NIO实现文件流插入数据（粘贴功能）

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package org1.NIO;import javafx.stage.Screen;import java.io.*;import java.nio.ByteBuffer;import java.nio.CharBuffer;import java.nio.MappedByteBuffer;import java.nio.channels.Channel;import java.nio.channels.FileChannel;import java.nio.charset.Charset;import java.util.Scanner;/** * Created by hadoop on 16-9-28.简单实现功能如下，不知道有没有不这么麻烦的方法 */public class PasteDemo {    public static void main(String[] args) {        String s ="text.txt";        int rows = 0;        int cols = 0;        Scanner input =new Scanner(System.in);        System.out.println("请分别输入行号，列号");        rows =input.nextInt();        cols =input.nextInt();        System.out.println("请输入插入的数据：");        insert(s,rows+1,cols+1,input.next());    }    private static void insert(String path, int rows, int cols,String data) {        File sourceFile =new File(path);        File distFile =new File("text2.txt");        FileChannel inChannel;        FileChannel outChannel;        try {            inChannel = new FileInputStream(sourceFile).getChannel();            MappedByteBuffer mbf =inChannel.map(FileChannel.MapMode.READ_ONLY,0,sourceFile.length());            CharBuffer  charBuffer = Charset.forName("utf-8").newDecoder().decode(mbf);            String []context=charBuffer.toString().split("\n");//主意这里的反斜杠！！！！！            System.out.println("测试分段的数据"+context[rows]);//一行            String insertLine=context[rows].substring(0,cols)+data+context[rows].substring(cols,context[rows].length());            System.out.println("测试修改的数据"+insertLine);            context[rows]=insertLine;            outChannel =new FileOutputStream(distFile).getChannel();            ByteBuffer byteBuffer =ByteBuffer.allocate(mbf.capacity()+data.length()*3);            int contextLen =context.length;            for (int i =0;i<contextLen;i++){                byteBuffer.put((context[i]+"\n").getBytes());//按行写入，加换行            }            //读取channel，需要置位            byteBuffer.flip();            outChannel.write(byteBuffer);            byteBuffer.clear();//写数据            System.out.println(byteBuffer);            System.out.println("position: "+byteBuffer.position()+" limit:"+byteBuffer.limit());        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }}
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