【java】io流之字节输入流：java.io.InputStream类及子类java.io.FileInputStream

 1 package 文件操作;
 2
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.IOException;
 6 import java.io.InputStream;
 7
 8 public class TestInputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11
12         /*一次性读取文件内容
13         if(file.exists()){
14             InputStream inputStream=new FileInputStream(file);
15             byte[] bytes=new byte[1024];
16             int length=inputStream.read(bytes);
17             inputStream.close();
18             System.out.println("【"+new String(bytes,0,length)+"】");
19         }
20         */
21
22         if(file.exists()){//单个读取
23             InputStream inputStream=new FileInputStream(file);
24             byte[] bytes=new byte[1024];
25             int foot=0;
26             byte tmp=0;
27             while((tmp=(byte)inputStream.read())!=-1)
28                 bytes[foot++]=tmp;
29             inputStream.close();
30             System.out.println("【"+new String(bytes,0,foot)+"】");
31         }
32     }
33 }