Java学习——泛型与容器类、初步项目创建

• 1.学习内容
• • 2.学习方式

1.学习内容

了解了泛型的概念，掌握如何使用泛型，泛型是将数据类型参数化，使一个类或一个方法可以在多种不同的类型对象中操作。

package Classwork;

public class Fanxin01<T> {
    private T all;
    public T all(){
        return all;
    }

    public T getAll() {
        return all;
    }

    public void setAll(T all) {
        this.all = all;
    }

    public static void main(String[] args) {
        Fanxin01<String> a=new Fanxin01<String>();
        Fanxin01<Integer> b=new Fanxin01<Integer>();
        a.setAll("ty");
        System.out.println(a.getAll());
        b.setAll(18);
        System.out.println(b.getAll());
        a.setAll("169cm");
        System.out.println(a.getAll());
        a.setAll("2003.04.29");
        System.out.println(a.getAll());
        a.setAll("打打游戏，听听音乐，出去玩");
        System.out.println("爱好："+a.getAll());
    }
}

了解容器类，掌握容器接口Collection、列表接口List、集合接口Set。

package Classwork;
import java.util.*;
class Stringstack{
    private LinkedList<String> ld=new LinkedList<String>();
    //private 使ld对象仅在Stringstack类中使用
    public void push(String name){
        ld.addFirst(name);
    }
    public String pop(){
        return ld.removeFirst();
    }
    public boolean isEmpty(){
        return ld.isEmpty();
    }

}

public class LinkedList01 {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        Stringstack stack=new Stringstack();
        System.out.println("请输入数据(stop 结束)");
        while (true){
            String intput=sc.next();
            if(intput.equals("stop"))
                break;
            stack.push(intput);
        }
        System.out.println("先进后出的顺序：");
        while (!stack.isEmpty())
            System.out.println(stack.pop());
    }

}

做了关于小吃店的项目，还未完善！！！

package Snackbarsystem;

import java.util.Scanner;

public class loginFood extends managerFood {
    public static void main(String[] args) throws Exception {
        System.out.println("请输入您的身份：");
        for (int i = 0; i < 3; i++) {
            System.out.println();
        }
        System.out.println("1.管理员       2.用户");
        Scanner x = new Scanner(System.in);
        int identity = x.nextInt();
        if (identity == 1) {
            managerFood m = new managerFood();
            m.show();
        }
        if (identity == 2) {
            userFood u = new userFood();
            u.user();
        }
    }
}

package Snackbarsystem;

public class Food {
    private int id;
    private String name;
    private int price;
    private String taste;
    public Food(){
    }

    @Override
    public String toString() {
        return
                "    "+id+"\t    "+name+"\t    "+price+"\t    "+taste+"\t         \n";
    }

    public Food(int id, String name, int price, String taste){
            this.id=ida;
            this.name=name;
            this.price=price;
            this.taste=taste;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public int getPrice() {
        return price;
    }

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

    public String getTaste() {
        return taste;
    }

    public void setTaste(String taste) {
        this.taste = taste;
    }
}

package Snackbarsystem;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;

public class managerFood {
    public  void  show()throws Exception {
        ArrayList<Food> f = new ArrayList<Food>();
        Food f1 = new Food(01, "榴莲酥", 5, "咸甜");
        Food f2 = new Food(02, "西瓜捞", 8, "凉甜");
        Food f3 = new Food(03, "蛋焗南瓜", 10, "鲜甜");
        f.add(f1);
        f.add(f2);
        f.add(f3);
        while (true)//无限循环
        {
            System.out.println("----小吃店管理系统----");
            System.out.println("1.添加小吃");
            System.out.println("2.删除小吃");
            System.out.println("3.更改小吃");
            System.out.println("4.查看小吃");
            System.out.println("5.退出");
            System.out.println("请选择系统功能：");
            Scanner sc = new Scanner(System.in);
            int n = sc.nextInt();
            if (n == 1) {
                addFood(f);
            } else if (n == 2) {
                deleteFood(f);
            } else if (n == 3) {
                changeFood(f);
            } else if (n == 4) {
                checkFood(f);
            } else if (n == 5) {
                System.out.println("谢谢使用小京系统");
                break;
            }
        }
    }
    public static void addFood(ArrayList<Food> f)throws Exception{
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入小吃编号：");
        int id=sc.nextInt();
        boolean flag=true;
        for (int i=0;i<f.size();i++){
            Food a=f.get(i);//遍历数组列表
            if (a.getId()==id){
                flag=false;
                System.out.println("该小吃已存在");
                break;
            }
        }
        if (flag){
            System.out.println("请输入小吃名字：");
            String Name=sc.next();
            System.out.println("请输入小吃价格");
            int Price=sc.nextInt();
            System.out.println("请输入小吃口味");
            String Taste=sc.next();
            Food fo=new Food();
            fo.setId(id);
            fo.setName(Name);
            fo.setPrice(Price);
            fo.setTaste(Taste);
            f.add(fo);
            try(
               BufferedWriter in=new BufferedWriter(new FileWriter("D:\\idea java\\Foodmagaer\\food1.txt",true));
                    ){
                PrintWriter fw=new PrintWriter(in);
                fw.print(fo);
                fw.flush();
            }
            System.out.println("添加成功！");
        }
    }
    public static void deleteFood(ArrayList<Food> f)throws Exception{
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入要删除的小吃编号");
        int num=sc.nextInt();
        int all=-1;//创建索引，找数组列表中以有数据
        for (int i=0;i<f.size();i++){
            Food food=f.get(i);//遍历数组列表
            if (food.getId()==num) //判断改小吃是否存在
            {
                all=i;
                break;
            }
        }
            if(all==-1){
                System.out.println("无此小吃，请重新选择");
            }
            else {
                f.remove(all);
                System.out.println("删除小吃成功");
            }
    }
        public static void changeFood(ArrayList<Food> f)throws Exception{
        Scanner sc=new Scanner(System.in);
            System.out.println("请输入你要修改的小吃编号");
            int id=sc.nextInt();
            int all=-1;//创建索引，找数组列表中以有数据
            for (int i=0;i<f.size();i++){
                Food fo=f.get(i);
                if (fo.getId()==id)//判断改小吃是否存在
                {
                    all=1;
                    break;
                }
            }
            if (all==-1){
                System.out.println("您要改变的小吃不存在");
            }
            else{
                System.out.println("请输入新小吃名字：");
                String Name=sc.next();
                System.out.println("请输入新小吃价格");
                int Price=sc.nextInt();
                System.out.println("请输入新小吃口味");
                String Taste=sc.next();
                Food fo=new Food();
                fo.setId(id);
                fo.setName(Name);
                fo.setPrice(Price);
                fo.setTaste(Taste);
                f.set(id-1,fo);//将已完善的小吃在数组列表中创建
                System.out.println("修改小吃信息成功");
            }
        }
        public static void checkFood(ArrayList<Food> f){
        if (f.size()==0){
            System.out.println("暂无小吃信息");
            return;//停止程序运行下去
        }
            System.out.println("编号:\t小吃名:\t   价格:\t    口味:");
                 //  \t将光标移入下一行
            for (int i=0;i<f.size();i++){
                Food food=f.get(i);
                System.out.println("    "+food.getId()+"\t    "+food.getName()+"\t    "+food.getPrice()+"\t    "+food.getTaste()+"\t         ");
            }
        }
}

package Snackbarsystem;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.Scanner;

public class userFood {
    public void user() throws Exception {
        while (true) {
            System.out.println("----小吃店用户系统----");
            System.out.println("1.查看小吃");
            System.out.println("2.查看订餐电话");
            System.out.println("3.查看本店介绍");
            System.out.println("4.退出");
            Scanner ch = new Scanner(System.in);
            int choose = ch.nextInt();
            if (choose == 1) {
                System.out.println("----欢迎查看小吃----");
                try (
                        BufferedReader out =new BufferedReader (new FileReader("D:\\idea java\\Foodmagaer\\food1.txt"));
                ) {
                    String check;
                    while ((check = out.readLine()) != null) {
                        System.out.println(check);
                    }

                }
            }
            if (choose == 2) {
                System.out.println("订餐热线：100820-820-110");
            }
            if (choose == 3) {
                try (
                        BufferedReader bf = new BufferedReader(new FileReader("D:\\idea java\\Foodmagaer\\src\\File\\Food.txt"));
                ) {
                    String introduce;
                    while ((introduce = bf.readLine()) != null)
                    {
                        System.out.println(introduce);
                    }
                }
            }
            if (choose == 4) {
                System.out.println("感谢使用小京系统");
                break;
            }
        }
    }
}

2.学习方式

主要将精力放在练习中，在实践中检验自己学过的知识。