程序员难免要经常画流程图，状态图，时序图等。以前经常用 visio
画，经常为矩形画多大，摆放在哪等问题费脑筋。有时候修改文字后，为了较好的显示效果不得不再去修改图形。今天介绍的工具是如何使用
PlantUML 的插件画流程图，状态图，时序图等。这是一种程序员看了就会爱上的画图方式：自然，高效。

什么是 PlantUML

PlantUML 是一个画图脚本语言，用它可以快速地画出：

• 类图：http://plantuml.com/class-diagram
• 流程图：http://plantuml.com/activity-diagram-beta
• 时序图：http://plantuml.com/sequence-diagram
• 用例图：http://plantuml.com/use-case-diagram
• 状态图：http://plantuml.com/state-diagram
• 组件图：http://plantuml.com/component-diagram

1. 类图

案例1：

 @startuml

abstract class AbstractList
abstract AbstractCollection
interface List
interface Collection

List <|-- AbstractList
Collection <|-- AbstractCollection

Collection <|- List
AbstractCollection <|- AbstractList
AbstractList <|-- ArrayList

class ArrayList {
Object[] elementData
size()
}

enum TimeUnit {
DAYS
HOURS
MINUTES
}

@enduml

案例2：

@startuml
class Track
class Media
class Trip{
   String tripID;
   String tracks;
   String medias;
}
Trip --> Track
Trip --> Media

interface ITripTrackCollection{
    void start();
    void stop();
    void pause();
    void destory();
}
class TripTrackCollection implements ITripTrackCollection{
    Vector<LocationInfo> mLocations;
    ExtcutorService mVecoterThread;
    ScheduledExecutorService mDatabaseThread;
}

class TrackCollectService extends Service implements ITripTrackCollection{
    TripTrackCollection TripTrackCollection;
}
TrackCollectService -->TripTrackCollection
@enduml

2. 流程图

案例1：

@startuml
(*)  --> "check input"
If "input is verbose" then
--> [Yes] "turn on verbosity"
--> "run command"
else
--> "run command"
Endif
-->(*)
@enduml

案例2：

start
:"步骤1处理";
:"步骤2处理";
if ("条件1判断") then (true)
    :条件1成立时执行的动作;
    if ("分支条件2判断") then (no)
        :"条件2不成立时执行的动作";
    else
        if ("条件3判断") then (yes)
            :"条件3成立时的动作";
        else (no)
            :"条件3不成立时的动作";
        endif
    endif
    :"顺序步骤3处理";
endif

if ("条件4判断") then (yes)
:"条件4成立的动作";
else
    if ("条件5判断") then (yes)
        :"条件5成立时的动作";
    else (no)
        :"条件5不成立时的动作";
    endif
endif
stop
@enduml

3.时序图

案例1：

@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
@enduml

案例2：

@startuml
title Android Broadcast procedure
participant Activity #Lime
participant ContextWrapper #Cyan
participant ContextImpl #Cyan
participant ActivityManagerService #Cyan
participant ActivityStackSupervisor #Cyan
participant ActivityStack #Cyan
participant ApplicationThreadProxy #Silver
participant InnerReceiver #Magenta
participant ReceiverDispatcher #Magenta
participant BroadcastReceiver #Magenta

autonumber
Activity -> ContextWrapper : registerReceiver()
ContextWrapper -> ContextImpl : registerReceiver()
ContextImpl -> LoadedApk : getReceiverDispatcher()
LoadedApk -> ActivityManagerProxy : registerReceiver()
ActivityManagerProxy -> ActivityManagerService : registerReceiver()

Activity -> ContextWrapper : sendBroadcast()
ContextWrapper -> ContextImpl : sendBroadcast()
ContextImpl -> ActivityManagerService: broadcastIntent()
ActivityManagerService -> ActivityManagerService : broadcastIntentLocked()
ActivityManagerService -> ActivityManagerService : collectReceiverComponents()
ActivityManagerService -> ActivityManagerService : scheduleBroadcastsLocked()
ActivityManagerService -> ActivityManagerService : processNextBroadcast()
ActivityManagerService -> ActivityManagerService : deliverToRegisteredReceiverLocked()
ActivityManagerService -> ActivityManagerService : performReceiveLocked()
ActivityManagerService -> ApplicationThreadProxy : scheduleRegisteredReceiver()
ApplicationThreadProxy -> InnerReceiver : performReceive()
InnerReceiver -> ReceiverDispatcher : performReceive()
ReceiverDispatcher -> BroadcastReceiver : onReceive()

Activity -> ContextWrapper : sendOrderedBroadcast()
ContextWrapper -> ContextImpl : sendOrderedBroadcast()
ContextImpl -> ActivityManagerService: broadcastIntent()
@enduml

4. 用例图：

@startuml
:Main Admin: as Admin
(Use the application) as (Use)

User -> (Start)
User --> (Use)

Admin ---> (Use)

note right of Admin : This is an example.

note right of (Use)
A note can also
be on several lines
end note

note "This note is connected\nto several objects." as N2
(Start) .. N2
N2 .. (Use)
@enduml

5. 状态图

@startuml
scale 350 width
[*] --> NotShooting

state NotShooting {
  [*] --> Idle
  Idle --> Configuring : EvConfig
  Configuring --> Idle : EvConfig
}

state Configuring {
  [*] --> NewValueSelection
  NewValueSelection --> NewValuePreview : EvNewValue
  NewValuePreview --> NewValueSelection : EvNewValueRejected
  NewValuePreview --> NewValueSelection : EvNewValueSaved

  state NewValuePreview {
     State1 -> State2
  }

}
@enduml

6. 组件图

案例1：

@startuml

package "Some Group" {
HTTP - [First Component]
[Another Component]
}

package "Other Groups" {
FTP - [Second Component]

[First Component] --> FTP
}

@enduml

案例2：

@startuml

package "组件1" {
    ["组件1.1"] - ["组件1.2"]
    ["组件1.2"] -> ["组件2.1"]
}

node "组件2" {
    ["组件2.1"] - ["组件2.2"]
    ["组件2.2"] --> [负载均衡服务器]
}

cloud {
    [负载均衡服务器] -> [逻辑服务器1]
    [负载均衡服务器] -> [逻辑服务器2]
    [负载均衡服务器] -> [逻辑服务器3]
}

database "MySql" {
    folder "This is my folder" {
        [Folder 3]
    }

    frame "Foo" {
        [Frame 4]
    }
}

[逻辑服务器1] --> [Folder 3]
[逻辑服务器2] --> [Frame 4]
[逻辑服务器3] --> [Frame 4]

@enduml