Java文件操作

import java.io.*;
import java.nio.channels.FileChannel;

public class IOTest {

    public static void main(String[] args) throws IOException {
        //读取文件
        String filePath = "C:/Users/Administrator/Desktop/";
        String fileName = "test.txt";
        String fileName2 = "copytest.txt";
        File f = new File(filePath+fileName);
        File f2 = new File(filePath+fileName2);
        BufferedReader bfr = new BufferedReader(new FileReader(f));
        String str = null;
        while((str = bfr.readLine()) != null){
            System.out.println(str);
        }

        //写入文件
        //判断文件是否存在
        if(f.exists()){
            FileOutputStream fos = new FileOutputStream(f);
            String s = "123456";
            byte[] b = s.getBytes();
            fos.write(b);
            fos.close();
        } else {
            System.err.println("文件不存在!");
        }

/*      //复制文件
        //文件输入流
        FileInputStream fis = new FileInputStream(f);
        FileOutputStream fos = new FileOutputStream(f2);
        int buffer;
        while((bufferi=fis.read())>0){
            fos.write(buffer);
        }*/

        //复制文件(文件通道)
        /*FileInputStream fin = new FileInputStream(f);
        FileOutputStream fout = new FileOutputStream(f2);
        FileChannel in = fin.getChannel();
        FileChannel out = fout.getChannel();
        in.transferTo(0, in.size(), out);
        */
        //文件复制（字符流）
        FileReader fr = new FileReader(f);
        FileWriter fw = new FileWriter(f2);
        char[] c =new char[1024];
        fr.read(c);
        fw.write(c);
        fw.flush();
        fw.close();

        //文件分割
        int num = 5;//分割数量
        int len =(int) f.length()/num;//单个文件长度
        System.out.println(f.length());
        if((int) f.length()%num!=0){//如果文件长度不能被数量整除则+1
            num++;
        }
        fr.read(c);///读入文件数据到数组
        for(int i=0;i<num;i++){//循环创建文件
            FileWriter fout = new FileWriter(filePath+"cut"+i+".txt");
            fout.write(c, len*i, len);//写入到新文件
            fout.flush();
        }
        //文件合并
        char[] ch = new char[1024];//缓冲数组
        int length = 0;
        for(int i=0;i<num;i++){
            File ff =new File(filePath+"cut"+i+".txt");
            FileReader fin =new FileReader(ff);
            fin.read(ch, length, (int) ff.length());
            length += (int)ff.length();
        }
        FileWriter fww = new FileWriter(filePath + "sum.txt");
        fww.write(ch);
        fww.flush();

        //移动文件
        /*File mov =new File(filePath+"xx.txt");
        mov.renameTo(new File("C:\Files\"+mov.getName()));*/
    }   

}