day21 Java learning (IO (character stream))

IO streams (character stream FileReader)

    Jifuryu:

           * Character stream that can read and write IO streams characters directly.

           * Character stream to read characters, you must first read byte data, and then converted to a character, if you want to write a character, you need to re-byte character to write.

    Under what circumstances the use of character streams:

           * Character stream can also copy files, but not recommended, because the characters will Byte to read, write Shihai put back byte characters.

            * Program needs to read a text, or need to write a piece of text can be used when a character stream

            * When reading is read in accordance with the size of the characters, does not appear half Chinese.

            * Write when you can write directly to the string, not into a byte array.

      Precautions:

            * Can not copy files that are not in plain text. (File garbled)

IO streams (character stream FileWriter)

           *  FileWriter class write () method can be automatically converted to character bytes written.

  

public  static  void main (String [] args) throws IOException {
         // A method of automatically generating stubs TODO 
        FileWriter FW = new new FileWriter ( "eee.txt");   // Create File 
        fw.write ( "a happy June");                         / / the Write (): the characters into bytes. 
        fw.close ();                                // release resources 
    }

hosts ()

 

IO streams (character stream copy)

public  static  void main (String [] args) throws IOException { 
        the FileReader fr = new new the FileReader ( "test.txt" );   
        FileWriter FW = new new FileWriter ( "eeecc.txt" ); 
         int B;
         the while ((B = fr.read ! ()) = -1 ) { 
            fw.write (B); 
        } 
        fr.close (); 
        fw.close ();     // must be closed, if none of the stream, it will write the contents of the buffer, flow off It will refresh the buffer contents, then close. 
    }

example

 

IO streams (custom character array copies)

public static void main(String[] args) throws IOException {
        FileReader list = new FileReader("test.txt");
        FileWriter list2 = new FileWriter("copy.txt");
        char[] arr = new char[1024];
        int len;
        while ((len = list.read(arr)) != -1) {
            list2.write(arr, 0, len);
        }
        list.close();
        list2.close();
    }

example