课后作业

编写一个程序，指定一个文件夹，能自动计算出其总容量

package Chengji;

import java.io.File;
import java.util.ArrayList;
public class Rongliang {
    static long rl=0;
    private static ArrayList<String> filelength=new ArrayList<String>();
    public void getFiles(String filePath)
    {
        File root=new File(filePath);
        File[] files=root.listFiles();
        for(File file:files)
        {
            if(file.isDirectory())
            {
                getFiles(file.getAbsolutePath());
                filelength.add(file.getAbsolutePath());
            }
            else
            {
                rl+=file.getAbsolutePath().length();
            }
        }
        System.out.println("大小为："+rl);
    }
    public static void main(String[] args)
    {
        Rongliang s=new Rongliang();
        String filePath="C:\Users\北方\Desktop\1-信1807-5 郝子嘉 20183684";
        s.getFiles(filePath);
    }

}

 编写一个文件加解密程序，通过命令行完成加解密工作；

package Chengji;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
public class Secret {
    private static final int n=0x99;
     private static int dt=0;

     public static void main(String[] args) {
      File srcFile=new File("a.txt");
      File encFile=new File("b.txt");
      File decFile=new File("c.txt"); 
     
      try {
       EncFile(srcFile,encFile); 
       DecFile(encFile,decFile);
      }catch(Exception e) {
       e.printStackTrace();
      }
     }
     private static void EncFile(File srcFile,File encFile)throws Exception{
      if(!srcFile.exists()) {
       System.out.println("不存在");
       }
      if(!encFile.exists()) {
       System.out.println("已被创建");
       encFile.createNewFile();
      }
      InputStream is=new FileInputStream(srcFile);
      OutputStream os=new FileOutputStream(encFile);
     
      while((dt=is.read())>-1) {//当读到文件内容时
       os.write(dt^n);//将读出的内容加密后写入
      }
      is.close();
      os.flush();
      os.close();
     }
     private static void DecFile(File encFile,File decFile)throws Exception{
      if(!encFile.exists()) {
       System.out.println("不存在");
      }
      if(!decFile.exists()) {
       System.out.println("已被创建");
       decFile.createNewFile();
      }
      InputStream fis=new FileInputStream(encFile);
      OutputStream fos=new FileOutputStream(decFile);
     
      while((dt=fis.read())>-1) {
       fos.write(dt^n);
      }
      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 Chengji;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class Fenge {
    private static void cutFile(String src, String endsrc, int num) {
        FileInputStream fis = null;
        File f = null;
        try {
            fis = new FileInputStream(src);
            f = new File(src);
            byte[] b = new byte[num];
            int len = 0;
            int name1 = 1;
            while ((len = fis.read(b)) != -1) {
                String name2 = f.getName();
                int lastIndexOf = name2.lastIndexOf(".");
                String substring = name2.substring(0, lastIndexOf);
                String substring2 = name2.substring(lastIndexOf, name2.length());
                FileOutputStream fos = new FileOutputStream(endsrc + "\\"+ substring + "-" + name1 + substring2);
                fos.write(b, 0, len);
                fos.close();
                name1++;
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    private static void togetherFile(String src, String endsrc){
        FileOutputStream fos = null;
        File file1 = null;
        File file2 = null;
        try {
            file1 = new File(endsrc);
            file2 = new File(src);
            fos = new FileOutputStream(endsrc);
            for(File file : file2.listFiles()){

                FileInputStream fis = new FileInputStream(file.getAbsolutePath());

                byte[] b = new byte[1024*1024];
                int len = 0;
                while((len = fis.read(b)) != -1){
                    fos.write(b, 0, len);
                }
                fis.close();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                if(fos != null){
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
        public static void main(String[] args){
            cutFile("C:\Users\北方\Desktop\1-信1807-5 郝子嘉 20183684\HPATSS\Harry Potter and the Sorcerer's Stone.txt", "C:\Users\北方\Desktop\1-信1807-5 郝子嘉 20183684\HPATSS",10 * 10 * 20);          
            togetherFile("C:\Users\北方\Desktop\1-信1807-5 郝子嘉 20183684\HPATSS","C:\Users\北方\Desktop\1-信1807-5 郝子嘉 20183684\HPATSS\Harry Potter and the Sorcerer's Stone.txt");
        }
}