1.任務要求：

在DOS視窗下，實現檢視全文、統計總行數/總頁碼數、查詢指定行、指定頁碼、翻頁

2.閱讀器實現方式

輸入1(檢視全文、統計總行數/總頁碼數、)

輸入2（讀取指定行，查詢其上下行）

輸入+顯示下一行，輸入-顯示上一行，輸入bye返回上一級

輸入3（查詢指定頁碼，實現翻頁功能）

輸入+顯示下一頁，輸入-顯示上一頁，輸入bye返回上一級

3.具體程式碼如下

主要分為三個子程式，然後在主程式中分別進行呼叫，以此來實現小說閱讀器的各功能。

import java.io.*;
import java.util.Scanner;
 

class Display_txt 
{
	//檢視全文（以每10個段落為一頁，統計總行數）
	static void ReadAll (String fileName) throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));//使用緩衝區的方法將資料讀入到緩衝區中
		String str;
		int i=1;
		int a=0,b=1;
		while((str = br.readLine()) != null)
		{
 

			System.out.println( "["+i+"]:" + str);
			System.out.println( );
			if(i==a+10)   //分頁(以每10個段落為一頁)
			{
				System.out.println("------------------------  page "+b+"  ------------------------");
				a=a+10;
				b=b+1;
			}
			i=i+1;
		}
		System.out.println("------------------------  page "+b+"  ------------------------\n"
 
);
		i=i-1;
		System.out.println("本文共有"+i +"行;   共有"+b+"頁\n");
	}
 
	//檢視指定頁碼，實現上下翻頁
	static void getPage (String fileName) throws IOException
	{
		System.out.println("(提示：輸入00返回上一級)");
		System.out.print("請輸入查詢頁碼：");
		Scanner sc=new Scanner(System.in);
		int pageNumber=sc.nextInt();	
		while(pageNumber!=00)
		{		
			BufferedReader br = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));			
			String line = br.readLine();		
			int num=0;	
			int startNumber=(pageNumber-1)*10+1;
			int endNumber=pageNumber*10;
			while(line!= null)
			{		
				if(startNumber==++num)  
				{	
					
					System.out.println("["+startNumber+"]:"+line);
					int i=startNumber;
					while(i<endNumber)
					{
						i=i+1;
						line=br.readLine();
						System.out.println("["+i+"]:"+line);	
					}
					System.out.println("-------------------page "+ pageNumber+"--------------------");
					System.out.println("(提示：輸入+(下一頁)；輸入-(上一頁);輸入bye(返回上一級);");
					System.out.print("請輸入：");					
					Scanner sc1=new Scanner(System.in);
					String pageNumber1=sc1.next();
					int pn=pageNumber;
					while(!pageNumber1.equals("bye"))
					{					
						if(pageNumber1.equals("+"))
						{	
							BufferedReader br1 = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));
							String line1=br1.readLine();
							pn=pn+1;
							int num1=0;
							int startNumber1=(pn-1)*10+1,endNumber1=pn*10;
							while(line1!= null)
							{
								if (startNumber1==++num1)
								{
									System.out.println("["+startNumber1+"]:"+line1);
									int a=startNumber1;
									while(a<endNumber1)
									{
										a=a+1;
										line1=br1.readLine();
										System.out.println("["+a+"]:"+line1);
									}
									System.out.println("-------------------page "+ pn+"--------------------");

								}
								line1=br1.readLine();
							}
						}
						if(pageNumber1.equals("-"))
						{	
							BufferedReader br2 = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));
							String line2=br2.readLine();
							pn=pn-1;
							int num2=0;
							int startNumber2=(pn-1)*10+1,endNumber2=pn*10;
							while(line2!= null)
							{
								if (startNumber2==++num2)
								{
									System.out.println("["+startNumber2+"]:"+line2);
									int b=startNumber2;
									while(b<endNumber2)
									{
										b=b+1;
										line2=br2.readLine();
										System.out.println("["+b+"]:"+line2);
									}
									System.out.println("-------------------page "+ pn+"--------------------");

								}
								line2=br2.readLine();
							}
						}
						else
						{}
						System.out.print("請輸入：");
						pageNumber1=sc1.next();	
					}
				}
				line=br.readLine();	
			}
			System.out.println("(提示：輸入00返回上一級)");
			System.out.print("請輸入查詢頁碼：");
			pageNumber=sc.nextInt();
		}
		System.out.println("返回到上一級");	
	}
		//讀取指定行,並檢視上下行
	static void readxxLine (String fileName) throws IOException
	{
		System.out.println("(提示：輸入00返回上一級)");
		System.out.print("請輸入查詢行：");
		Scanner sc=new Scanner(System.in);
		int lineNumber=sc.nextInt();	
		while(lineNumber!=00)
		{		
			BufferedReader br = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));//使用緩衝區的方法將資料讀入到緩衝區中			
			String line = br.readLine();		
			int num=0;	
			while(line!= null)
			{	
				if(lineNumber==++num)  
				{	
					System.out.println("["+lineNumber+"]:"+line);
					System.out.println("提示：輸入+(下一行)；輸入-(上一行)；輸入bye(返回上一級)");
					System.out.print("請輸入：");
					Scanner sc1=new Scanner(System.in);
					String lineNumber1=sc1.next();
					int ln=lineNumber;
					while(!lineNumber1.equals("bye"))
					{					
						if(lineNumber1.equals("+"))
						{	
							BufferedReader br1 = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));
							String line1=br1.readLine();
							ln=ln+1;
							int num1=0;
							while(line1!= null)
							{
								if (ln==++num1)
								{
									System.out.println("["+ln+"]:"+line1);
								}
								line1=br1.readLine();
							}
						}
						if(lineNumber1.equals("-"))
						{	
							BufferedReader br2 = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));
							String line2=br2.readLine();
							ln=ln-1;
							int num2=0;
							while(line2!= null)
							{
								if (ln==++num2)
								{
									System.out.println("["+ln+"]:"+line2);
								}
								line2=br2.readLine();
							}
						}
						else
						{}
						lineNumber1=sc1.next();					
					}
				}
				line=br.readLine();	
			}
			System.out.println("(提示：輸入00返回上一級)");
			System.out.print("請輸入查詢行：");
			lineNumber=sc.nextInt();
		}
		System.out.println("返回上一級");	
	}
	//主程式
	public static void main(String[] args) throws IOException
	{
		String fileName ="E:/java task/cookie reader/哲學家都幹了些什麼.txt";
		System.out.println("提示：輸入1(檢視全文,統計全文總行數和總頁碼數)；輸入2(讀取指定行，並檢視上下行)；輸入3(檢視指定頁碼的內容，上下翻頁)；");
		while(true)
		{
			
			System.out.print("請輸入：");
			Scanner sc=new Scanner(System.in);
			int j=sc.nextInt();			
			if(j==1)
			{	
				ReadAll(fileName);
				j=0;
			}
			if(j==2)
			{	
				readxxLine(fileName);
				j=0;
			}
			if(j==3)
			{	
				getPage(fileName);
				j=0;
			}
			if(j==0)
			{}
			else
			{	
				System.out.println("輸入錯誤");
			}
			System.out.println("提示：輸入1(檢視全文,統計全文總行數和總頁碼數)；輸入2(讀取指定行，並檢視上下行)；輸入3(檢視指定頁碼的內容，上下翻頁)；");
		}
	}
}