Java IO (Input output) flow < one >

I. Overview of IO streams

The 1.IO stream is used to transfer data between devices.

The operation of the data in 2.Java is carried out in a stream manner.

3. Classification:

1) data by operation: Byte Stream (There are early, can transmit any data) and character stream (ASCII code table, Unicode code table < two bytes >).

2) Press flow: input stream and output stream.

4. Abstract base class

1) byte stream: Inputstream,outputstream

2) Character stream: Reader,writer

two. Io Stream instance

1.FileWriter class Instances

1    //Create a new Filewriterdemo class2 ImportJava.io.*;3 4  Public classFilewriterdemo {5     6     Public Static voidMain (String []args)throwsioexception{7        //Create a new FileWriter class and create a new file Text.txt8FileWriter fw=NewFileWriter ("Test.txt");9        //writes data to memory, written in memory onlyTenFw.write ("ABCDE"); One        //refreshes the data and writes the data to the file A Fw.flush (); -        //can be written infinitely -Fw.write ("haha"); the  - Fw.flush (); -        //Refresh on shutdown - fw.close (); +        } -}

Run results

2.IO exception

1    //Create a new Filewriterdemo class2 ImportJava.io.*;3 4  Public classFilewriterdemo {5     6     Public Static voidMain (String []args) {7        //defining classes outside of a try8FileWriter fw=NULL;9    Ten        Try{ One           //Initialize Afw=NewFileWriter ("Test.txt"); -        -Fw.write ("ABCDE"); the        } -         -        Catch(IOException e) { -             + System.out.println (e.tostring ()); -        } +       //try to put the closed data stream into the finally when handling the exception A        finally{ at             -             Try {   -                 //If there is more than one, use multiple judgements and not in a single, such as: -                 //if (fw! ==null&&fw== ""), etc. -                   if(fw!=NULL) -                  in fw.close (); -              to}Catch(IOException e) { +                  - System.out.println (e.tostring ()); the             } *           } $        }Panax Notoginseng}

3 Fileread class Instances

3.1 One character read at a time

1 ImportJava.io.*;2  Public classFileRead {3 4      Public Static voidMain (string[] args)throwsioexception{5         //Create a new FileReader class6FileReader fd=NewFileReader ("Test.txt");7         //when the data is read from a file, an int is returned at the end of the data-one that ends8         intCh=0;9          while((Ch=fd.read ())!=-1){TenSystem.out.println ("ch=" + (Char) ch); One         } A         /* - While (true) { - int Ch=fd.read (); the //When ch=-1, roll -out cycle - if (ch==-1) - Break ; - //output read data and force conversion to char type + System.out.println ("ch=" + (char) ch); -         } +         */ A         //Turn off Data flow at fd.close (); -          -         } -          -}

3.2 reading from the array

1 ImportJava.io.*;2 3  Public classFilereadstr {4 5      Public Static voidMain (string[] args)throwsioexception{6          7FileReader fd=NewFileReader ("Test.txt");8         //when reading data in an array, the array is typically defined as 1024 times times the number9         Char[]buf=New Char[1024]; Ten         intNum=0; One          while((Num=fd.read (BUF))!=-1){ A         //from the first start of the array to the end of the last -System.out.println (NewString (buf,0, num)); -         } the          - fd.close (); -     } -  +}

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Java IO (Input output) flow < one >