AI很方便，不过我还是建议学点Mermaid基础

前言

当我们需要使用模型绘制Mermaid图的时候，我们通常可以输入类似如下的提示词，只需要要求模型 "mermaid格式输出" 或者 "输出mermaid" 即可

复制代码

以mermaid格式输出浏览器从输入ULR到解析出页面的完整过程

然后我们将得到一段mermaid代码

rust 复制代码

sequenceDiagram
    participant User
    participant Browser
    participant DNS
    participant Server
    participant RenderEngine
    User->>Browser: 输入URL并回车
    Browser->>Browser: 1. 解析URL
    alt 缓存检查
        Browser->>Browser: 检查强缓存(Expires/Cache-Control)
        Browser-->>User: 命中缓存? 直接返回资源
    else
        Browser->>DNS: 2. DNS查询(递归查询)
        DNS-->>Browser: 返回IP地址
        Browser->>Server: 3. TCP三次握手建立连接
        Browser->>Server: 4. 发送HTTP请求(GET /)
        alt 需要协商缓存
            Server->>Browser: 304 Not Modified
            Browser->>Browser: 使用本地缓存
        else
            Server->>Browser: 5. 返回HTTP响应(200 OK + HTML)
        end
        Browser->>Server: 6. 断开连接(TCP四次挥手)
    end
    Browser->>Browser: 7. 解析HTML构建DOM树
    Browser->>Browser: 8. 解析CSS构建CSSOM树
    Browser->>Browser: 9. 合并DOM和CSSOM生成Render树
    Browser->>Browser: 10. 布局计算(Layout/Reflow)
    Browser->>Browser: 11. 绘制(Painting)
    Browser->>RenderEngine: 12. 合成显示(Compositing)
    Browser-->>User: 页面显示完成

在支持mermaid预览的模型平台或者mermaid官网使用在线编辑器得到预览效果

使用模型绘制图无疑是非常方便的，但是小溪建议mermaid深度使用者还是要学点mermaid基本知识和语法，模型不是万能的，也不可能完全理解我们的需求，对mermaid有基本了解，我们可以更大的发挥模型的作用且不至于当模型陷入死循环时而束手无策。

官网示例

先看两个官方示例，感受一下mermaid的魅力。

rust 复制代码

sequenceDiagram
    participant Alice
    participant Bob
    Alice->>John: Hello John, how are you?
    loop HealthCheck
        John->>John: Fight against hypochondria
    end
    Note right of John: Rational thoughts<br/>prevail...
    John-->>Alice: Great!
    John->>Bob: How about you?
    Bob-->>John: Jolly good!

sql 复制代码

sequenceDiagram
    participant web as Web Browser
    participant blog as Blog Service
    participant account as Account Service
    participant mail as Mail Service
    participant db as Storage
    Note over web,db: The user must be logged in to submit blog posts
    web->>+account: Logs in using credentials
    account->>db: Query stored accounts
    db->>account: Respond with query result
    alt Credentials not found
        account->>web: Invalid credentials
    else Credentials found
        account->>-web: Successfully logged in
        Note over web,db: When the user is authenticated, they can now submit new posts
        web->>+blog: Submit new post
        blog->>db: Store post data
        par Notifications
            blog--)mail: Send mail to blog subscribers
            blog--)db: Store in-site notifications
        and Response
            blog-->>-web: Successfully posted
        end
    end

限制

全英文，需要一定英文阅读能力
免费套餐只能创建3个图
需要科学上网

优势

国内可用
有免费在线套餐

Mermaid

官网地址：mermaid.js.org/

在线编辑器

官网地址：mermaid.live/edit

Mermaid提供了Playground，只需在顶部打开【playground】切换到Playground即可

Playground提供了可视化编程和 AI对话两种模式并提供实时预览

|------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------|
| | |

文档地址

官网地址：mermaid.js.org/intro/

注册登录

注册登录Mermaid可创建持久化图项目

登录成功后即可进入Mermaid管理后台

产品定价

基本使用

Mermaid提供了丰富的图类型，除了我们平时常用的流程图外，还支持时序图、类图、甘特图等。

流程图

官网文档：mermaid.js.org/syntax/flow...

流程图连线

连线

css 复制代码

flowchart LR
    A --- B

单向箭头

css 复制代码

flowchart LR
    A --> B

连线文本

css 复制代码

flowchart LR
    A-- A到B ---B
或者

flowchart LR
    A---|A到B|B

箭头文本

css 复制代码

flowchart LR
    A-- A到B -->B
或者
flowchart LR
    A-->|A到B|B

虚线文本

css 复制代码

flowchart LR
    A -.A到B.-> B
或者    

flowchart LR
    A -.-> |A到B|B

连线动画

kotlin 复制代码

flowchart LR
  A e1@--> B
  e1@{ animate: true }

流程图的方向

css 复制代码

graph TD
    A --> B
    B --> C

graph：Mermaid 语法中定义流程图的关键词
TD：布局方向的缩写，表示流程图的布局是从上到下（Top-Down），同理可知其他方向类型：
- LR（Left-Right）：从左到右布局
- RL（Right-Left）：从右到左布局
- TB（Top-Bottom）：从上到下布局（与 TD 相同，只是另一种写法）
- BT（Bottom-Top）：从下到上布局（注意没有DT写法）

流程图方向不支持从下到上，如果这么写就会报错

也可以使用flowchart代替graph

流程图节点备注

流程图节点后面使用[]可以为节点添加备注

css 复制代码

flowchart LR
    A[这是A] --> B[这是B]

flowchart LR
    A["这是A"] --> B["这是B"]

流程图节点类型

流程图节点提供了很多类型的节点，这里展示一下常用的节点类型，详情的可查看流程图文档：mermaid.js.org/syntax/flow...

矩形节点

css 复制代码

flowchart LR
    A[这是A] --> B[这是B]

圆边节点

css 复制代码

flowchart LR
    A(这是A) --> B(这是B)

圆角节点

css 复制代码

flowchart LR
    A(这是A) --> B(这是B)

子例程节点

lua 复制代码

flowchart LR
    A[[这是A]] --> B[[这是B]]

圆柱形节点

css 复制代码

flowchart LR
    A[(这是A)] --> B[(这是B)]

条件节点

css 复制代码

flowchart TB
    A(这是A) --> B{这是B}

子流程图

子流程图节点语法如下，需要以end节点作为结束

arduino 复制代码

subgraph title
    graph definition
end

sql 复制代码

flowchart TB
   C1 --> A1
   subgraph one
    A1 --> A2
   end
   subgraph two
    C1 --> C2
   end

sql 复制代码

flowchart TB
   C1 --> A1
   subgraph one[这是第一个模块]
    A1 --> A2
   end
   subgraph two[这是第二个模块]
    C1 --> C2
   end

流程图节点事件

less 复制代码

flowchart LR
    A-->B
    B-->C
    C-->D
    D-->E
    click A "https://www.github.com" _blank
    click B "https://www.github.com" "Open this in a new tab" _blank
    click C href "https://www.github.com" _blank
    click D href "https://www.github.com" "Open this in a new tab" _blank

时序图

官网文档：mermaid.js.org/syntax/sequ...

时序图participant

rust 复制代码

sequenceDiagram
    Alice->>John: 实线箭头
    John-->>Alice: 虚线箭头
    Alice-)John: See you later!
sequenceDiagram
    participant Alice
    participant John
    Alice->>John: 实线箭头
    John-->>Alice: 虚线箭头
    Alice-)John: See you later!

时序图actor

less 复制代码

sequenceDiagram
    participant A as Alice
    participant J as John
    A->>J: 实线箭头
    J-->>A: 虚线箭头
    A-)J: See you later!

时序图别名

less 复制代码

sequenceDiagram
    participant A as Alice
    participant J as John
    A->>J: 实线箭头
    J-->>A: 虚线箭头
    A-)J: See you later!

时序图盒子

less 复制代码

 sequenceDiagram
    box pink Alice & John
    participant A
    participant J
    end
    box Another Group
    participant B
    participant C
    end
    A->>J: Hello John, how are you?
    J->>A: Great!
    A->>B: Hello Bob, how is Charley?
    B->>C: Hello Charley, how are you?

时序图活动

rust 复制代码

sequenceDiagram
    Alice->>John: Hello John, how are you?
    activate John
    John-->>Alice: Great!
    deactivate John
或者
sequenceDiagram
    Alice->>+John: Hello John, how are you?
    John-->>-Alice: Great!

时序图备注

sql 复制代码

sequenceDiagram
    create participant John
    Note right of John: Text in note

sql 复制代码

sequenceDiagram
    Alice->John: Hello John, how are you?
    Note over Alice,John: A typical interaction

类图

官网文档：mermaid.js.org/syntax/clas...

创建类图

yaml 复制代码

classDiagram
    Animal : +int age
    Animal : +String gender
    Animal: +isMammal()
    Animal: +mate()

类图继承

scss 复制代码

classDiagram
    Animal : +int age
    Animal : +String gender
    Animal: +isMammal()
    Animal: +mate()
    note for Duck "can fly\ncan swim\ncan dive\ncan help in debugging"
    Animal <|-- Duck
    class Duck{
        +String beakColor
        +swim()
        +quack()
    }
    Animal <|-- Fish
    class Fish{
        -int sizeInFeet
        -canEat()
    }

类图类型定义

csharp 复制代码

classDiagram
    class Square~Shape~{
        int id
        List~int~ position
        setPoints(List~int~ points)
        getPoints() List~int~
    }
    Square : -List~string~ messages
    Square : +setMessages(List~string~ messages)
    Square : +getMessages() List~string~
    Square : +getDistanceMatrix() List~List~int~~

c 复制代码

classDiagram
    class BankAccount {
        int id
        string name
    }
    BankAccount : +owner() string
    BankAccount : +deposit(amount)
    BankAccount : +withdrawal(amount)

状态图

官网文档：mermaid.js.org/syntax/stat...

状态图开始与结束

状态图中使用[*]表示开始与结束节点

lua 复制代码

stateDiagram
    [*] --> Still
    Still --> [*]
    Still --> Moving
    Moving --> Still
    Moving --> Crash
    Crash --> [*]

状态图备注

lua 复制代码

stateDiagram
    Still --> Moving: 从still到moving

状态图复合模式

css 复制代码

stateDiagram
    [*] --> First
    state First {
        [*] --> second
        second --> [*]
    }
    [*] --> NamedComposite
    NamedComposite: Another Composite
    state NamedComposite {
        [*] --> namedSimple
        namedSimple --> [*]
        namedSimple: Another simple
    }

sql 复制代码

stateDiagram
    [*] --> First
    state First {
        [*] --> Second
        state Second {
            [*] --> Third
            Third --> [*]
        }
    }

sql 复制代码

stateDiagram
    [*] --> First
    First --> Second
    First --> Third
    state First {
        [*] --> fir
        fir --> [*]
    }
    state Second {
        [*] --> sec
        sec --> [*]
    }
    state Third {
        [*] --> thi
        thi --> [*]
    }

状态图选择

lua 复制代码

stateDiagram
    state if_state <<choice>>
    [*] --> IsPositive
    IsPositive --> if_state
    if_state --> False: if n < 0
    if_state --> True : if n >= 0

状态图分支

sql 复制代码

stateDiagram
    state fork_state <<fork>>
    [*] --> fork_state
    fork_state --> State2
    fork_state --> State3
    state join_state <<join>>
    State2 --> join_state
    State3 --> join_state
    join_state --> State4
    State4 --> [*]

实体关系图

官网文档：mermaid.js.org/syntax/enti...

实体关系图一对多

o{和}o：表示0或多个
}|和|{：表示至少至少一个

css 复制代码

erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE-ITEM: contains
    CUSTOMER }|..|{ DELIVERY-ADDRESS : uses

css 复制代码

erDiagram
    CAR ||--o{ NAMED-DRIVER : allows
    PERSON }o..o{ NAMED-DRIVER : is

实体关系图属性

c 复制代码

erDiagram
    CUSTOMER ||--o{ ORDER : places
    CUSTOMER {
        string name
        string custNumber
        string sector
    }
    ORDER ||--|{ LINE-ITEM: contains
    ORDER {
        int orderNumber
        string deliveryAddress
    }
    LINE-ITEM {
        string productCode
        int quantity
        float pricePerUnit
    }
    CUSTOMER }|..|{ DELIVERY-ADDRESS : uses

甘特图

官网文档：mermaid.js.org/syntax/gant...

甘特图基本用法

less 复制代码

gantt
    title A Gantt Diagram
    dateFormat YYYY-MM-DD
    section Section
        A task          :a1, 2014-01-01, 30d
        Another task    :after a1, 20d
    section Another
        Task in Another :2014-01-12, 12d
        another task    :24d

甘特图里程碑

arduino 复制代码

gantt
    dateFormat HH:mm
    axisFormat %H:%M
    Initial milestone : milestone, m1, 17:49, 2m
    Task A : 10m
    Task B : 5m
    Final milestone : milestone, m2, 18:08, 4m

饼图

官网文档：mermaid.js.org/syntax/pie....

饼图基本用法

csharp 复制代码

pie title Pets adopted by volunteers
    "Dogs" : 386
    "Cats" : 85
    "Rats" : 15

饼图展示数据

csharp 复制代码

pie showData
    title Pets adopted by volunteers
    "Dogs" : 386
    "Cats" : 85
    "Rats" : 15

饼图样式调整

csharp 复制代码

%%{init: {"pie": {"textPosition": 0.5}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
pie showData
    title Key elements in Product X
    "Calcium" : 42.96
    "Potassium" : 50.05
    "Magnesium" : 10.01
    "Iron" :  5

思维导图

官网文档：mermaid.js.org/syntax/mind...

scss 复制代码

mindmap
  root((mindmap))
    Origins
      Long history
      ::icon(fa fa-book)
      Popularisation
        British popular psychology author Tony Buzan
    Research
      On effectiveness<br/>and features
      On Automatic creation
        Uses
            Creative techniques
            Strategic planning
            Argument mapping
    Tools
      Pen and paper
      Mermaid

时间线图

官网文档：mermaid.js.org/syntax/time...

时间线图基本用法

yaml 复制代码

timeline
    title History of Social Media Platform
    2002 : LinkedIn
    2004 : Facebook
         : Google
    2005 : YouTube
    2006 : Twitter

多级时间线图

less 复制代码

timeline
    title Timeline of Industrial Revolution
    section 17th-20th century
        Industry 1.0 : Machinery, Water power, Steam <br>power
        Industry 2.0 : Electricity, Internal combustion engine, Mass production
        Industry 3.0 : Electronics, Computers, Automation
    section 21st century
        Industry 4.0 : Internet, Robotics, Internet of Things
        Industry 5.0 : Artificial intelligence, Big data, 3D printing

UML图

官网文档：mermaid.js.org/syntax/zenu...

UML图基本使用

rust 复制代码

zenuml
    title Demo
    Alice->John: Hello John, how are you?
    John->Alice: Great!
    Alice->John: See you later!

UML图角色

scss 复制代码

zenuml
    title Annotators
    @Actor Alice
    @Database Bob
    Alice->Bob: Hi Bob
    Bob->Alice: Hi Alice

UML图嵌套

css 复制代码

zenuml
    A.method() {
      B.nested_sync_method()
      B->C: nested async message
    }

XY图

官网文档：mermaid.js.org/syntax/xyCh...

yaml 复制代码

xychart-beta
    title "Sales Revenue"
    x-axis [jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec]
    y-axis "Revenue (in $)" 4000 --> 11000
    bar [5000, 6000, 7500, 8200, 9500, 10500, 11000, 10200, 9200, 8500, 7000, 6000]
    line [5000, 6000, 7500, 8200, 9500, 10500, 11000, 10200, 9200, 8500, 7000, 6000]

方框图

官网文档：mermaid.js.org/syntax/bloc...

动态布局

less 复制代码

block-beta
  columns 3
  a:3
  block:group1:2
    columns 2
    h i j k
  end
  g
  block:group2:3
    %% columns auto (default)
    l m n o p q r
  end

箭头

scss 复制代码

block-beta
  blockArrowId<["Label"]>(right)
  blockArrowId2<["Label"]>(left)
  blockArrowId3<["Label"]>(up)
  blockArrowId4<["Label"]>(down)
  blockArrowId5<["Label"]>(x)
  blockArrowId6<["Label"]>(y)

边框样式

scss 复制代码

block-beta
    columns 1
        db(("DB"))
        blockArrowId<["&nbsp;&nbsp;&nbsp;"]>(down)
        block:ID
            A
            B["A wide one in the middle"]
            C
        end
        space
        D
        ID --> D
        C --> D
        style B fill:#939,stroke:#333,stroke-width:4px

系统架构

css 复制代码

block-beta
  columns 3
  Frontend blockArrowId6<[" "]>(right) Backend
  space:2 down<[" "]>(down)
  Disk left<[" "]>(left) Database[("Database")]
  classDef front fill:#696,stroke:#333;
  classDef back fill:#969,stroke:#333;
  class Frontend front
  class Backend,Database back

看板图

官网文档：mermaid.js.org/syntax/kanb...

css 复制代码

kanban
  Todo
    [Create Documentation]
    docs[Create Blog about the new diagram]
  [In progress]
    id6[Create renderer so that it works in all cases. We also add som extra text here for testing purposes. And some more just for the extra flare.]
  id9[Ready for deploy]
    id8[Design grammar]@{ assigned: 'knsv' }
  id10[Ready for test]
    id4[Create parsing tests]@{ ticket: MC-2038, assigned: 'K.Sveidqvist', priority: 'High' }
    id66[last item]@{ priority: 'Very Low', assigned: 'knsv' }
  id11[Done]
    id5[define getData]
    id2[Title of diagram is more than 100 chars when user duplicates diagram with 100 char]@{ ticket: MC-2036, priority: 'Very High'}
    id3[Update DB function]@{ ticket: MC-2037, assigned: knsv, priority: 'High' }
  id12[Can't reproduce]
    id3[Weird flickering in Firefox]

友情提示

见原文：AI很方便，不过我还是建议学点Mermaid基础

本文同步自微信公众号 "程序员小溪" ，这里只是同步，想看及时消息请移步我的公众号，不定时更新我的学习经验。