Mutual transfer between bufferedimage and byte []

I. classes to be used

Java. AWT. image. bufferedimage;

Javax. ImageIO. ImageIO;

Java. Io .*;

Ii. Why should I convert bufferedimage into a byte array?

During transmission, Images cannot be directly transmitted. Therefore, you need to change the image to a byte array for convenient transmission. You only need the write method of the output stream;

The byte array becomes bufferedimage, which can restore the image;

3. How to obtain bufferedimage

Bufferedimage image = ImageIO. Read (new file ("1.gif "));

4. bufferedimage ----> byte []

ImageIO. Write (bufferedimage image, string format, outputstream out); this method can solve the problem well;

The image parameter indicates the obtained bufferedimage;

The format parameter indicates the image format, such as "GIF;

The out parameter indicates the output stream. to convert it to a byte array, the output stream is bytearrayoutputstream;

After execution, you only need tobytearray () to get byte [];

5. byte [] ------> bufferedimage

Bytearrayinputstream in = new bytearrayinputstream (byte [] B); // use B as the input stream;

Bufferedimage image = ImageIO. Read (inputstream in); // use in as the input stream to read the image and store it in the image. Here, in can be bytearrayinputstream ();

6. Display bufferedimage

Public void paint (Graphics g ){

Super. Paint (g );

G. drawimage (image, X, Y, width, height, null); // The image is of the bufferedimage type.

}

To automatically call the paint method, you must callRepaint() Method;

VII. Instances

Requirement: Write a network program, upload images from the server to the client through socket, and store the images to the file system;

Server:

Package Org. exam3; import Java. AWT. image. bufferedimage; import Java. io. bytearrayoutputstream; import Java. io. dataoutputstream; import Java. io. file; import java.net. serversocket; import java.net. socket; import javax. imageIO. imageIO; public class t6server {public static void main (string [] ARGs) throws exception {serversocket Server = new serversocket (8889); system. out. println ("the Server opens the connection... port: 8889 "); socket S = server. accept (); While (true) {system. out. println ("a client connects to the server and the server transmits images... "); dataoutputstream dout = new dataoutputstream (S. getoutputstream (); bufferedimage image = ImageIO. read (new file ("1.gif"); // read 1.gif and transmit bytearrayoutputstream out = new bytearrayoutputstream (); Boolean flag = ImageIO. write (image, "GIF", out); byte [] B = out. tobytearray (); dout. write (B); S. close (); system. out. println ("after the image is transferred, the server opens the connection... port 8889 "); s = server. accept ();}}}

Client:

Package Org. exam3; import Java. AWT. borderlayout; import Java. AWT. graphics; import Java. AWT. event. actionevent; import Java. AWT. event. actionlistener; import Java. AWT. image. bufferedimage; import Java. io. bytearrayinputstream; import Java. io. bytearrayoutputstream; import Java. io. datainputstream; import Java. io. file; import Java. io. printwriter; import java.net. socket; import javax. imageIO. imageIO; import javax. swing. Jbutton; import javax. swing. jframe; import javax. swing. jpanel; public class t6client extends jframe {jbutton button; jpanel Panel; int COUNT = 0; bufferedimage image; Public t6client () {setsize (300,400 ); button = new jbutton ("Get image"); add (button, borderlayout. north); button. addactionlistener (New actionlistener () {public void actionreceivmed (actionevent event) {try {socket S = new socket ("localhost", 8889); PR Intwriter out = new printwriter (S. getoutputstream (); out. print ("A"); datainputstream in = new datainputstream (S. getinputstream (); byte [] B = new byte [1024]; bytearrayoutputstream bout = new bytearrayoutputstream (); int length = 0; while (length = in. read (B ))! =-1) {bout. write (B, 0, length);} bytearrayinputstream bin = new bytearrayinputstream (bout. tobytearray (); image = ImageIO. read (BIN); repaint (); ImageIO. write (image, "GIF", new file ("output-" + Count + ". GIF "); count ++; S. close () ;}catch (exception e) {}}); Panel = new jpanel (); add (panel) ;}@ overridepublic void paint (Graphics g) {super. paint (g); G. drawimage (image, 20, 20,300,150, null); // image is of the bufferedimage type} public static void main (string [] ARGs) throws exception {t6client frame = new t6client (); frame. setdefaclocloseoperation (jframe. exit_on_close); frame. setvisible (true );}}