//从文件里读数据，显示到屏幕上
package com.yourcompany.core;

import java.io.*;

public class think {
 
 public static void main(string[] args) {
  
  try {
   
   fileinputstream file = new fileinputstream("d://sss.txt");
   char[] c = new char[file.available()];
   for (int i = 0 ; i<c.length;i++) {
    c[i] = (char)file.read();
    
   }
   system.out.print(c);
   
  }
  catch(filenotfoundexception e) {
   
   e.printstacktrace();
  }
  catch(ioexception e) {
   
   e.printstacktrace();
  }
  
 }
}
//在屏幕上写东西到文件中
package com.yourcompany.core;

import java.io.*;
import java.util.*;

public class think {
 
 public static void main(string[] args) {
  
  try {
   
   byte[] c = new byte[1000] ;
   system.in.read(c);
   fileoutputstream file = new fileoutputstream("d://s.txt");
   file.write(c);
  }
  catch(exception e) {
   e.printstacktrace();
  }
 }
}
//从一个文件复制到另一个文件
package com.yourcompany.core;

import java.io.*;
import java.util.*;

public class think {
 
 public static void main(string[] args) {
  
  try {
   
   fileinputstream file = new fileinputstream("d://sss.txt");
   fileoutputstream fileout = new fileoutputstream("d://aaa.txt");
   byte[] c = new byte[file.available()];
   for(int i = 0;i<c.length;i++) {
    c[i] = (byte)file.read();
   }
   fileout.write(c);
  }
  catch(exception e) {
   e.printstacktrace();
  }
 }
}
//在屏幕上你输入什么我就输入什么
package com.yourcompany.core;

import java.io.*;
import java.util.*;

public class think {
 
 public static void main(string[] args) {
  
  try {
   
   byte [] c = new byte[1000];
   int cc = system.in.read(c);
   for (int i=0;i<cc;i++) {
    system.out.print((char)c[i]);
   }
  }
  catch(exception e) {
   e.printstacktrace();
  }
  
 }
}