java程序及类图实例

以下是一个简单的Java程序和类图示例：

Java程序：

public class Car {
    private String brand;
    private String color;
    private int year;
    
    public Car(String brand, String color, int year) {
        this.brand = brand;
        this.color = color;
        this.year = year;
    }
    
    public void start() {
        System.out.println("The " + color + " " + brand + " starts.");
    }
    
    public void stop() {
        System.out.println("The " + color + " " + brand + " stops.");
    }
    
    public int getYear() {
        return year;
    }
    
    public void setYear(int year) {
        this.year = year;
    }
}

public class Main {
    public static void main(String[] args) {
        Car myCar = new Car("Toyota", "blue", 2020);
        myCar.start();
        myCar.stop();
        
        System.out.println("My car's year is " + myCar.getYear());
        myCar.setYear(2021);
        System.out.println("My car's year is now " + myCar.getYear());
    }
}

类图示例：

+------------------+          +-------+
|       Car        |          |  Main |
+------------------+          +-------+
| - brand: String   |          |       |
| - color: String   |          |       |
| - year: int       |          |       |
+------------------+          |       |
| + start(): void   |          |       |
| + stop(): void    |          |       |
| + getYear(): int  |          |       |
| + setYear(int): void       |       |
+------------------+          +-------+

在这个例子中，Car类表示汽车的一些属性和操作，例如品牌，颜色，年份等。Main类是程序的主类，包含了main方法，用于创建Car对象并调用其方法。类图描述了Car和Main类之间的关系，包括类名，属性和方法。