把一个文件的每个字节全部变成字节0，出问题了SOS

Question

请高手帮我看下这个程序，是把一个文件的每个字节全部变成字节0，用ultraedit打开看多出了很多个字节0，程序运行时间很长，小虾不胜感激！！package test1;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;/**
 *
 * @author Administrator
 */
public class Test1 {    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
            // TODO code application logic here
            int i = 0;
            FileInputStream fis = null;
            FileOutputStream fos = null;
            try {
                fis = new FileInputStream("c:\\Test1.dat");
                while (fis.read() != -1) {
                    i++;
                }
                System.out.println(i + " " );
            } catch (FileNotFoundException ex) {
                Logger.getLogger(Test1.class.getName()).log(Level.SEVERE, null, ex);
            } catch (IOException e) {
            } finally {                try {
                    fis.close();
                } catch (IOException ex) {
                    Logger.getLogger(Test1.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        try
            { 
                fos = new FileOutputStream("c:\\Test1.dat");
                for(int j = 0;j < i;i++){
                    fos.write(0);
                }
              
            } catch (FileNotFoundException ex) {
                Logger.getLogger(Test1.class.getName()).log(Level.SEVERE, null, ex);
            }catch(IOException e){
                System.out.println(e.getMessage());
            }finally {                try {
                    fos.close();
                } catch (IOException ex) {
                    Logger.getLogger(Test1.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        
        
    }    }

Answer 1

for(int j = 0;j < i;i++){
                    fos.write(0);
                }