Java Learning Note (ix): Java stream, file, and IO

Java console input is completed by system.in.

To get a character stream bound to the console, you can wrap the system.in in a BufferedReader object to create a character stream. Need to import this bag

import Java.io.BufferedReader;

Here is the basic syntax for creating BufferedReader:

New BufferedReader (new InputStreamReader (system.in));

Once the BufferedReader object is created, we can use the read () method to read a character from the console or to read a string with the ReadLine () method.

Example: Use the Read () method to continuously read a single character from the console until the user enters "Q".

1 ImportJava.io.*;2 3  Public classtest{4      Public Static voidMain (string[] args)throwsioexception{5         CharC;6BufferedReader br =NewBufferedReader (NewInputStreamReader (system.in));7SYSTEM.OUT.PRINTLN ("input character, press ' Q ' key to exit.) ");8          Do {9c = (Char) Br.read ();Ten System.out.println (c); One} while(c! = ' Q '); A     } -}

Run:

Fffffgfffffg

Example: Read and display the word lines until you enter the word "end".

1 ImportJava.io.*;2 3  Public classtest{4      Public Static voidMain (string[] args)throwsioexception{5BufferedReader br =NewBufferedReader (NewInputStreamReader (system.in));6 String str;7System.out.println ("Enter lines of text."));8System.out.println ("Enter ' End ' to quit."));9          Do {Tenstr =br.readline (); One System.out.println (str); A} while(!str.equals ("End")); -     } -}

Run:

Aaaaaaaabbbbbbbbbbendend

Read and write files

Example: InputStream and OutputStream write read file:

1 ImportJava.io.*;2 3  Public classtest{4      Public Static voidMain (string[] args)throwsioexception{5         /**6 * Write File7          */8File f =NewFile ("Test.txt");9         //build FileOutputStream object, file does not exist automatically newTenFileOutputStream FOP =NewFileOutputStream (f); One         //Build the OutputStreamWriter object, parameters can specify that encoding default encoding is Windows GBK AOutputStreamWriter writer =NewOutputStreamWriter (FOP, "UTF-8"); -         //Write to Buffer -Writer.append ("Chinese Input:"); the         //line Break -Writer.append ("\ r \ n"); -         //Write to Buffer -Writer.append ("中文版")); +         //Close closes the write stream, which writes the contents of the buffer to the file - writer.close (); +         //turn off the output stream A fop.close (); at  -         /** - * read out the file -          */ -         //Building FileInputStream Objects -FileInputStream FIP =NewFileInputStream (f); in         //build the InputStreamReader object with the same encoding as the write -InputStreamReader reader =NewInputStreamReader (FIP, "UTF-8"); to         //Create a string StringBuffer object +StringBuffer SB =NewStringBuffer (); -          while(Reader.ready ()) { the             //go to char and add to StringBuffer object *Sb.append ((Char) Reader.read ()); $         }Panax Notoginseng         //Output File Contents - System.out.println (sb.tostring ()); the         //turn off Read stream + reader.close (); A         //close the input stream and release system resources the fip.close (); +     } -}

Run output:

Chinese input: 中文版

Java Learning Note (ix): Java stream, file, and IO