{"id":120,"date":"2026-06-14T09:59:31","date_gmt":"2026-06-14T01:59:31","guid":{"rendered":"https:\/\/www.52runoob.com\/?p=120"},"modified":"2026-06-14T09:59:31","modified_gmt":"2026-06-14T01:59:31","slug":"fastapi-pydantic-%e6%a8%a1%e5%9e%8b","status":"publish","type":"post","link":"https:\/\/www.52runoob.com\/index.php\/2026\/06\/14\/fastapi-pydantic-%e6%a8%a1%e5%9e%8b\/","title":{"rendered":"FastAPI Pydantic \u6a21\u578b"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u5728 FastAPI \u4e2d\uff0c<strong>Pydantic \u6a21\u578b<\/strong>\u662f\u6570\u636e\u9a8c\u8bc1\u3001\u5e8f\u5217\u5316\u548c\u6587\u6863\u751f\u6210\u7684\u7edd\u5bf9\u6838\u5fc3\u3002FastAPI \u6b63\u662f\u901a\u8fc7\u8bfb\u53d6 Pydantic \u6a21\u578b\u4e2d\u7684 Python \u7c7b\u578b\u63d0\u793a\uff0c\u6765\u5b9e\u73b0\u81ea\u52a8\u7684\u6570\u636e\u6821\u9a8c\u548c Swagger \u6587\u6863\u751f\u6210\u7684\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u76ee\u524d FastAPI \u9ed8\u8ba4\u4e14\u5f3a\u70c8\u63a8\u8350\u4f7f\u7528 <strong>Pydantic V2<\/strong>\uff08\u57fa\u4e8e Rust \u7684 <code>pydantic-core<\/code>\uff0c\u901f\u5ea6\u6781\u5feb\uff09\u3002\u4e0b\u9762\u6211\u5c06\u4ece<strong>\u57fa\u7840\u5b9a\u4e49<\/strong>\u3001<strong>\u5b57\u6bb5\u63a7\u5236<\/strong>\u3001<strong>\u8fdb\u9636\u9a8c\u8bc1<\/strong>\u5230<strong>\u6700\u4f73\u5b9e\u8df5<\/strong>\uff0c\u4e3a\u4f60\u7cfb\u7edf\u68b3\u7406 FastAPI \u4e2d\u7684 Pydantic \u6a21\u578b\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u3001 \u57fa\u7840\u8bed\u6cd5\uff1a\u5b9a\u4e49\u4f60\u7684\u7b2c\u4e00\u4e2a\u6a21\u578b<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u53ea\u9700\u7ee7\u627f <code>BaseModel<\/code>\uff0c\u5e76\u4f7f\u7528 Python \u7684<strong>\u7c7b\u578b\u63d0\u793a (Type Hints)<\/strong> \u5373\u53ef\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from pydantic import BaseModel\n\nclass Item(BaseModel):\n    name: str\n    price: float\n    is_offer: bool | None = None  # \u53ef\u9009\u5b57\u6bb5\uff0c\u9ed8\u8ba4\u503c\u4e3a None<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u5728 FastAPI \u4e2d\u4f7f\u7528<\/strong>\uff1a<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from fastapi import FastAPI\n\napp = FastAPI()\n\n@app.post(&quot;\/items\/&quot;)\ndef create_item(item: Item):\n    # FastAPI \u4f1a\u81ea\u52a8\u5c06\u8bf7\u6c42\u7684 JSON \u89e3\u6790\u5e76\u9a8c\u8bc1\u4e3a Item \u5bf9\u8c61\n    # \u5982\u679c price \u662f\u5b57\u7b26\u4e32 &quot;abc&quot;\uff0c\u4f1a\u81ea\u52a8\u8fd4\u56de 422 \u9519\u8bef\n    return {&quot;item_name&quot;: item.name, &quot;item_price&quot;: item.price}<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u3001 \u5f3a\u5927\u7684\u5b57\u6bb5\u63a7\u5236\uff1a<code>Field<\/code> \ud83c\udf1f<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><code>Field<\/code> \u662f Pydantic \u7684\u5229\u5668\uff0c\u7528\u4e8e\u4e3a\u5b57\u6bb5\u6dfb\u52a0<strong>\u6821\u9a8c\u89c4\u5219<\/strong>\u3001<strong>\u9ed8\u8ba4\u503c<\/strong>\u3001<strong>\u6587\u6863\u63cf\u8ff0<\/strong>\u548c<strong>\u793a\u4f8b<\/strong>\uff08\u8fd9\u4e9b\u90fd\u4f1a\u81ea\u52a8\u540c\u6b65\u5230 Swagger UI \u4e2d\uff09\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from pydantic import BaseModel, Field\nfrom typing import Annotated  # Python 3.9+ \u63a8\u8350\u7528\u6cd5\n\nclass UserCreate(BaseModel):\n    # \u57fa\u7840\u6821\u9a8c\uff1a\u957f\u5ea6\u9650\u5236\n    username: str = Field(..., min_length=3, max_length=50, description=&quot;\u7528\u6237\u767b\u5f55\u540d&quot;)\n\n    # \u683c\u5f0f\u6821\u9a8c\uff1a\u5185\u7f6e\u7684 EmailStr \u9700\u8981\u5b89\u88c5 pydantic[email]\n    email: str = Field(..., pattern=r&#039;^[\\w\\.-]+@[\\w\\.-]+\\.\\w+$&#039;, description=&quot;\u7535\u5b50\u90ae\u7bb1&quot;)\n\n    # \u6570\u503c\u6821\u9a8c\uff1age (&gt;=), le (&lt;=), gt (&gt;), lt (&lt;)\n    age: int = Field(default=18, ge=18, le=120, description=&quot;\u7528\u6237\u5e74\u9f84&quot;)\n\n    # \u73b0\u4ee3\u5199\u6cd5\uff1a\u4f7f\u7528 Annotated (\u66f4\u6e05\u6670\uff0c\u63a8\u8350)\n    status: Annotated[str, Field(description=&quot;\u8d26\u6237\u72b6\u6001&quot;, examples=[&quot;active&quot;, &quot;inactive&quot;])] = &quot;active&quot;<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\ud83d\udca1 \u63d0\u793a\uff1a<code>...<\/code> (Ellipsis) \u8868\u793a\u8be5\u5b57\u6bb5\u662f<strong>\u5fc5\u586b\u9879<\/strong> (Required)\u3002<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e09\u3001 Pydantic \u5728 FastAPI \u4e2d\u7684\u201c\u53cc\u91cd\u89d2\u8272\u201d<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u540c\u4e00\u4e2a\u6a21\u578b\uff0c\u65e2\u53ef\u4ee5\u7528\u4f5c<strong>\u8bf7\u6c42\u4f53\u9a8c\u8bc1<\/strong>\uff0c\u4e5f\u53ef\u4ee5\u7528\u4f5c<strong>\u54cd\u5e94\u6a21\u578b\u8fc7\u6ee4<\/strong>\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u4f5c\u4e3a Request Body (\u8f93\u5165\u9a8c\u8bc1)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u786e\u4fdd\u5ba2\u6237\u7aef\u4f20\u6765\u7684\u6570\u636e\u7b26\u5408\u89c4\u8303\uff0c\u4e0d\u7b26\u5408\u5219\u76f4\u63a5\u62e6\u622a\uff0c\u4fdd\u62a4\u4e1a\u52a1\u903b\u8f91\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u4f5c\u4e3a Response Model (\u8f93\u51fa\u8fc7\u6ee4\u4e0e\u5e8f\u5217\u5316)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u662f Pydantic \u6700\u4f18\u96c5\u7684\u7279\u6027\u3002\u5b83\u53ef\u4ee5<strong>\u81ea\u52a8\u8fc7\u6ee4\u6389\u6a21\u578b\u4e2d\u672a\u5b9a\u4e49\u7684\u5b57\u6bb5<\/strong>\uff08\u4f8b\u5982\u5bc6\u7801\u3001\u5185\u90e8 ID\uff09\uff0c\u5e76\u786e\u4fdd\u8fd4\u56de\u7684\u6570\u636e\u7c7b\u578b\u6b63\u786e\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><span>16<\/span><span>17<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">class UserIn(BaseModel):\n    username: str\n    password: str  # \u654f\u611f\u4fe1\u606f\n\nclass UserOut(BaseModel):\n    username: str\n    # \u6ce8\u610f\uff1a\u8fd9\u91cc\u6ca1\u6709 password \u5b57\u6bb5\n\n@app.post(&quot;\/users\/&quot;, response_model=UserOut)\ndef register_user(user: UserIn):\n    # \u6a21\u62df\u4fdd\u5b58\u5230\u6570\u636e\u5e93\n    db_user = {&quot;username&quot;: user.username, &quot;password&quot;: &quot;hashed_&quot; + user.password, &quot;internal_id&quot;: 999}\n\n    # \u5373\u4f7f\u8fd4\u56de\u4e86\u5305\u542b password \u548c internal_id \u7684\u5b57\u5178\n    # response_model=UserOut \u4e5f\u4f1a\u81ea\u52a8\u5c06\u5176\u8fc7\u6ee4\uff0c\u53ea\u8fd4\u56de username\n    return db_user \n    # \u5ba2\u6237\u7aef\u5b9e\u9645\u6536\u5230: {&quot;username&quot;: &quot;alice&quot;}<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u3001 \u8fdb\u9636\u6280\u5de7 (Pydantic V2 \u4e13\u5c5e)<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u5d4c\u5957\u6a21\u578b (Nested Models)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8f7b\u677e\u5904\u7406\u590d\u6742\u7684 JSON \u7ed3\u6784\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">class Address(BaseModel):\n    city: str\n    zipcode: str\n\nclass User(BaseModel):\n    name: str\n    address: Address  # \u5d4c\u5957\u53e6\u4e00\u4e2a\u6a21\u578b\n\n# \u63a5\u6536\u7684 JSON: {&quot;name&quot;: &quot;Alice&quot;, &quot;address&quot;: {&quot;city&quot;: &quot;Beijing&quot;, &quot;zipcode&quot;: &quot;100000&quot;}}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u6a21\u578b\u7ee7\u627f (Model Inheritance)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u590d\u7528\u5b57\u6bb5\u5b9a\u4e49\uff0c\u907f\u514d\u91cd\u590d\u4ee3\u7801\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">class BaseUser(BaseModel):\n    username: str\n    email: str\n\nclass UserCreate(BaseUser):\n    password: str  # \u7ee7\u627f username, email\uff0c\u5e76\u65b0\u589e password\n\nclass UserUpdate(BaseUser):\n    password: str | None = None  # \u7ee7\u627f username, email\uff0cpassword \u53d8\u4e3a\u53ef\u9009<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u81ea\u5b9a\u4e49\u9a8c\u8bc1\u5668 (<code>@model_validator<\/code>)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u5355\u4e2a\u5b57\u6bb5\u7684\u89c4\u5219\u4e0d\u591f\uff0c\u9700\u8981<strong>\u8de8\u5b57\u6bb5\u6821\u9a8c<\/strong>\u6216<strong>\u590d\u6742\u903b\u8f91<\/strong>\u65f6\u4f7f\u7528\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from pydantic import BaseModel, model_validator\n\nclass Event(BaseModel):\n    start_time: int\n    end_time: int\n\n    @model_validator(mode=&#039;after&#039;)\n    def check_times(self) -&gt; &#039;Event&#039;:\n        if self.end_time &lt;= self.start_time:\n            raise ValueError(&quot;\u7ed3\u675f\u65f6\u95f4\u5fc5\u987b\u665a\u4e8e\u5f00\u59cb\u65f6\u95f4&quot;)\n        return self<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. \u8ba1\u7b97\u5b57\u6bb5 (<code>@computed_field<\/code>) (Pydantic V2 \u65b0\u589e)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u6709\u4e9b\u5b57\u6bb5\u4e0d\u9700\u8981\u5ba2\u6237\u7aef\u4f20\u5165\uff0c\u800c\u662f\u6839\u636e\u5176\u4ed6\u5b57\u6bb5\u8ba1\u7b97\u5f97\u51fa\uff0c\u4e14\u9700\u8981\u5305\u542b\u5728\u54cd\u5e94\u4e2d\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from pydantic import BaseModel, computed_field\n\nclass Rectangle(BaseModel):\n    width: float\n    height: float\n\n    @computed_field\n    @property\n    def area(self) -&gt; float:\n        return self.width * self.height\n\nrect = Rectangle(width=10, height=5)\nprint(rect.model_dump()) \n# \u8f93\u51fa: {&#039;width&#039;: 10.0, &#039;height&#039;: 5.0, &#039;area&#039;: 50.0} (area \u4f1a\u81ea\u52a8\u5305\u542b\u5728\u5e8f\u5217\u5316\u7ed3\u679c\u4e2d)<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e94\u3001 \u26a0\ufe0f \u5e38\u89c1\u9677\u9631\u4e0e\u6700\u4f73\u5b9e\u8df5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. Pydantic V1 vs V2 \u8bed\u6cd5\u5dee\u5f02 (\u6781\u6613\u8e29\u5751)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u4f60\u770b\u7684\u662f\u65e7\u6559\u7a0b\uff0c\u8bf7\u6ce8\u610f\u4ee5\u4e0b V2 \u7684\u53d8\u5316\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u274c \u65e7\uff1a<code>item.dict()<\/code> \ud83d\udc49 \u2705 \u65b0\uff1a<code>item.model_dump()<\/code><\/li>\n\n\n\n<li>\u274c \u65e7\uff1a<code>item.json()<\/code> \ud83d\udc49 \u2705 \u65b0\uff1a<code>item.model_dump_json()<\/code><\/li>\n\n\n\n<li>\u274c \u65e7\uff1a<code>@validator<\/code> \/ <code>@root_validator<\/code> \ud83d\udc49 \u2705 \u65b0\uff1a<code>@field_validator<\/code> \/ <code>@model_validator<\/code><\/li>\n\n\n\n<li>\u274c \u65e7\uff1a<code>Field(default_factory=list)<\/code> \ud83d\udc49 \u2705 \u65b0\uff1a\u4f9d\u7136\u652f\u6301\uff0c\u4f46\u4e5f\u53ef\u4ee5\u76f4\u63a5\u7528 <code>list<\/code> \u7c7b\u578b\u63d0\u793a\u914d\u5408\u9ed8\u8ba4\u503c\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u53ef\u53d8\u9ed8\u8ba4\u503c\u9677\u9631<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u867d\u7136 Pydantic V2 \u5bf9\u53ef\u53d8\u9ed8\u8ba4\u503c\u5904\u7406\u5f97\u6bd4\u539f\u751f Python \u597d\uff0c\u4f46\u6700\u4f73\u5b9e\u8df5\u4ecd\u7136\u662f\u4f7f\u7528 <code>default_factory<\/code> \u6765\u751f\u6210\u65b0\u7684\u5217\u8868\u6216\u5b57\u5178\uff0c\u907f\u514d\u591a\u4e2a\u5b9e\u4f8b\u5171\u4eab\u540c\u4e00\u4e2a\u53ef\u53d8\u5bf9\u8c61\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from pydantic import BaseModel, Field\n\nclass Team(BaseModel):\n    # \u2705 \u63a8\u8350\uff1a\u6bcf\u6b21\u5b9e\u4f8b\u5316\u90fd\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u7a7a\u5217\u8868\n    members: list[str] = Field(default_factory=list)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u533a\u5206 <code>Optional<\/code> \u548c \u8d4b\u4e88\u9ed8\u8ba4\u503c<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>age: int | None<\/code>\uff1a\u8868\u793a\u8be5\u5b57\u6bb5<strong>\u53ef\u4ee5<\/strong>\u662f <code>None<\/code>\uff0c\u4f46\u5ba2\u6237\u7aef<strong>\u5fc5\u987b<\/strong>\u663e\u5f0f\u4f20\u9012 <code>\"age\": null<\/code>\u3002<\/li>\n\n\n\n<li><code>age: int | None = None<\/code>\uff1a\u8868\u793a\u8be5\u5b57\u6bb5\u662f<strong>\u53ef\u9009\u7684<\/strong>\uff0c\u5ba2\u6237\u7aef\u53ef\u4ee5\u4e0d\u4f20\uff0cFastAPI \u4f1a\u81ea\u52a8\u5c06\u5176\u8bbe\u4e3a <code>None<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">4. \u4fdd\u6301 Request \u548c Response \u6a21\u578b\u5206\u79bb<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5c3d\u91cf\u4e0d\u8981\u7528\u4e00\u4e2a\u6a21\u578b\u65e2\u505a\u8f93\u5165\u53c8\u505a\u8f93\u51fa\u3002\u8f93\u5165\u6a21\u578b\uff08\u5982 <code>UserCreate<\/code>\uff09\u53ef\u80fd\u5305\u542b\u5bc6\u7801\uff0c\u800c\u8f93\u51fa\u6a21\u578b\uff08\u5982 <code>UserOut<\/code>\uff09\u5e94\u5305\u542b\u6570\u636e\u5e93\u751f\u6210\u7684 <code>id<\/code> \u548c <code>created_at<\/code>\u3002\u5206\u79bb\u5b83\u4eec\u80fd\u8ba9\u4ee3\u7801\u610f\u56fe\u66f4\u6e05\u6670\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u603b\u7ed3\uff1aPydantic \u6a21\u578b\u901f\u67e5\u8868<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">\u9700\u6c42<\/th><th class=\"has-text-align-left\" data-align=\"left\">Pydantic \u89e3\u51b3\u65b9\u6848<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">\u5b9a\u4e49\u6570\u636e\u7ed3\u6784<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u7ee7\u627f <code>BaseModel<\/code> + \u7c7b\u578b\u63d0\u793a<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u5fc5\u586b\u9879<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>field_name: str = Field(...)<\/code><\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u53ef\u9009\u4e14\u5e26\u9ed8\u8ba4\u503c<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>field_name: str | None = None<\/code><\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u6570\u503c\/\u5b57\u7b26\u4e32\u8303\u56f4\u9650\u5236<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>Field(ge=0, le=100, min_length=3)<\/code><\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u8de8\u5b57\u6bb5\u590d\u6742\u6821\u9a8c<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>@model_validator(mode='after')<\/code><\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u52a8\u6001\u8ba1\u7b97\u5e76\u8fd4\u56de\u7684\u5b57\u6bb5<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>@computed_field<\/code> + <code>@property<\/code><\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u5c06\u6a21\u578b\u8f6c\u4e3a\u5b57\u5178 (\u7528\u4e8e\u5b58\u6570\u636e\u5e93)<\/td><td class=\"has-text-align-left\" data-align=\"left\"><code>model.model_dump()<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">\u638c\u63e1\u4e86 Pydantic\uff0c\u4f60\u5c31\u638c\u63e1\u4e86 FastAPI \u6570\u636e\u6d41\u7684\u201c\u5b88\u95e8\u5458\u201d\u3002\u4f60\u53ef\u4ee5\u5c1d\u8bd5\u7528 Pydantic \u5b9a\u4e49\u4e00\u4e2a\u4f60\u5f53\u524d\u9879\u76ee\u4e2d\u7684\u590d\u6742\u4e1a\u52a1\u5bf9\u8c61\uff08\u6bd4\u5982\u5305\u542b\u5d4c\u5957\u5217\u8868\u548c\u81ea\u5b9a\u4e49\u6821\u9a8c\u7684\u8ba2\u5355\u6a21\u578b\uff09\uff0c\u5982\u679c\u9047\u5230\u95ee\u9898\uff0c\u968f\u65f6\u53d1\u7ed9\u6211\u5e2e\u4f60 Review\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 FastAPI \u4e2d\uff0cPydantic \u6a21\u578b\u662f\u6570\u636e\u9a8c\u8bc1\u3001\u5e8f&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14],"tags":[],"class_list":["post-120","post","type-post","status-publish","format-standard","hentry","category-fastapi-"],"_links":{"self":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/comments?post=120"}],"version-history":[{"count":1,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/120\/revisions"}],"predecessor-version":[{"id":121,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/120\/revisions\/121"}],"wp:attachment":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/media?parent=120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/categories?post=120"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/tags?post=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}