Java I/O applications of several important streams, java

Java I/O applications of several important streams, java

IO Flowchart

Master 13 Io streams

 

1. FileInputStream and FileoutputStream

FileInputStream: File Reading

1 public class readers 2 {3 public static void main (String [] args) throws Exception 4 {5 File file = new File ("F: \ java \ workspace \ Fanshe \ src \ com \ cyg \ fanshe. java "); // read file 6 FileInputStream fi = new FileInputStream (file); // create a byte stream to open the file 7 byte [] B = new byte [fi. available ()]; // fi. available can be used to obtain the number of bytes occupied by the file. 8 int a =-1; 9 while (a = fi. read (B ))! =-1) // determine whether the file has reached the end of the file 10 {11 // System. out. println (new String (B); 12} 13 System. out. println (new String (B); 14 // disable stream 15 fi. close (); 16 17} 18}

FileoutputStream: file writing

1 public class output 2 {3 public static void main (String [] args) throws Exception 4 {5 File file = new File ("F: \ a.txt "); 6 FileOutputStream out = new FileOutputStream (file); 7 out. write ("abmin ". getBytes (); 8 out. flush (); // clear cache 9 out. close (); // close stream 10} 11}

 

Ii. BufferedInputStream and BufferedOutputStream

BufferedInputStream is a buffer stream.

Function: adds some functions for another input stream, namely buffering input and supportingmark(TAG) andresetThe reset method is implemented through an internal buffer array.

 

 1 public class buffertream 2 { 3     public static void main(String[] args) throws Exception 4     { 5         FileInputStream in = new FileInputStream("E:\\win10 64\\vmware.log"); 6         BufferedInputStream bu = new BufferedInputStream(in); 7         FileOutputStream out = new FileOutputStream("E:\\a.txt"); 8         BufferedOutputStream bo = new BufferedOutputStream(out); 9         10         byte[] b = new byte[1024];11         int a = bu.read(b);12         while(a != -1)13         {14             //System.out.println(Arrays.toString(b));15             bo.write(b, 0, a);16             a = bu.read(b);17         }18         in.close();19         bu.close();20         21         bo.flush();22         out.close();23         bo.close();24     }25 }

The running result is as follows:

 

3. DataOutputStream and DataInputStream

It is a data input stream that inherits FilterInputStream and is used to decorate other input streams.

1 public class adtastream 2 {3 public static void main (String [] args) throws Exception 4 {5 FileOutputStream out = new FileOutputStream ("E: \ B .txt "); 6 DataOutputStream dot = new DataOutputStream (out); // The filter stream must have a node stream 7 8 // write data 9 dot. writeInt (10); 10 dot. writeBytes ("admin"); 11 dot. writeChar ('A'); 12 dot. writeBoolean (true); 13 14 out. flush (); 15 out. close (); 16 dot. close (); 17 18 FileInputStream in = new FileInputStream ("E: \ B .txt"); 19 DataInputStream di = new DataInputStream (in ); 20 21 // when reading data, it must be the same as the write order. Otherwise, the structure 22 System will be damaged. out. println (di. readInt (); 23 System. out. println (di. readByte (); 24 System. out. println (di. readChar (); 25 System. out. println (di. readBoolean (); 26} 27}

 

 

4. ByteArrayInputStream and ByteArrayOutputStream

ByteArrayInputStream is used to read data in memory.

1 public class bytestream 2 {3 public static void main (String [] args) throws Exception 4 {5 ByteArrayOutputStream out = new ByteArrayOutputStream (); 6 String str = "admin "; 7 out. write (str. getBytes (); 8 byte [] B = new byte [200]; 9 ByteArrayInputStream in = new ByteArrayInputStream (str. getBytes (); // ByteArrayInputStream: stream 10 in. read (B); 11 System. out. println (Arrays. toString (B); 12} 13}

The bottom source code of the system corresponding to damin is printed.

 

5. ObjectInputStream and ObjectoutputStream

 

6. BufferedReader and BufferedWriter