title: "Model-View-Controller Pattern in Java: Streamlining Java Web Development" shortTitle: Model-View-Controller (MVC) description: "Learn about the Model-View-Controller (MVC) design pattern in Java, including its benefits, real-world examples, use cases, and how to implement it effectively in your applications." category: Architectural language: en tag:
To separate an application into three interconnected components (Model, View, Controller), enabling modular development of each part independently, enhancing maintainability and scalability. Model-View-Controller (MVC) design pattern is widely used in Java applications for web development and user interface separation.
Real-world example
Consider ICU room in a hospital displaying patient health information on devices taking input from sensors. The display shows data received from the controller, which updates from the sensor model. This exemplifies the MVC design pattern in a real-world Java application.
In plain words
MVC separates the business logic from user interface by mediating Controller between Model & View.
Wikipedia says
Model–view–controller (MVC) is commonly used for developing user interfaces that divide the related program logic into three interconnected elements. This is done to separate internal representations of information from the ways information is presented to and accepted from the user.
Consider following GiantModel
model class that provides the health, fatigue & nourishment information.
@Getter
@Setter
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class GiantModel {
private Health health;
private Fatigue fatigue;
private Nourishment nourishment;
@Override
public String toString() {
return String.format("The giant looks %s, %s and %s.", health, fatigue, nourishment);
}
}
GiantView
class to display received patient data.
public class GiantView {
public void displayGiant(GiantModel giant) {
LOGGER.info(giant.toString());
}
}
GiantController
class takes updates from GiantModel
and sends to GiantView
for display.
public class GiantController {
private final GiantModel giant;
private final GiantView view;
public GiantController(GiantModel giant, GiantView view) {
this.giant = giant;
this.view = view;
}
@SuppressWarnings("UnusedReturnValue")
public Health getHealth() {
return giant.getHealth();
}
public void setHealth(Health health) {
this.giant.setHealth(health);
}
@SuppressWarnings("UnusedReturnValue")
public Fatigue getFatigue() {
return giant.getFatigue();
}
public void setFatigue(Fatigue fatigue) {
this.giant.setFatigue(fatigue);
}
@SuppressWarnings("UnusedReturnValue")
public Nourishment getNourishment() {
return giant.getNourishment();
}
public void setNourishment(Nourishment nourishment) {
this.giant.setNourishment(nourishment);
}
public void updateView() {
this.view.displayGiant(giant);
}
}
This example demonstrates how the MVC pattern separates concerns in a Java application, making it easier to manage and update components independently.
Benefits:
Trade-offs: