renders), Next.js will use the cached data.

This is fantastic for performance as it avoids redundant network requests.

Opting Out of Caching

Sometimes, you need the freshest data, bypassing the cache. You can do this by passing an option to fetch: { cache: 'no-store' }. This tells Next.js to always refetch the data.

Use 'no-store' for highly dynamic data that changes frequently and needs to be up-to-date on every request.

async function fetchFreshData() {
  const url = 'https://jsonplaceholder.typicode.com/posts/1';
  // 'no-store' ensures data is always fresh
  const response = await fetch(url, { cache: 'no-store' });
  const data = await response.json();
  console.log("Fresh Post Title:", data.title);
}

fetchFreshData();

Revalidating Data on Demand

What if you want cached data, but also want to specify how often it should be considered "fresh"? You can use the next.revalidate option with fetch.

This sets a time-to-live (TTL) for the data. After this time, the next request will refetch the data and update the cache.

async function fetchRevalidatedData() {
  const url = 'https://jsonplaceholder.typicode.com/users/1';
  // Revalidate data every 60 seconds
  const response = await fetch(url, { next: { revalidate: 60 } });
  const data = await response.json();
  console.log("User Name (revalidated):", data.name);
}

fetchRevalidatedData();

`revalidate` vs. `no-store`

Choosing between cache: 'no-store' and next: { revalidate: N } depends on your data's needs:

no-store: Use for data that must be absolutely fresh on every request (e.g., real-time stock prices, user-specific shopping cart).
revalidate: N: Use for data that can be slightly stale but should update periodically (e.g., blog posts, product listings that change hourly).
Default (cached): Use for static or infrequently changing data (e.g., navigation links, static page content).

Beyond `fetch`: Direct Database Access

While fetch is powerful for external APIs, Server Components can also directly interact with databases or ORMs like Prisma. Since Server Components run on the server, they can safely contain database credentials.

This means you can write code like await prisma.user.findMany() directly in your components, keeping your client bundle small and secure.

Data Fetching Options

Which of the following statements about server-side data fetching in Next.js 15 are TRUE?

Recap: Server-Side Fetching

You've learned how to harness server-side data fetching in Next.js 15!

fetch in Server Components is automatically optimized with caching.
Use cache: 'no-store' for always-fresh data.
Use next: { revalidate: N } for time-based data freshness.
Server Components can also directly access databases securely.

Mastering these techniques is key to building fast, efficient, and secure Next.js applications.

常见问题解答

「服务端数据获取」课时是免费的吗？

是的 — 「服务端数据获取」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Next.js 15 Fullstack (App Router + Server Actions) 课程的其余内容，请升级到 CoddyKit PRO。 Next.js 15 Fullstack (App Router + Server Actions) 课程共包含 3 节课。

「服务端数据获取」这节课中我会学到什么？

在服务器组件中使用 `fetch` 和其他方法实现可靠的服务端数据获取，以获得最佳性能你通过在浏览器中直接运行的动手代码来练习 Next.js 15 Fullstack (App Router + Server Actions)，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Next.js 15 Fullstack (App Router + Server Actions) 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Next.js 15 Fullstack (App Router + Server Actions) 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 1 节课，共 3 节。

「服务端数据获取」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Next.js 15 Fullstack (App Router + Server Actions) 课中编写并运行代码吗？

能。每节 Next.js 15 Fullstack (App Router + Server Actions) 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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