Character stream of Java io

  1. Character Stream

In the program a character equals two bytes, Java provides us with reader and writer two classes dedicated to manipulating character streams

1) Character output stream: Writer

Writer is a character stream, which is an abstract class, so to use it, it must also be instantiated by its subclass before it can be used.

common methods of writer class

Method Name	Description
Public abstract void Close () throws IOException	Turn off the output stream
Public void Write (String str) throws IOException	Output a string
Public void Write (char cbuf) throws IOException	Output a character array
Public abstract void Flush () throws IOException	Mandatory empty Cache

Example 1:helloworld

Writing data to a text file through a character output stream

[Java]  View Plain copy print?

2. public static void Main (string[] args ) throws Exception {
4.   
6. //Declare a file object
8.   
10. File File = new file ("Hellowolrd.txt");
12.   
14.   
16.   
18. //Declare a Write Object
20.   
22. writer writer = null;
24.   
26. //Use the FileWriter class to instantiate an object of the writer class and write it in an appended form
28.   
30. writer = new FileWriter (file, true);
32.   
34.   
36.   
38. //Declare a string to write
40.   
42. string str = "Write HelloWorld in string form";
44.   
46. //write in a text file
48.   
50. writer.write (str);
52.   
54. //Refresh
56.   
58. Writer.flush ();
60.   
62. //close character output stream
64.   
66. Writer.close ();
68.   
70. }  

2) character input stream: Reader

Reader itself is also an abstract class, and similarly, if you use it, we need to instantiate it by its subclass to use it.

Common methods of reader class

Method Name	Description
Public abstract void Close () throws IOException
public int Read () throws IOException
public int Read (char cbuf) throws IOException

Through the method we see that the reader class only provides a way to read characters

Example 2: or HelloWorld

Read the contents of the text on top of it and display it on the console

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2. public static void Main (string[] args) Throws Exception {
4.   
6. //Declare a file object
8.   
10. File File = new file ("Hellowolrd.txt");
12.   
14.    
16.   
18. //Declare an object of a reader class
20.   
22. Reader reader = null;
24.   
26.    
28.   
30. //Instantiate reader object by FileReader subclass
32.   
34. reader = new filereader (file);
36.   
38.    
40.   
42. //Declare a character array
44.   
46. char[] c = new char[1024x768];
48.   
50. //// outputs the content
52.   
54. //int len = Reader.read (c);   
56.   
58.          
60.   
62. //Loop mode one read
64.   
66. int len=0;
68.   
70. int temp=0;
72.   
74. While ((Temp=reader.read ())!=-1) {
76.   
78.              
80.   
82. c[len]= (char) temp;
84.   
86. len++;
88.   
90.        }  
92.   
94. //Close input stream
96.   
98. Reader.close ();
100.   
102. //Convert char array to string output
104.   
106. System.out.println (new String (c, 0, Len));
108.   
110.    
112.   
114.     }  

2. The difference between a character stream and a byte stream

The operation of the byte stream operation does not use the buffer itself, it is the direct operation of the file itself, and the byte stream is used to buffer the operation.

If we do not close the stream while manipulating the character stream, the data we write cannot be saved. So you must remember to close the stream when you manipulate the character stream.

Character stream of Java io