Java I/O article 2 (buffer stream random stream array Stream Data Stream), java Article 2

Java I/O article 2 (buffer stream random stream array Stream Data Stream), java Article 2

1: Buffer stream BufferedReader BufferedWriter

Strong read/write capability, able to read and write a single row of data separately, can reduce the number of visits to the hard disk.

1/** 2 * The buffer stream enhances the readability of the price data, reduces the number of visits to the hard disk, and improves the efficiency. 3 **/4 public static void bufferedDemo () throws IOException {5 File fread = new File ("E: \ input.txt"); 6 File fwrite = new File ("E: \ output.txt"); 7 System. out. println ("file:" + "E: \ output.txt" + "readable" + fwrite. canWrite (); 8 BufferedReader bis = null; 9 BufferedWriter bos = null; 10 FileReader FCM = new FileReader (fread); 11 FileWriter fos = new FileWriter (fwrite); 12 bis = New BufferedReader (FCM); 13 bos = new BufferedWriter (fos); 14 // read file data, print display 15 int lineLen = 0; 16 String arrayStr [] = new String [20]; // create an array and store the read content 17 String temp; 18 while (temp = bis. readLine ())! = Null) {19 System. out. println (temp); 20 arrayStr [lineLen] = temp; 21 lineLen ++; 22} 23 System. out. println ("File Read completed"); 24 // output data 25 String s; 26 while (s = bis. readLine ())! = Null) {27 bos. write (s); 28 bos. newLine (); // insert linefeed 29} 30 System. out. println ("data output is complete. "); 31 bos. flush (); 32 bis. close (); 33 bos. close (); 34}

 

2: Random stream RandomAccessFile

A RandomAccessFile stream that can read data in a file or write data into a file.

1/** 2 * random stream readable and writable type RandomAccessFile 3 * @ throws IOException 4 **/5 public static void RandomAccessDemo () throws IOException {6 // use Random to write some data separately. 7 int data [] = {1, 2, 4, 5, 6, 7, 8, 9} is read }; 8 File fileName = new File ("E: \ RandomAccessFile.txt"); 9 if (! FileName. exists () 10 fileName. createNewFile (); 11 RandomAccessFile raf = new RandomAccessFile (fileName, "rw"); 12 for (int I = 0; I <data. length; I ++) {13 raf. writeInt (I); 14} 15 System. out. println ("Data Writing is complete. "); 16 // read data 17 for (int j = data. length-1; j> = 0; j --) {18 raf. seek (j * 4); 19 System. out. printf ("\ t % d", raf. readInt (); 20} 21 raf. close (); 22}

 

3: array stream byte array stream: ByteArrayInputStream ByteArrayOutputStream

Character array stream: BytearrayReader ByteArrayWriter

1/** 2 * array stream byte array stream (ByteArrayInputStream ByteArrayOutputStream) 3 * character array stream (BytearrayReader ByteArrayWriter) 4 **/5 public static void ByteArrayDemo () throws Exception {6 // byte stream 7 ByteArrayOutputStream bos = new ByteArrayOutputStream (); 8 byte [] str = "Wish you a happy holiday ". getBytes (); 9 bos. write (str); // write data 10 // read data 11 ByteArrayInputStream bis = new ByteArrayInputStream (bos. toByteArray (); 12 byte [] B = new byte [bos. to ByteArray (). length]; 13 bis. read (B); 14 System. out. println ("written data:" + new String (B); 15 bis. close (); 16 bos. close (); 17 // bytes stream 18 CharArrayWriter caw = new CharArrayWriter (); 19 char [] str2 = "happy Mid-Autumn Festival! ". ToCharArray (); 20 caw. write (str2); 21 CharArrayReader car = new CharArrayReader (caw. toCharArray (); 22 char [] c = new char [caw. toCharArray (). length]; 23 car. read (c); 24 System. out. println ("read data:" + new String (c); 25 car. close (); 26 caw. close (); 27}

4: Data Stream DataInputStream DataOutputStream

It can easily read machine-independent java raw data without the need to tangle the size of bytes during reading.

/*** Data stream DataInputStream DataOutputStream can easily read original machine-independent java data **/public static void DataDemo () throws IOException {// create a file, use data streams to write different types of data and read different types of data File f = new File ("E: \ DataDemo.txt"); FileOutputStream fos = new FileOutputStream (f ); dataOutputStream dos = new DataOutputStream (fos); dos. writeInt (23); dos. writeDouble (1, 22.343435); dos. writeFloat (55.2343f); dos. writeBoolean (true); dos. writeChars ("happy Mid-Autumn Festival ! "); System. out. println (" the data has been read! "); // Read data FileInputStream FD = new FileInputStream (f); DataInputStream dis = new DataInputStream (FS); System. out. println (dis. readInt (); System. out. println (dis. readDouble (); System. out. println (dis. readFloat (); System. out. println (dis. readFloat (); System. out. println (dis. readBoolean (); char c = '\ 0'; while (c = dis. readChar ())! = '\ 0') {System. out. print (c);} dis. close (); dos. close ();}