Java学习之IO字节流

字节流分为FileInputStream 和FileOutputStream

 package com.io;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.InputStream;

 /**

  * 文件字节流的读取

  * @author ganhang

  *

  */

 public class FileInputStreamDemo {

     public static void main(String[] args) {

         File file=new File("1.txt");

         try {

             InputStream is=new FileInputStream(file);

             byte [] b= new byte[10];

             int len=-1;

             StringBuilder sb=new StringBuilder();//存读取的数据

             while((len=is.read(b))!=-1){

                 sb.append(new String(b,0,len));

             }

             is.close();

             System.out.println(sb);

         } catch (FileNotFoundException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         }

     }

 }

 package com.io;

 import java.io.File;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStream;

 /**

  * 文件字节流的写入

  * @author ganhang

  *

  */

 public class FileOutputStreamDemo {

     public static void main(String[] args) {

         File file = new File("1.txt");

         if (!file.exists()) {

             try {

                 file.createNewFile();//没有则创建文件

             } catch (IOException e) {

                 e.printStackTrace();

             }

         } else {

             try {

                 OutputStream fos = new FileOutputStream(file, true);//文件末尾添加，不是覆盖

                 byte[] info = "hello,world".getBytes();

                 fos.write(info);

                 fos.close();

                 System.out.println("写入成功！");

             } catch (FileNotFoundException e) {

                 e.printStackTrace();

             } catch (IOException e) {

                 e.printStackTrace();

             }

         }

     }

 }