2月16日java周测整理

最新推荐文章于 2024-08-25 03:09:58 发布

BadManChd

最新推荐文章于 2024-08-25 03:09:58 发布

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本文链接：https://blog.youkuaiyun.com/weixin_43805212/article/details/87435535

本文深入探讨了Java编程的五个核心实践：控制台输出九九乘法表，实现两数相加，遍历并打印数组，抽象消费者购物场景，以及利用比较器对商品按价格排序。这些实例覆盖了基本语法、面向对象编程、数据结构操作和接口应用，是Java初学者和进阶者的实用教程。

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1.实现在控制台输出九九乘法表

package com.dodoke.test;

public class Test1 {
	public static void main(String[] args) {
		for (int i = 1; i <= 9; i++) {
			for (int j = 1; j <= i; j++) {
				System.out.print(i + "*" + j + "=" + i * j + "  ");
			}
			System.out.println();
		}
	}

}

2.定义方法sum，要求实现两个数之和的运算，要求在main方法中调用。

package com.dodoke.test;

public class Test2 {
	public void sum(int a,int b){
		int add = a+b;
		System.err.println(add);
	}
	public static void main(String[] args) {
		Test2 tt = new Test2();
		tt.sum(10, 2);	
		
	}
	

}

3.请写出一个方法打印数组内容，实现遍历数组，要求在main方法中调用。提示：在main方法中定义一个数组，然后讲数组作为参数传递给方法，在方法中打印结果"[a,b,c]";

package com.dodoke.test;

import java.util.Arrays;

public class Test3 {
	public static void main(String[] args) {
		
		//创建一个数组长度不为0 的数组
		String[] array = { "a", "b", "c" };
		//创建一个数组长度为0的数组
		String[] array2 = {};
		
		/**
		 * 调用工具类
		 */
		System.out.println(Arrays.toString(array));
		
		//打印数组
		System.out.println(Test3.fun(array));
		System.out.println(Test3.fun(array2));
	}
	public static String fun(String[] arr) {
		String result = "";
		if (arr.length == 0) {
			result = "数组长度为0";
		} else {
			//拼接"["
			result = result + "[";
			for (int i = 0; i < arr.length; i++) {
				if (i == arr.length - 1) {
					result += arr[i] + "]";
				} else {
					result += arr[i] + ", ";
				}
			}
		}
		return result;
	}
}

4.请将消费者在商城购物这个场景抽象出类，并编写一个客户端类，实现“小明在欧尚买了一件T恤”这个行为。
要求：要有接口，并使用内部类；

package Examination;
//抽象出人这个类
public class Person {
	private String name;

	public String getName() {
		return name;
	}

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

	public Person(String name) {
		super();
		this.name = name;
	}

package Examination;
//抽象出超市这个类
public class Supmak {
	
	private String name;

	public String getName() {
		return name;
	}

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

	public Supmak(String name) {
		super();
		this.name = name;
	}
	
	






}

package Examination;
//抽象出物品这个类
public class Product {
	private String name;

	public String getName() {
		return name;
	}

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

	public Product(String name) {
		super();
		this.name = name;
	}
	
	

}

package Examination;
public interface Buy {
	void bby(Person ren, Supmak ss, Product product);
	

}

package com.dodoke.test;

import Examination.Buy;
import Examination.Person;
import Examination.Product;
import Examination.Supmak;

public class Test5 {
	public static void main(String[] args) {
		Person chd = new Person("小明");
		Supmak ou = new Supmak("欧尚");
		Product po = new Product("T恤");
		Buy b = new Buy() {

			@Override
			public void bby(Person ren, Supmak ss, Product product) {
				System.out.println(ren.getName() + "在" + ss.getName() + "买了" + product.getName());

			}
		};
		b.bby(chd, ou, po);

	}

}

5.借助比较器，使用item具备按照价格从高到低排序：初始化10个item，并且Collections sort 进行排序，查看排序结果。

package Examination;

public class Item {
	private String name;
	private int  price;
	
	
	public Item() {
		super();
	}

	public Item(String name, int price) {
		super();
		this.name = name;
		this.price = price;
	}
	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;
	}

	@Override
	public String toString() {
		return "Item [name=" + name + ", price=" + price + "]";
	}
	
	
	

}

package com.dodoke.test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Random;

import Examination.Item;

public class Test4 {
public static void main(String[] args) {
	//创建集合
	List <Item> items = new ArrayList <Item> ();
	Random r = new Random();
	items.add(new Item("蓝瓶",100+r.nextInt(100)));
	items.add(new Item("血瓶",100+r.nextInt(100)));
	items.add(new Item("药水",100+r.nextInt(100)));
	items.add(new Item("蓝药水",100+r.nextInt(100)));
	items.add(new Item("红药水",100+r.nextInt(100)));
	items.add(new Item("分药水",100+r.nextInt(100)));
	items.add(new Item("紫药水",100+r.nextInt(100)));
	items.add(new Item("黄药水",100+r.nextInt(100)));
	items.add(new Item("绿药水",100+r.nextInt(100)));
	items.add(new Item("黑药水",100+r.nextInt(100)));
	
	Comparator <Item> ac = new Comparator <Item> (){

		@Override
		public int compare(Item o1, Item o2) {
			if(o1.getPrice()<o2.getPrice()){
				return 1;
			}else{
			return -1;
			}
		}

		
		
	};
	Collections.sort(items,ac);
	System.out.println(items);
	
	}
}