Java使用BufferedInputStream和BufferedOutputStream类进行文件复制

import java.io.*;

public class Copy {

        public static void main(String[] args)throws IOException{

               if(args.length != 2){

                     System. out.println("Usage: java copy sourceFile targetFile" );

                     System. exit(0);

              }

              

              File sourceFile = new File(args[0]);

               if(!sourceFile.exists()){

                     System. out.println("Source file " + args[0] + " not exist");

                     System. exit(0);

              }      

              File targetFile = new File(args[1]);

               if(targetFile.exists()){

                     System. out.println("TargetFile " + args[1] + " already exists");

                     System. exit(0);

              }

              

              BufferedInputStream input = new BufferedInputStream(new FileInputStream(sourceFile));

              

              BufferedOutputStream output = new BufferedOutputStream(new FileOutputStream(targetFile));

              

               int r;

               int numberOfBytesCopied = 0;

              

               while((r = input.read()) != -1){

                     output.write(( byte)r);

                     numberOfBytesCopied++;

              }

              

              input.close();

              output.close();

              System. out.println(numberOfBytesCopied + "  bytes copied" );

       }

}