字节流读写文件

package com.io;  
  
import java.io.*;  
  
public class MyIO {  
  
       
    public static void main(String[] args) {  
        //读取文件  
        int b = 0;  
        FileInputStream in = null;  
        try{  
        in = new FileInputStream("D://java//ThrowsDemo.java");  
        }catch (FileNotFoundException e) {  
        System.out.println("找不到指定文件");  
        System.exit(-1);  
        }  
  
        try{  
        long num = 0;  
        while((b=in.read())!=-1) {  
        System.out.print((char)b);  
        num++;  
        }  
        in.close();  
        System.out.println();  
        System.out.println("共读取了"+num+"个字节");  
  
        }catch (IOException e1) {  
        System.out.println("文件读取出错");System.exit(-1);  
        }  
        //写文件  
        int b1 = 0;  
        FileInputStream in1 = null;  
        FileOutputStream out = null;   
        try{  
        in1 = new FileInputStream("D://java//ThrowsDemo.java");  
        out = new FileOutputStream("D://java//Throw.java");  
        while((b1=in1.read())!=-1) {  
        out.write(b1);  
        }  
        in1.close();  
        out.close();  
        }catch (FileNotFoundException e2) {  
        System.out.println("找不到指定文件");System.exit(-1);  
        }catch(IOException e1) {  
        System.out.println("文件复制出错");System.exit(-1);  
        }  
        System.out.println("文件已复制");  
    }  
  
}