当前位置：网站首页>I/o case practice

I/o case practice

2022-07-25 21:42:00 【51CTO】

       
       /*
       
* author ： Stupid teacher 
       
*csdn Certified Instructor 
       
*51cto Senior lecturer 
       
* Tencent classroom certified lecturer 
       
* Netease cloud classroom certified lecturer 
       
* Certified lecturer of Huawei developer school 
       
* Member of iqiyi thousand talents master plan 
       
* Here to share technology 、 Knowledge and life 
       
* All kinds of dry goods , Remember to pay attention ！
       
*/
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

I/O Case practice _ Converted flow

Create a byte output stream object associated with a file FileOutputStream fos = new
FileOutputStream("c:\\cn8.txt"); // Create a conversion stream object that can convert characters to bytes , And specify the code
OutputStreamWriter osw = new OutputStreamWriter(fos,"utf-8");
Call transformation flow , Write the words out , It is actually written to the buffer of the conversion stream osw.write(" Hello ");// Write buffer . osw.close();
Create a byte stream object to read the file

       
       try {
       
       in 
       
       = 
       
       new 
       
       FileInputStream(
       
       "d:/aa/5.txt");
       
       //  Create a transformation flow object 
       
       // InputStreamReader isr = new
       
       // InputStreamReader(in); Create objects like this , Read with local default code table , Error decoding error will occur 
       
       InputStreamReader 
       
       isr 
       
       = 
       
       new 
       
       InputStreamReader(
       
       in, 
       
       "gbk");
       
       //  Use conversion stream to read bytes in byte stream 
       
       int 
       
       ch 
       
       = 
       
       0;
       
       while ((
       
       ch 
       
       = 
       
       isr.
       
       read()) 
       
       != 
       
       -
       
       1) {
       
       System.
       
       out.
       
       println((
       
       char) 
       
       ch);
       
            }
       
       //  Closed flow 
       
       isr.
       
       close();
       
        } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        } 
       
       catch (
       
       UnsupportedEncodingException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.

I/O Case practice _ Output stream _02

Character output stream

       
       // TODO Auto-generated method stub
       
       File 
       
       file 
       
       = 
       
       new 
       
       File(
       
       "d:/aa/5.txt");
       
       try {
       
       //  Character output stream 
       
       FileWriter 
       
       fileWriter 
       
       = 
       
       new 
       
       FileWriter(
       
       file, 
       
       true); 
       
       //  Character output stream 
       
       // true Represents the addition of 
       
       fileWriter.
       
       write(
       
       " Hello ");
       
       fileWriter.
       
       close();
       
       //  Byte output stream 
       
       FileOutputStream 
       
       fileOutputStream 
       
       = 
       
       new 
       
       FileOutputStream(
       
       file, 
       
       true);
       
       fileOutputStream.
       
       write(
       
       'a');
       
       fileOutputStream.
       
       close();
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.

I/O Case practice _ Converted flow _03

Character input stream

       
       // Character input stream   read   Reading and writing text files (.java .txt...)
       
       //1. Create objects 
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/4.txt");
       
       //2. Create character input stream object 
       
       try {
       
       FileReader 
       
       fileReader
       
       =
       
       new 
       
       FileReader(
       
       file);
       
       int 
       
       a;
       
       a
       
       = 
       
       fileReader.
       
       read(); 
       
       // Read a character 
       
       System.
       
       out.
       
       println((
       
       char)
       
       a);
       
       char[] 
       
       arr
       
       =
       
       new 
       
       char[
       
       3];
       
       fileReader.
       
       read(
       
       arr);
       
       // Read multiple characters into the array 
       
       System.
       
       out.
       
       println(
       
       new 
       
       String(
       
       arr));
       
       // Loop reading the contents of the file 
       
       while((
       
       a
       
       =
       
       fileReader.
       
       read())
       
       !=-
       
       1)
       
       System.
       
       out.
       
       println((
       
       char)
       
       a);
       
       fileReader.
       
       close();
       
        } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
        }
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.

Character output stream + file

       
       // Character output stream   Write 
       
       //1. Create a file object 
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/5.txt");
       
       //2. Create character output stream 
       
       try {
       
       FileWriter 
       
       fileWriter
       
       =
       
       new 
       
       FileWriter(
       
       file);
       
       fileWriter.
       
       write(
       
       "bb\r\n"); 
       
       // Line break  
       
       fileWriter.
       
       write(
       
       " lovely ");
       
       fileWriter.
       
       close();
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.

I/O Case practice _ Converted flow _04

       
       // Byte input stream   Read data from the file   A byte by byte read  ( picture   Reading and writing of video files )
       
       //( An English character or numeric character corresponds to a byte   A Chinese character corresponds to two bytes , So read Chinese with character stream ) 
       
       //1. Create a file object 
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/2.txt");    
       
       //2. Create an input stream object 
       
       try {
       
       FileInputStream 
       
       fileInputStream
       
       =
       
       new 
       
       FileInputStream(
       
       file);
       
       //3. Reading data 
       
       int 
       
       a
       
       =
       
       fileInputStream.
       
       read(); 
       
       // Read the next character   Read the return of the current character ascII code   Read to the end of the file   Then return to -1
       
       System.
       
       out.
       
       println((
       
       char)
       
       a);
       
       a
       
       =
       
       fileInputStream.
       
       read();
       
       System.
       
       out.
       
       println((
       
       char)
       
       a);
       
       // Read multiple bytes into the array 
       
       byte[] 
       
       arr
       
       =
       
       new 
       
       byte[
       
       3];
       
       fileInputStream.
       
       read(
       
       arr); 
       
       // Read 3 Bytes in arr Array 
       
       System.
       
       out.
       
       println(
       
       new 
       
       String(
       
       arr, 
       
       0, 
       
       3));
       
       // Read entire file 
       
       while((
       
       a
       
       =
       
       fileInputStream.
       
       read())
       
       !=-
       
       1)
       
       System.
       
       out.
       
       print((
       
       char)
       
       a);        
       
       // Close file 
       
       fileInputStream.
       
       close();
       
    } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
    } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.

I/O Case practice _ Array _05

Byte output stream + File operations

       
       // Byte output stream   Write data to a file 
       
       //1. Create a file object 
       
       File 
       
       file
       
       =
       
       new 
       
       File(
       
       "d:/aa/3.txt");
       
       //2. Create a byte output stream 
       
       try {
       
       FileOutputStream 
       
       fileOutputStream
       
       =
       
       new 
       
       FileOutputStream(
       
       file);
       
       //3. Write content 
       
       fileOutputStream.
       
       write(
       
       'a'); 
       
       // Write one byte at a time 
       
       byte[] 
       
       arr
       
       =
       
       new 
       
       byte[]{
       
       'b',
       
       'c',
       
       'd'}; 
       
       // Write a byte An array of types 
       
       String 
       
       string
       
       =
       
       "daimeng";
       
       byte[] 
       
       brr
       
       =
       
       string.
       
       getBytes(); 
       
       // You can convert strings into byte arrays 
       
       fileOutputStream.
       
       write(
       
       brr);
       
       fileOutputStream.
       
       close(); 
       
       // Closed flow  
       
  } 
       
       catch (
       
       FileNotFoundException 
       
       e) {
       
       // TODO Auto-generated catch block
       
       e.
       
       printStackTrace();
       
  } 
       
       catch (
       
       IOException 
       
       e) {
       
       // TODO Auto-generated catch block
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.