Java接口不能实例化吗?
部分代码如下,标红的部分,不太理解
public interface ICommand {
void command();
}
public class CommandOpen implements ICommand{
@Override
public void command() {
// TODO Auto-generated method stub
TV.createTvInstance().open();
}
}
public class CommandClose implements ICommand{
@Override
public void command() {
// TODO Auto-generated method stub
TV.createTvInstance().close();
}
}
public class CommandChangeChannel implements ICommand{
@Override
public void command() {
// TODO Auto-generated method stub
TV.createTvInstance().changeChannel();
}
}
public class Controller {
// 将该类原本的CommandOpen换成ICommand, CommandClose换成ICommand, CommandChangeChannel换成ICommand也可以编译通过并运行结果无误
ICommand cmdOpen;
ICommand cmdClose;
ICommand cmdchange;
// 初始化传进来的是new出来的对象,这种方式不是实例化接口吗?
Controller(ICommand cmdOpen, ICommand cmdClose, ICommand cmdchange)
{
this.cmdOpen = cmdOpen;
this.cmdClose = cmdClose;
this.cmdchange = cmdchange;
}
public void open()
{
cmdOpen.command();
}
public void close()
{
cmdClose.command();
}
public void changeChannel()
{
cmdchange.command();
}
}
public class TV {
private static TV sTv;
public void open()
{
System.out.print("open tv. \n");
}
public void close()
{
System.out.print("close tv. \n");
}
public void changeChannel()
{
System.out.print("change tv. \n");
}
private TV()
{
}
public static TV createTvInstance()
{
if (sTv == null)
sTv = new TV();
return sTv;
}
}
public class Client {
public static void main(String[] args) {
CommandOpen cmdOpen = new CommandOpen();
CommandClose cmdClose = new CommandClose();
CommandChangeChannel cmdchange = new CommandChangeChannel();
Controller c = new Controller(cmdOpen, cmdClose, cmdchange);
c.open();
c.close();
c.changeChannel();
}
}