【java】io流之字节输出流：java.io.OutputStream类及子类java.io.FileOutputStream

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.OutputStream;
 7 
 8 public class TestOutputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11         OutputStream outputStream=new FileOutputStream(file);
12         String str="每天进步一点点！";
13         byte[] bytes=str.getBytes();
14         outputStream.write(bytes);
15         outputStream.close();
16     }
17 }

OutputStream

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.OutputStream;
 7 
 8 public class TestOutputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11         OutputStream outputStream=new FileOutputStream(file);
12         String str="让世界充满爱！";
13         byte[] bytes=str.getBytes();
14         
15 //        outputStream.write(bytes);
16         
17         for(byte b:bytes){
18             outputStream.write(b);//单个字节输出
19         }
20         
21         outputStream.close();
22     }
23 }

单个字节输出

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.OutputStream;
 7 
 8 public class TestOutputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11         OutputStream outputStream=new FileOutputStream(file);
12         String str="让世界充满爱！";
13         byte[] bytes=str.getBytes();
14 //        outputStream.write(bytes, 1, 3);//这样输出中文会有乱码:檬?
15         outputStream.write(bytes, 2, 4);//输出：世界
16         outputStream.close();
17     }
18 }

输出一部分

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.OutputStream;
 7 
 8 public class TestOutputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11         OutputStream outputStream=new FileOutputStream(file,true);//文件内容追加，而不是覆盖。
12         String str="让世界充满爱！";
13         byte[] bytes=str.getBytes();
14         outputStream.write(bytes);
15         outputStream.close();
16     }
17 }

文件内容追加而不是覆盖

 1 package 文件操作;
 2 
 3 import java.io.File;
 4 import java.io.FileOutputStream;
 5 import java.io.IOException;
 6 import java.io.OutputStream;
 7 
 8 public class TestOutputStream {
 9     public static void main(String[] args) throws IOException {
10         File file=new File("D:"+File.separator+"test.txt");
11         OutputStream outputStream=new FileOutputStream(file,true);//文件内容追加，而不是覆盖。
12         String str="让世界充满爱！
";//每次输出写回文件换行
13         byte[] bytes=str.getBytes();
14         outputStream.write(bytes);
15         outputStream.close();
16     }
17 }

每次输出内容到文件换行追加

字节流可以不用关闭操作即可将内容写进文件。