IO流，字节流

 2 /**
 3  * IO流,字节流
 4  */
 5 import java.io.FileInputStream;
 6 import java.io.FileOutputStream;
 7 
 8 public class ByStreamDemo {
 9     public static void main(String[] args) throws Exception{
10 //        demo_write();
11 //        demo_read_1();
12         demmo_read_2();
13     }
14     //写入数据
15     public static void demo_write() throws Exception{
16         //获取文件
17         FileOutputStream fos = new FileOutputStream("F:\\1.txt");
18         //写入数据"abcdefg"
19         fos.write("abcdefg".getBytes());
20         //关闭流
21         fos.close();
22     }
23     //读取数据1
24     public static void demo_read_1() throws Exception{
25         //获取文件
26         FileInputStream fis = new FileInputStream("F:\\1.txt");
27         //声明一个数据类型
28         int ch = 0;
29         //遍历输出
30         while((ch = fis.read()) != -1) {
31             System.out.print((char) ch);
32         }
33     }
34     //获取数据2
35     public static void demmo_read_2() throws Exception{
36         //获取文件
37         FileInputStream fis = new FileInputStream("F:\\1.txt");
38         //声明一个数组
39         byte buf[] = new byte[1024];
40         //声明一个数据类型
41         int len = 0;
42         //遍历输出
43         while((len = fis.read(buf)) != -1) {
44             System.out.println(new String(buf, 0, len));
45         }
46     }
47 }