2020.8.8第三十三天

1.今天复习第十二章

工具类

import java.io.*;
  public class IOUtils {
   public static void main(byte[] ary) {
          //byte[] ary={41,4,-2,(byte)0xfe,(byte)0xff};
          for(int b:ary) {
              b&=0xff;
               if(b<=0xf)
                  System.out.print("0");
              System.out.print(Integer.toHexString(b)+" ");
          }
          System.out.println();
      }
      public static byte[] read(String file) {
         try {
              InputStream  in=new FileInputStream(file);
             byte[] buf=new byte[in.available()];
             in.read(buf);
             in.close();
             return buf;
             e.printStackTrace();
             throw new RuntimeException(e);
       }
    }
    public static Object deepCopy(Object obj) {
       try {
            ByteArrayOutputStream buf=new ByteArrayOutputStream();
             ObjectOutputStream oos=new ObjectOutputStream(buf);
           oos.writeObject(obj);
           oos.close();
          byte[] ary=buf.toByteArray();
            ObjectInputStream ois=new ObjectInputStream(new ByteArrayInputStream(ary));
            Object o=ois.readObject();
              ois.close();
            return o;
        }catch(Exception e) {
             throw new RuntimeException(e);
         }
    }
      public static void cp(File from,File to) {
          try {
            InputStream in=new FileInputStream(from);
            OutputStream out=new FileOutputStream(to);
           byte[] buf=new byte[1024];
              int n;
            while((n=in.read(buf))!=-1) {
                //System.out.println("n:"+n);
               out.write(buf,0,n);
             }
            in.close();
            out.close();
         }catch(IOException e) {
             e.printStackTrace();
            throw new RuntimeException(e);
         }
     }
      public static void cpl(File from,File to) {
        try {
             InputStream in=new FileInputStream(from);
              OutputStream out=new FileOutputStream(to);
           int b;
            while((b=in.read())!=-1) {
                out.write(b);
            }
            in.close();
         }catch(IOException e) {
            e.printStackTrace();
             throw new RuntimeException(e);
        }
    }
    public static void cp(String from,String to) {
        cp(new File(from),new File(to));
    }
     public static void print(File file) {
       try {
            InputStream in=new FileInputStream(file);
            int b;
            int i=1;
              while((b=in.read())!=-1) {
                if(b<=0xf)
                     System.out.print("0");
                System.out.print(Integer.toHexString(b)+" ");
                 if(i++ % 16==0) {
                    System.out.println();
                }
             }
             System.out.println();
            in.close();
        }catch(IOException e) {
          e.printStackTrace();
             throw new RuntimeException(e);
        }
    }
    public static void print(String file) {
        print(new File(file));
   }
    public static void split(String file,int size) {
       try {
            if(size<=0) {
                throw new IllegalArgumentException("搞啥呀!");
             }
            int idx=0;
           InputStream in=new BufferedInputStream(new FileInputStream(file));
           OutputStream out=new BufferedOutputStream(new FileOutputStream(file+"."+idx++));
            int b;
            int count=0;
          while((b=in.read())!=-1) {
                 out.write(b);
                count++;
                if(count % (size *1024)==0) {
                    out.close();
                    out=new BufferedOutputStream(new FileOutputStream(file+"."+idx++));
               }
             }
             in.close();
             out.close();
       }catch(IOException e) {
           e.printStackTrace();
             throw new RuntimeException(e);
         }
     }
     public static void join(String file) {
        try {
            String filename=file.substring(0,file.lastIndexOf(","));
           String num=file.substring(file.lastIndexOf(".")+1);
           int idx=Integer.parseInt(num);
             OutputStream out=new FileOutputStream(filename);
           File f=new File(filename+"."+idx++);
             while(f.exists()){
                 InputStream in=new FileInputStream(f);
                cp(in, out);
                 in.close();
                f=new File(filename+"."+idx++);
           }
             out.close();
        }catch(IOException e) {
            e.printStackTrace();
             throw new RuntimeException(e);
       }
     }
    public static void cp(InputStream in,OutputStream out)throws IOException{
        byte[] buf=new byte[1024*512];
        int count;
        while((count =in.read(buf))!=-1) {
             //System.out.println(count);
             out.write(buf,0,count);
         }
        out.flush();
     }
 }

2.遇到的问题：代码有点看不懂

3.明天继续学习Java