1.案例

2.代码实现

面向过程

import java.util.Scanner;/*** Procedure Oriented Programming 面向过程编程*/public class POP {public static void main(String[] args) {Scanner sc = new Scanner(System.in);while(true){System.out.println("1.学生成绩管理");System.out.println("2.学生选修管理");System.out.println("3.退出系统");System.out.println("请选择:");int input = sc.nextInt();if(input == 1){outer:while(true){System.out.println("1.增加成绩");System.out.println("2.修改成绩");System.out.println("3.删除成绩");System.out.println("4.增加查询成绩");System.out.println("5.返回主菜单");System.out.println("请选择菜单编号");int  order = sc.nextInt();switch(order){case 1 :System.out.println("你选择了增加成绩");break;case 2 :System.out.println("你选择了修改成绩");break;case 3 :System.out.println("你选择了删除成绩");break;case 4 :System.out.println("你选择了查询成绩");break;case 5 :break outer;}}}else if(input ==2){System.out.println("你选择了选课系统");}else{System.out.println("感谢使用XX系统");break;}}}
}

面向对象

分析：

a.该过程涉及到的对象（事物）有两个：用户和菜单

b.用户拥有执行增删改查的动作

public class Menu {public int order;//编号public String name;public Menu(int order,String name){this.order=order;this.name=name;}public void show(){System.out.println(order + "." + name);}
}

public class User {public void addScore(){System.out.println("你选择了增加成绩");}public void deleteScore(){System.out.println("你选择了删除成绩");}public void updateScore(){System.out.println("你选择了修改成绩");}public void searchScore(){System.out.println("你选择了查询成绩");}
}

import java.util.Scanner;/*** Object Oriented Programming 面对对象编程*/
public class OOP {public static Menu[] mainMenus = {new Menu(1,"学生成绩管理"),new Menu(2,"学生选课管理"),new Menu(3,"退出系统")};public static Menu[] secondMenus = {new Menu(1,"增加成绩"),new Menu(2,"修改成绩"),new Menu(3,"删除成绩"),new Menu(4,"查询成绩"),new Menu(5,"返回主菜单")};public static Scanner sc = new Scanner(System.in);public static User user = new User();public static void main(String[] args) {gotoMain();}//去主菜单public static void gotoMain(){showMenus(mainMenus);//显示主菜单int number = sc.nextInt();if(number == 1){gotoSecond();}else if(number == 2){System.out.println("你选择了学生选课管理");gotoMain();//去主菜单}else{System.out.println("感谢使用XX系统");}}//去二级菜单public static void gotoSecond(){showMenus(secondMenus);//显示二级菜单int order = sc.nextInt();switch(order){case 1:user.addScore();//用户增加成绩gotoSecond();break;case 2:user.updateScore();//用户修改成绩gotoSecond();break;case 3:user.deleteScore();//用户删除成绩gotoSecond();break;case 4:user.searchScore();//用户查询成绩gotoSecond();break;case 5:gotoMain();break;}}public static void showMenus(Menu[] menus){for(int i=0;i<menus.length;i++){menus[i].show();;}System.out.println("请选择菜单编号:");}
}

对比

面向过程侧重点在过程的实现上。面向对象的侧重点在对象上，需要利用对象的行为来完成过程的组装。