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  • 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");
            }
    }

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  • 原文地址:https://www.cnblogs.com/123-haozijia/p/11800790.html
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