动手动脑（六）

编写一个程序，指定一个文件夹，能自动计算出其总容量:import java.io.File;

import java.util.ArrayList;

public class FileAction {
    ArrayList<File> fileList;
    File root;

    public FileAction(String pathName) {
        root = new File(pathName);
        fileList = new ArrayList<>();
    }

    public void searchFiles() {
        File[] files = root.listFiles();
        int length = files.length;
        for (int i = 0; i < length; i++) {
            if (files[i].isDirectory()) {
                root = files[i];
                searchFiles();
            } else {
                fileList.add(files[i]);
            }
        }
    }

    public void countFiles() {
        long totalSize = 0;
        System.out.println("文件数:" + fileList.size());
        for (int i = 0; i < fileList.size(); i++) {
            totalSize += fileList.get(i).length();
        }
        System.out.println("文件总大小:" + totalSize);
    }

    public static void main(String[] args) {
        String pathName = "E:\音乐";
        FileAction counter = new FileAction(pathName);
        counter.searchFiles();
        counter.countFiles();
    }

}

编写一个文件加解密程序，通过命令行完成加解密工作:

import java.io.*;
public class FileCode 
{
 private static final int numOfEncAndDec=0x99;//加密解密密钥
 private static int dataOfFile=0;//文件字节内容

 public static void main(String[] args) 
{
  File srcFile=new File("E:\新建文件夹\poem.txt");//初始化文件
  File encFile=new File("E:\新建文件夹\poem1.txt"); //加密文件
  File decFile=new File("E:\新建文件夹\poem2.txt");  //解密文件
  
  try {
   //EncFile(srcFile,encFile);  //加密操作
   //DecFile(encFile,decFile);//解密操作
    
      EncFile(srcFile,decFile);  //加密操作

 


      DecFile(decFile,encFile);
  }catch(Exception e) {
   e.printStackTrace();
  }
 }
 private static void EncFile(File srcFile,File encFile)throws Exception{
  if(!srcFile.exists()) {
   System.out.println("source file not exixt");
   }
  if(!encFile.exists()) {
   System.out.println("encrypt file created");
   encFile.createNewFile();//若无加密文件，新建一个加密文件
  }
  InputStream fis=new FileInputStream(srcFile);
  OutputStream fos=new FileOutputStream(encFile);
  
  while((dataOfFile=fis.read())>-1) {//当读到文件内容时
   fos.write(dataOfFile^numOfEncAndDec);//将读出的内容加密后写入
  }
  fis.close();
  fos.flush();
  fos.close();
 }
 private static void DecFile(File encFile,File decFile)throws Exception{
  if(!encFile.exists()) {
   System.out.println("encrypt file not exixt");
  }
  if(!decFile.exists()) {
   System.out.println("decrypt file created");
   decFile.createNewFile();
  }
  InputStream fis=new FileInputStream(encFile);
  OutputStream fos=new FileOutputStream(decFile);
  
  while((dataOfFile=fis.read())>-1) {
   fos.write(dataOfFile^numOfEncAndDec);
  }
  fis.close();
  fos.flush();
  fos.close();
 }

}

编写一个文件分割工具，能把一个大文件分割成多个小的文件。并且能再次把它们合并起来得到完整的文件

package filesoperation;

import java.io.*;import java.nio.*;import java.util.ArrayList;
public class CutFile extends SimpleFileVisitor<Path>
{
    public static ArrayList<Path> smallfiles = new ArrayList<>();
    public static void main(String[] args) {
        cut("E:\test.txt", "E:\test", 1024 * 1024 * 1);
        paste("E:\test", "E:\test1", 1024 * 1024 * 1);
    }
    public static void cut(String filepath, String endpath, int sizeofsmallfile) {   //原文件，切割后小文件路径，小文件最大容量
        FileInputStream fis = null;
        File file = null;
        try {
            fis = new FileInputStream(filepath);
            file = new File(filepath);
            byte[] b = new byte[sizeofsmallfile];
            int read = 0;
            int numberofsmallfile = 1;
            while ((read = fis.read(b)) != -1) {
                String nameoflargefile = file.getName();    //获取大文件全名(带扩展名)
                String nameofsmallfile = nameoflargefile.substring(0, nameoflargefile.lastIndexOf("."));   //获取小文件名(不带扩展名)
                String extension = nameoflargefile.substring(nameoflargefile.lastIndexOf("."), nameoflargefile.length());  //获取扩展名
                FileOutputStream fos = new FileOutputStream(endpath + "\" + nameofsmallfile + "-" + numberofsmallfile + extension); //创建小文件
                fos.write(b, 0, read);    //写入
                fos.close();
                numberofsmallfile++;
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    public static void paste(String smallfilespath, String endpath, int sizeofsmallfile) {      //小文件路径，生成的大文件路径，小文件最大容量
        Path fileDirPath = Paths.get(smallfilespath);
        CutFile visitor = new CutFile();
        try {
            Files.walkFileTree(fileDirPath, visitor);
            File file = new File(smallfiles.get(0).toString());
            String nameofsmallfile = file.getName();    //获取第一个小文件全名(带扩展名)
            String nameoflargefile = nameofsmallfile.substring(0, nameofsmallfile.lastIndexOf("-"));    //获取大文件名(不带扩展名)
            String extension = nameofsmallfile.substring(nameofsmallfile.lastIndexOf("."), nameofsmallfile.length());   //获取扩展名
            FileOutputStream fos = new FileOutputStream(endpath + "\" + nameoflargefile + extension);    //创建大文件
            byte[] b = new byte[sizeofsmallfile];
            for(Path p:smallfiles) {
                FileInputStream fis = new FileInputStream(p.toString());
                int read = fis.read(b);
                fis.close();
                fos.write(b, 0, read);    //写入
            }
            fos.close();
        }catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
        if(attrs.isRegularFile()){
            smallfiles.add(file);
        }
        return FileVisitResult.CONTINUE;
    }
}