用java设计一组类，分别表示计算机，台式机，笔记本，服务器

好的，为您设计一组 Java 类：

public class Computer {
    private String brand;
    private String model;

    public Computer(String brand, String model) {
        this.brand = brand;
        this.model = model;
    }

    public void turnOn() {
        System.out.println("Computer is turning on...");
    }

    public void turnOff() {
        System.out.println("Computer is turning off...");
    } 
}

public class Desktop extends Computer {
    private String monitor;

    public Desktop(String brand, String model, String monitor) {
        super(brand, model);
        this.monitor = monitor;
    }

    public void playGame() {
        System.out.println("Playing game on desktop...");
    }
}

public class Laptop extends Computer {
    private double weight;

    public Laptop(String brand, String model, double weight) {
        super(brand, model);
        this.weight = weight;
    }

    public void carryAround() {
        System.out.println("Carrying laptop around...");
    }
}

public class Server extends Computer {
    private boolean rackMounted;

    public Server(String brand, String model, boolean rackMounted) {
        super(brand, model);
        this.rackMounted = rackMounted;
    }

    public void processRequests() {
        System.out.println("Processing requests on server...");
    }
}

以上是一个简单的类设计，其中 `Computer` 是基类，其他三个类都继承自它。`Desktop`、`Laptop`、`Server` 分别表示台式机、笔记本和服务器，它们都有一些特殊的属性和方法。您可以在此基础上进一步扩展和优化。