How to Install and Use PlantUML in IntelliJ IDEA for Quick Diagramming

PlantUML is an open‑source textual language that lets you create a variety of UML and non‑UML diagrams (sequence, use‑case, class, activity, component, state, object, deployment, Gantt, architecture, etc.) quickly and export them as PNG or SVG.

Advantages

All‑text editing, no drag‑and‑drop controls.

Platform‑independent – any system with the PlantUML JAR can generate diagrams.

Integrates with many editors and IDEs, including IntelliJ IDEA.

Prerequisite: Graphviz

PlantUML relies on Graphviz for rendering. Install Graphviz from the official site (or a trusted package manager) before using PlantUML; otherwise diagrams will not display.

Installing the PlantUML plugin in IntelliJ IDEA

Open File → Settings → Plugins .

Search for PlantUML and click Install (PlantUML Integration).

Restart IDEA.

For offline installation, download the plugin zip from

http://plugins.jetbrains.com/plugin/7017-plantuml-integration

and install it via the Install Plugin from Disk option.

Creating a PlantUML file

Choose File → New → PlantUML File and select the diagram type you want to create.

Sample PlantUML script

@startuml
skinparam rectangle {
  BackgroundColor DarkSeaGreen
  FontStyle Bold
  FontColor DarkGreen
}
:User: as u
rectangle Tool as t
rectangle "Knowledge Base" as kb
(Robot Framework) as rf
(DUT) as dut
note as ts
  - Execute test script,
  - Respond using knowledge base,
  - Follow public account: Java后端
end note
note as act
  - Query &
  - Action
end note
note as kb_cmt
  - Determine response method,
  - Fill message from context,
  - Save info to context
end note
u --> rf
rf --> ts
ts --> t
kb <-> act
act --> t
t = dut
t_cmt -- t
kb_cmt -left- kb
@enduml

Sequence diagram example

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

Defining roles in a sequence diagram

@startuml
actor Foo1
boundary Foo2
control Foo3
entity Foo4
database Foo5
collections Foo6
Foo1 -> Foo2: To boundary
Foo1 -> Foo3: To control
Foo1 -> Foo4: To entity
Foo1 -> Foo5: To database
Foo1 -> Foo6: To collections
@enduml

Exporting diagrams

After the diagram renders in IDEA, you can export it as PNG, SVG, or other formats via the PlantUML tool window.

Alternative: Chrome PlantUML Viewer

If you prefer not to install Graphviz, you can use the Chrome extension "PlantUML Viewer" to edit PlantUML text and view diagrams directly in the browser.