如何打印界面的连接方法?我想通过最小化类修改来修改电源。
如果我使用arr [0] .connect();错误:对于类型Device,方法connect()未定义
public class main{
private static Device arr[];
public static void main(String[] args) {
// TODO Auto-generated method stub
init();
arr[0].print();
arr[1].print();
}
public static void init() {
arr = new Device[2];
arr[0] = new Printer();
arr[1] = new UsbMem();
}
}
public interface Connectable {
public static final String name = ":USB";
public abstract void connect();
}
public abstract class Device {
public abstract void print();
}
public class Printer extends Device implements Connectable {
public void print() {
System.out.println("It's a printer");
}
public void connect() {
System.out.println(name + "connect with printer");
}
}
public class UsbMem extends Device implements Connectable {
public void print() {
System.out.println("USB memory");
}
public void connect() {
System.out.println(name + "connect with usb memory");
}
}
这是一台打印机。 :USB连接打印机USB存储器:USB连接USB存储器
Device
需要实施Connectable
。
public class Main {
private static Device arr[];
public static void main(String[] args) {
// TODO Auto-generated method stub
init();
arr[0].print();
arr[1].print();
}
public static void init() {
arr = new Device[2];
arr[0] = new Printer();
arr[1] = new UsbMem();
}
}
public interface Connectable {
public static final String name = ":USB";
public abstract void connect();
}
public abstract class Device implements Connectable {
public abstract void print();
}
public class Printer extends Device {
public void print() {
System.out.println("It's a printer");
}
public void connect() {
System.out.println(name + "connect with printer");
}
}
public class UsbMem extends Device {
public void print() {
System.out.println("USB memory");
}
public void connect() {
System.out.println(name + "connect with usb memory");
}
}
将对象转换为Connectable
((Connectable)arr[0]).connect()