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();
             }
         }
     }
 }