有没有会的小伙伴解答一下，急

3和4可能是我理解不好 首先你创建一个CPU的类 然后private int speed; idea的话alt + insert 就可以出现一个getter and setter 然后下一步下一步就完事了 再用alt + insert 有一个Constructor 点一下就生成了构造方法 有参数的构造方法和无参数的构造方法都要有 这样CPU就创建好了 HandDisk同理 也是按照CPU的这一段来进行 只不过private int speed;变成了private int amount;
然后是PC主方法 这个我给你贴一下代码吧 前边的你要自己去试一下
public class PC {

public static void main(String[] args) {
    CPU cpu = new CPU();
    cpu.setSpeed(2200);
    HandDisk disk = new HandDisk();
    disk.setAmount(200);
    PC pc = new PC();
    pc.setCPU(cpu);
    pc.setHandDisk(disk);
    pc.show();
}
 private int show(){
    return CPU.getSpeed();
}
private void setCPU(CPU c){
    new CPU(c);
}
private void setHandDisk(HandDisk h){
    new HandDisk(h);
}

}

代码如下：

public class CPU {

    private int speed;

    public int getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

public class HardDisk {

    private int amount;

    public int getAmount() {
        return amount;
    }

    public void setAmount(int amount) {
        this.amount = amount;
    }
}

public class PC {

    private CPU cpu;
    private HardDisk HD;

    public void setCPU(CPU cpu) {
        this.cpu = cpu;
    }

    public void setHardDisk(HardDisk HD) {
        this.HD = HD;
    }

    public void show(){
        System.out.println("CPU速度：" + cpu.getSpeed() + "\t\t磁盘容量：" + HD.getAmount());
    }
}

public class Test {

    public static void main(String[] args) {

        CPU cpu = new CPU();
        cpu.setSpeed(2200);

        HardDisk disk = new HardDisk();
        disk.setAmount(200);

        PC pc = new PC();
        pc.setCPU(cpu);
        pc.setHardDisk(disk);

        pc.show();
    }
}