字节流分为FileInputStream 和FileOutputStream

1 package com.io; 2  3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileNotFoundException; 6 import java.io.IOException; 7 import java.io.InputStream; 8 /** 9  * 文件字节流的读取10  * @author ganhang11  *12  */13 public class FileInputStreamDemo {14     public static void main(String[] args) {15         File file=new File("1.txt");16         try {17             InputStream is=new FileInputStream(file);18             byte [] b= new byte[10];19             int len=-1;20             StringBuilder sb=new StringBuilder();//存读取的数据21             while((len=is.read(b))!=-1){22                 sb.append(new String(b,0,len));23             }24             is.close();25             System.out.println(sb);26         } catch (FileNotFoundException e) {27             e.printStackTrace();28         } catch (IOException e) {29             e.printStackTrace();30         }31         32     }33 }

1 package com.io; 2  3 import java.io.File; 4 import java.io.FileNotFoundException; 5 import java.io.FileOutputStream; 6 import java.io.IOException; 7 import java.io.OutputStream; 8 /** 9  * 文件字节流的写入10  * @author ganhang11  *12  */13 public class FileOutputStreamDemo {14     public static void main(String[] args) {15         File file = new File("1.txt");16         if (!file.exists()) {17             try {18                 file.createNewFile();//没有则创建文件19             } catch (IOException e) {20                 e.printStackTrace();21             }22         } else {23             try {24                 OutputStream fos = new FileOutputStream(file, true);//文件末尾添加，不是覆盖25                 byte[] info = "hello,world".getBytes();26                 fos.write(info);27                 fos.close();28                 System.out.println("写入成功！");29             } catch (FileNotFoundException e) {30                 e.printStackTrace();31             } catch (IOException e) {32                 e.printStackTrace();33             }34         }35     }36 }