1.任务要求：
在DOS窗口下，实现查看全文、统计总行数/总页码数、查找指定行、指定页码、翻页
2.阅读器实现方式
输入1(查看全文、统计总行数/总页码数、)
输入2（读取指定行，查找其上下行）
输入+显示下一行，输入-显示上一行，输入bye返回上一级
输入3（查找指定页码，实现翻页功能）
输入+显示下一页，输入-显示上一页，输入bye返回上一级
3.具体代码如下
主要分为三个子程序，然后在主程序中分别进行调用，以此来实现小说阅读器的各功能。
import java.io.*;
import java.util.Scanner;
class Display_txt
{
//查看全文（以每10个段落为一页，统计总行数）
static void ReadAll (String fileName) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));//使用缓冲区的方法将数据读入到缓冲区中
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) //分页(以每10个段落为一页)
{
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+"页\n");
}
//查看指定页码，实现上下翻页
static void getPage (String fileName) throws IOException
{
System.out.println("(提示：输入00返回上一级)");
System.out.print("请输入查询页码：");
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：输入+(下一页)；输入-(上一页);输入bye(返回上一级);");
System.out.print("请输入：");
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("请输入：");
pageNumber1=sc1.next();
}
}
line=br.readLine();
}
System.out.println("(提示：输入00返回上一级)");
System.out.print("请输入查询页码：");
pageNumber=sc.nextInt();
}
System.out.println("返回到上一级");
}
//读取指定行,并查看上下行
static void readxxLine (String fileName) throws IOException
{
System.out.println("(提示：输入00返回上一级)");
System.out.print("请输入查询行：");
Scanner sc=new Scanner(System.in);
int lineNumber=sc.nextInt();
while(lineNumber!=00)
{
BufferedReader br = new BufferedReader(new InputStreamReader (new FileInputStream (fileName)));//使用缓冲区的方法将数据读入到缓冲区中
String line = br.readLine();
int num=0;
while(line!= null)
{
if(lineNumber==++num)
{
System.out.println("["+lineNumber+"]:"+line);
System.out.println("提示：输入+(下一行)；输入-(上一行)；输入bye(返回上一级)");
System.out.print("请输入：");
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：输入00返回上一级)");
System.out.print("请输入查询行：");
lineNumber=sc.nextInt();
}
System.out.println("返回上一级");
}
//主程序
public static void main(String[] args) throws IOException
{
String fileName ="E:/java task/cookie reader/哲学家都干了些什么.txt";
System.out.println("提示：输入1(查看全文,统计全文总行数和总页码数)；输入2(读取指定行，并查看上下行)；输入3(查看指定页码的内容，上下翻页)；");
while(true)
{
System.out.print("请输入：");
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("输入错误");
}
System.out.println("提示：输入1(查看全文,统计全文总行数和总页码数)；输入2(读取指定行，并查看上下行)；输入3(查看指定页码的内容，上下翻页)；");
}
}
}