FileOutputStream

 1 package file;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 
 7 public class Demo2 {
 8     public static void main(String[] args) throws IOException {
 9 //        writeTest1();
10 //        writeTest2();
11         writeTest3();
12     }
13     
14 
15     //使用字节数组把数据写出
16     public static void writeTest3() throws IOException   {
17         File file = new File("F:/2.txt");
18         FileOutputStream fileOutputStream = new  FileOutputStream(file);
19         //数据写出
20         String data = "abcd";
21         byte[] buf = data.getBytes();
22         fileOutputStream.write(buf, 0, 2);    //写出2个字节
23         fileOutputStream.close();
24     }
25     
26     //使用字节数组把数据写出
27     public static void writeTest2() throws IOException   {
28         File file = new File("F:/2.txt");
29         //使用FileOutputStream(File)，如果文件不存在，会自动创建目标文件。如果存在，则会先把目标文件的内容清空，再写内容
30         //使用FileOutputStream(File，true)构造函数，则会在末尾追加
31         FileOutputStream fileOutpubStream = new FileOutputStream(file);
32         //数据写出
33         String data = "hello world";
34         fileOutpubStream.write(data.getBytes());
35         //关闭资源         
36         fileOutpubStream.close();
37     }
38     
39     //每次只能写一个字节数据
40     public static void writeTest1() throws IOException   {
41         File file = new File("F:\\2.txt");
42         FileOutputStream fileOutpubStream = new FileOutputStream(file);
43         fileOutpubStream.write(‘h‘);
44         fileOutpubStream.write(‘e‘);
45         fileOutpubStream.write(‘l‘);
46         fileOutpubStream.write(‘l‘);
47         fileOutpubStream.write(‘o‘);
48         
49         fileOutpubStream.close();
50     }
51 }