Java input/output stream system and java output stream system

Java input/output stream system and java output stream system

When I use java io streams to read and write files, it is always confusing by its various streams. There are more than 40 classes, which have been sorted out. After a while, it will be messy. I decided to sort them out! In case you forget

Java input/output stream system

1. byte stream and byte stream

Byte stream: Read by byte. Refer stream: Read by character.

The byte stream is easy to read and has powerful functions. When the byte stream is not available, you can use Word throttling.

Byte stream base class: InputStream and OutputStream

InputStream method:

 

OutputStream method:

 

Stream base class: Reader and Writer

Reader Method:

 

Writer method:

 

2. Input/output stream system

 

3. Conversion stream

InputStreamReader: byte input stream-> character input stream conversion

OutputStreamWriter: byte output stream-> character output stream conversion

For example: byte input stream> character input stream conversion

It is not convenient to use byte streams, but it is not convenient to read data from common readers. Convert the data into BufferReader and read a row at a time using the Read line () of BufferReader.

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));                String result = "";                String line = "";               while((line = reader.readLine())!= null){                   result = result+ line;               }               System.out.println(result);

InputStream to String:

Private static String changeInputeStream (InputStream inputStream, String encode) {// It is usually called a memory stream, written in the memory ByteArrayOutputStream outputStream = new ByteArrayOutputStream (); byte [] data = new byte [1024]; int len = 0; String result = ""; if (inputStream! = Null) {try {while (len = inputStream. read (data ))! =-1) {outputStream. write (data, 0, len);} // result is the result = new String (outputStream. toByteArray (), encode); outputStream. flush (); outputStream. close (); inputStream. close ();} catch (IOException e) {// TODO Auto-generated catch block e. printStackTrace () ;}} return result ;}

 

InputStream-> StringBuffer:

StringBuffer buffer = new StringBuffer (); InputStreamReader reader = new InputStreamReader (request. getInputStream (), "UTF-8"); char [] requestchar = new char [5]; if (reader! = Null) {System. out. println ("default encoding:" + reader. getEncoding (); // default encoding: UTF8} // buffer reader. readLine () while (temp = reader. read (requestchar ))! =-1) {buffer. append (requestchar, 0, temp); System. out. println (buffer. toString ();} String result = buffer. toString ();

4. file read/write:

Class Kaoshi {public static void main (String [] args) {role in = new role (System. in); int score = 0; // score; StringBuffer answer = new StringBuffer (); // stores the user's answer, dynamic String; String result = "ACDD "; // correct answer; try {FileReader file = new FileReader ("Test.txt"); // open the file; BufferedReader intw = new BufferedReader (file); // buffer the stream, read by row; String s = null; while (s = intw. readLine ())! = Null) {// the judgment is not empty; if (! S. startsWith ("*") {System. out. println (s);} else {System. out. println ("enter the correct answer:"); String str = in. next (); char c = str. charAt (0); // collect answers; answer. append (c) ;}} catch (IOException e) {e. printStackTrace () ;}for (int I = 0; I <result. length (); I ++) {if (result. charAt (I) = answer. charAt (I) | result. charAt (I) = answer. charAt (I)-32) {score + = 25 ;}} System. out. println (score );}}