14.面向对象应用

• 客户的第一次需求：开发一个打印机控制程序
• 客户的第二次需求：两个打印机的选择程序

1. classPrinter{
2. void open(){
3. System.out.println("open");
4. }
6. void close(){
7. System.out.println("close");
8. }
10. void print(String s){
11. System.out.println("print-->"+ s);
12. }
13. }

1. classHPPrinter extends Printer{
2. }

1. classCanonPrinter extends Printer{
3. void close(){
4. this.clean();
5. super.close();
6. }
8. void clean(){
9. System.out.println("clean");
10. }
11. }

1. classTest{
2. publicstaticvoid main(String args []){
3. int flag =1;
5. if(flag ==0){
6. HPPrinter hpPrinter =newHPPrinter();
7. hpPrinter.open();
8. hpPrinter.print("abc");
9. hpPrinter.close();
10. }
11. elseif(flag ==1){
12. CanonPrinter canonPrinter =newCanonPrinter();
13. canonPrinter.open();
14. canonPrinter.print("123");
15. canonPrinter.close();
16. }
17. }
18. }

来自为知笔记(Wiz)