Java学习笔记——I/O流

时间：2022-03-13 12:03:07

 

朝辞白帝彩云间，千里江陵一日还。
两岸猿声啼不尽，轻舟已过万重山。

　　　　　　　　　　　　　　——早发白帝城

我们老师写代码有个特点，就是简洁。每一句的意图都十分明确。所以他讲课的速度也比较快。

跑题了，说说I/O流:

1、字节输入流

2、字符输入流

3、字节输出流

4、字符输出流

上代码：

 1 public class FileInputStreamAndFileoutputSteamDemo {
 2 
 3     public static void main(String[] args) throws IOException {
 4         FileOutputStream fos = new FileOutputStream("/home/yanshaochen/public/abc.txt");
 5         byte[] bytes = new byte[1024];
 6         bytes = "金麟岂是池中物,一遇风云变化龙".getBytes();
 7         fos.write(bytes);
 8         fos.close();
 9         FileInputStream fis = new FileInputStream("/home/yanshaochen/public/abc.txt");
10         String str = "";
11         int data;
12         while ((data = fis.read(bytes)) != -1) {
13             str += new String(bytes, 0, data);
14         }
15         System.out.println(str);
16         fis.close();
17     }
18 }
 1 public class WriterAndReader {
 2 
 3     public static void main(String[] args) throws IOException {
 4         String path = "/home/yanshaochen/public/abc.txt";
 5         Writer wt = new FileWriter(path);
 6         String str = "AAAAA";
 7         wt.write(str);
 8         wt.close();
 9         Reader rd = new FileReader(path);
10         char[] chars = new char[16];
11         int data;
12         str = "";
13         while ((data = rd.read(chars))!=-1) {
14             str += new String(chars, 0, data);
15         }
16         System.out.println(str);
17         rd.close();
18     }
19 }

带缓冲区的字符输入输出流

 1 public class BufferedReaderAndBufferedWriter {
 2 
 3     public static void main(String[] args) throws IOException {
 4         Writer fw = new FileWriter("/home/yanshaochen/public/abc.txt");
 5         BufferedWriter bw = new BufferedWriter(fw);
 6         String str = "AAAAAAAA";
 7         bw.write(str);
 8         bw.newLine();
 9         bw.close();
10         Reader fr =new FileReader("/home/yanshaochen/public/abc.txt");
11         BufferedReader br = new BufferedReader(fr);
12         while ((str = br.readLine())!= null) {
13             System.out.println(str);
14         }
15         br.close();
16     }
17 }

字节流读写二进制

 1 public class DataInputStreamDemo {
 2 
 3     public static void main(String[] args) throws IOException {
 4         //原始地址
 5         InputStream is = new FileInputStream("/home/yanshaochen/图片/2017-05-06 15-12-02屏幕截图.png");
 6         DataInputStream dis = new DataInputStream(is);
 7         //目标地址
 8         OutputStream os = new FileOutputStream("/home/yanshaochen/public/2017-05-06 15-12-02屏幕截图.png");
 9         DataOutputStream dos = new DataOutputStream(os);
10         byte[] bytes = new byte[1024];
11         int data;
12         while((data = dis.read(bytes)) != -1){
13             dos.write(bytes,0,data);
14         }
15         System.out.println("copy ok!");
16         dos.close();
17         dis.close();
18     }
19 }

 

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