二进制文件的读写

1.把浮点数写入文件

import java.io.*;

public class FileOutputDemo
{
public static void main(String[] args)
{
   FileOutputStream out;
   DataOutputStream p;

   try
   {
    out = new FileOutputStream("myfile.txt");
    p = new DataOutputStream(out);
    p.writeDouble(3);
    p.writeDouble(4);
    p.writeDouble(5);
    p.close();
   }
   catch(Exception e)
   {
    System.err.println("Error writing to file");
   }
}
}

2.从文件中读取浮点数

import java.io.*;

public class FileInputDemo
{
public static void main(String[] args)
{
   if(args.length==1)
   {
    try
    {
     FileInputStream f = new FileInputStream(args[0]);
     DataInputStream in = new DataInputStream(f);
     while(in.available() != 0)
     {
      System.out.println(String.valueOf(in.readDouble()));
     }
     in.close();
    }
    catch(Exception e)
    {
     System.out.println("File input Erroe!");
    }
   }
   else
    System.out.println("Invalid parametres");
}
}