把這幾天學的做一個綜合性應用，做了一個小型訂餐的系統，用到了面向物件的思想、靜態的特性、集合框架中的ArrayList和HashMap對物件的儲存以及操作、異常處理。

專案總共包含四個檔案，分別是選單類、訂單類、操作類、Main

選單資訊儲存與操作

/**
 * Created by zhangshuo on 2018/7/26.
 * 外層類是選單列表
 * 內層類儲存單品資訊
 */
import java.util.*;
public class Cookbook {

    public Cookbook() {
        setlist();
        setmap();
    }

    public
 
 class Cook{
        String name;
        int type;
        double price;
        int like=0;

        public Cook() {

        }

        public Cook(String name, int type, double price) {
            this.name = name;
            this.type = type;
            this.price = price;
        }

        public
 
 String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getType() {
            return type;
        }

        public void setType(int type) {
            this.type = type;
        }

        public
 
 double getPrice() {
            return price;
        }

        public void setPrice(double price) {
            this.price = price;
        }

        public int getLike() {
            return like;
        }

        public void setLike() {
            like++;
        }
    }

    public static List list=new ArrayList();

    void setlist(){
        Cook c1=new Cook("魚香肉絲",1,22);list.add(c1);
        Cook c2=new Cook("麻辣雞絲",1,20);list.add(c2);
        Cook c3=new Cook("京醬肉絲",1,26);list.add(c3);
        Cook c4=new Cook("西葫蘆絲",2,13);list.add(c4);
        Cook c5=new Cook("炒土豆絲",2,10);list.add(c5);
        Cook c6=new Cook("牛肉餅",3,6);list.add(c6);
        Cook c7=new Cook("豬肉包",3,2);list.add(c7);
        Cook c8=new Cook("皮蛋湯",4,5);list.add(c8);
        Cook c9=new Cook("百事可樂",5,5);list.add(c9);
        Cook c10=new Cook("青島啤酒",5,6);list.add(c10);
    }

    public static Map hsmap=new HashMap();

    public static void setmap(){       //把金額與名稱對映
        Iterator it=list.iterator();
        int i=0;
        while(it.hasNext()){
            Cook cook=(Cook)it.next();
            hsmap.put(cook.getName(),i);
            i++;
        }
    }

    public static void showall(){
        System.out.println("選單");
        Iterator it=list.iterator();
        System.out.println("菜名"+"\t\t\t\t"+"價格"+"\t\t"+"型別"+"\t\t"+"贊數");
        while(it.hasNext()){
            Cook c=(Cook)it.next();
            System.out.print(c.name+"\t\t\t"+c.price+"\t\t");
            switch(c.type){
                case 1:System.out.print("葷");break;
                case 2:System.out.print("素");break;
                case 3:System.out.print("主");break;
                case 4:System.out.print("湯");break;
                case 5:System.out.print("飲");break;
            }
            System.out.println("\t\t"+c.like);
        }
    }
}

訂單的資訊儲存與操作

/**
 * Created by zhangshuo on 2018/7/26.
 * 外層類是訂單列表
 * 內層類是單個訂單
 */
import java.util.*;
public class Orderlist {

    public class order{
        String name;        //人名
        String cookname;    //菜名
        int n;              //購買數量
        String time;           //購買時間
        String place;       //收貨地點
        double nprice=0;         //總價
        String state="未簽收";       //狀態

        public order(String name, String cookname, int n, String time, String place) {  //生成訂單
            this.name = name;
            this.cookname = cookname;
            this.n = n;
            this.time = time;
            this.place = place;
            Cookbook.Cook c=(Cookbook.Cook)Cookbook.list.get((int)Cookbook.hsmap.get(cookname));//到選單中查詢相應菜
            this.nprice=n*c.price;//獲取名字所在行的價格
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getCookname() {
            return cookname;
        }

        public void setCookname(String cookname) {
            this.cookname = cookname;
        }

        public int getN() {
            return n;
        }

        public void setN(int n) {
            this.n = n;
        }

        public String getTime() {
            return time;
        }

        public void setTime(String time) {
            this.time = time;
        }

        public String getPlace() {
            return place;
        }

        public void setPlace(String place) {
            this.place = place;
        }

        public double getNprice() {
            return nprice;
        }

        public void setNprice(double nprice) {
            this.nprice = nprice;
        }

        public String getState() {
            return state;
        }

        public void setState(String state) {
            this.state = state;
        }
    }

    List olist=new ArrayList();

    public Orderlist() {
    }

    void setOlist(String name,String cookname,int n,String time,String place){ //建立訂單
        try{
            order ord=new order(name,cookname,n,time,place); //生成具體訂單
            olist.add(ord);
        }catch(Exception e){
            System.out.print("查無此菜！\n");
            return;
        }
        finally{}
        System.out.print("已生成訂單，等待發貨\n");
    }

    void showOlist(){                   //顯示所有訂單
        Iterator it=olist.iterator();
        while(it.hasNext()){
            order o=(order)it.next();
            System.out.println(o.name+"\t"+o.cookname+"\t\t"+o.n+"\t"+o.time+"\t"+o.place+"\t"+o.nprice+"\t"+o.state);
        }
    }

    void setstate(int i){               //簽收第i個訂單
        order ord=(order)olist.get(i);
        ord.state="已簽收";
    }

    void dele(int i){               //刪除第i個訂單
        olist.remove(i);
    }
}

例項化前兩個類，並實現基本的增刪查改

import java.util.*;

/**
 * Created by zhangshuo on 2018/7/26.
 * 下單類主要是對訂單的一些動作
 *
 */
public class Orderdinner {
    Orderlist oderlist=new Orderlist();

    public void setorder(){    //建立訂單
        System.out.print("新建您的訂單，輸入您的名字、菜名、數量、時間、地點：");
        Scanner input=new Scanner(System.in);
        String name=input.next();
        String cookname=input.next();
        int n=input.nextInt();
        String time=input.next();
        String place=input.next();
        oderlist.setOlist(name,cookname,n,time,place);
    }

    public void showorder(){            //檢視訂單
        oderlist.showOlist();
    }

    public void orderok(){              //簽收訂單
        int i;
        Scanner input=new Scanner(System.in);
        System.out.print("輸入要簽收的序號：");
        i=input.nextInt();
        try {
            oderlist.setstate(i - 1);
        }catch(Exception e){
            System.out.print("訂單不存在！\n");
        }
        finally{}
    }

    public void dorporder(){            //刪除訂單
        int i;
        Scanner input=new Scanner(System.in);
        System.out.print("輸入要刪除的序號：");
        i=input.nextInt();
        try{
            oderlist.dele(i-1);
        }catch(Exception e){
            System.out.print("訂單不存在！\n");
        }
        finally{}
    }

    public void like(){                 //點贊
        String name;
        System.out.print("輸入您喜歡的菜名：");
        Scanner input=new Scanner(System.in);
        name=input.next();
        Cookbook.Cook c=(Cookbook.Cook)Cookbook.list.get((int)Cookbook.hsmap.get(name));//找到對應的行
        c.setLike();
        System.out.println("已點贊\n");
    }
}

顯示主要的樣式，呼叫動作類中的動作

void run(){
        Scanner input=new Scanner(System.in);
        Orderdinner buyfood=new Orderdinner();
        Cookbook cookbook=new Cookbook();
        boolean bb=true;
        while(bb){
            System.out.printf("1.檢視選單\n2.我要訂餐\n3.檢視餐袋\n4.簽收訂單\n5.刪除訂單\n6.我要點贊\n7.退出系統\n");
            int n=1;
            try{
                n=input.nextInt();
            }catch (Exception e){
                System.out.println("輸入選項不合法");
                return;
            }
            switch(n){
                case 1:
                    Cookbook.showall();
                    break;
                case 2:
                    buyfood.setorder();
                    break;
                case 3:
                    buyfood.showorder();
                    break;
                case 4:
                    buyfood.orderok();
                    break;
                case 5:
                    buyfood.dorporder();
                    break;
                case 6:
                    buyfood.like();
                    break;
                case 7:
                    System.out.println("退出系統");
                    bb=false;
                    break;
            }
        }
        input.close();
    }

    public static void main(String[] args) {
        Main m=new Main();
        m.run();
    }