hashtabledemo.java

本java源程序包括了大量的学习程序（共27章）方便大家学习

import java.util.*;
public class HashtableDemo 
{
	public static void main(String[] args) 
	{
		Hashtable hashtable = new Hashtable();
		//声明并初始化Hashtable的对象hashtable
		float price[] = {3.00f,2.00f,1.50f,1.00f,0.50f,0.25f};
		//声明并初始化float型数组
		//以下是利用Hashtable的put()方法，将float数组元素对应键值加入到Hashtable中
		hashtable.put("mint",String.valueOf(price[0]));
		hashtable.put("near mint",String.valueOf(price[1]));
		hashtable.put("very fine",String.valueOf(price[2]));
		hashtable.put("fine",String.valueOf(price[3]));
		hashtable.put("good",String.valueOf(price[4]));
		hashtable.put("poor",String.valueOf(price[5]));
		Book book[] = new Book[3];  //声明并创建Book类的对象数组
		book[0] = new Book("Java","1A","very fine",54.00f);
		//初始化对象数组
		float f1=Float.parseFloat((String)hashtable.get(book[0].condition));
		//利用Hashtable的get()方法提取出对应键值为book[i].condition内容，
		//并先转型为String型，再由String型数据转换成float型数据
		book[0].setPrice(f1);
		//利用Book类中的setPrice()方法设定price属性
		book[1] = new Book("c++","1A","fine",42.00f);
		//初始化对象数组
		float f2=Float.parseFloat((String)hashtable.get(book[1].condition));
		book[1].setPrice(f2);
		//利用Book类中的setPrice()方法设定price属性
		book[2] = new Book("Delphi","2B","good",26.00f);
		//初始化对象数组
		float f3=Float.parseFloat((String)hashtable.get(book[1].condition));
		book[2].setPrice(f2);
		//利用Book类中的setPrice()方法设定price属性
		for(int i=0;i<book.length;i++)
		{
			System.out.println("Title:"+book[i].title);
			System.out.println("BookNumber:"+book[i].bookNumber);
			System.out.println("Condition:"+book[i].condition);
			System.out.println("Price:"+book[i].price+"\n");
		}
	}
}
class Book
{
	String title;
	String bookNumber;
	String condition;
	float basePrice;
	float price;
	Book(String title,String bookNumber,String condition,float basePrice)
	{
		this.title = title;
		this.bookNumber = bookNumber;
		this.condition = condition;
		this.basePrice = basePrice;
	}
	public void setPrice(float f)
	{
		price = basePrice*f;
	}
}