一、需要用到的類
java.awt.image.BufferedImage;
javax.imageio.ImageIO;
java.io.*;
二、為什么要將BufferedImage轉(zhuǎn)為byte數(shù)組
在傳輸中，圖片是不能直接傳的，因此需要把圖片變?yōu)樽止?jié)數(shù)組，然后傳輸比較方便；只需要一般輸出流的write方法即可；
而字節(jié)數(shù)組變成BufferedImage能夠還原圖像；
三、如何取得BufferedImage
BufferedImage image = ImageIO.read(new File("1.gif"));
四、BufferedImage ---->byte[]
ImageIO.write(BufferedImage image,String format,OutputStream out);方法可以很好的解決問題；
參數(shù)image表示獲得的BufferedImage；
參數(shù)format表示圖片的格式，比如“gif”等；
參數(shù)out表示輸出流，如果要轉(zhuǎn)成Byte數(shù)組，則輸出流為ByteArrayOutputStream即可；
執(zhí)行完后，只需要toByteArray()就能得到byte[];
五、byte[] ------>BufferedImage
ByteArrayInputStream in = new ByteArrayInputStream(byte[]b); //將b作為輸入流；
BufferedImage image = ImageIO.read(InputStream in); //將in作為輸入流，讀取圖片存入image中，而這里in可以為ByteArrayInputStream();
六、顯示BufferedImage
public void paint(Graphics g){
super.paint(g);
g.drawImage(image); //image為BufferedImage類型
}
七、實例
要求：編寫一個網(wǎng)絡程序，通過Socket將圖片從服務器端傳到客戶端，并存入文件系統(tǒng)；
Server端：
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(8888);
Socket s = server.accept();
DataOutputStream dout = new DataOutputStream(s.getOutputStream());
BufferedImage image = ImageIO.read(new File("1.gif"));
ByteArrayOutputStream out = new ByteArrayOutputStream();
boolean flag = ImageIO.write(image, "gif", out);
byte[] b = out.toByteArray();
dout.write(b);
s.close();
}
}
Client端：
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.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;
MyPanel panel;
public T6Client() {
setSize(300, 400);
button = new JButton("獲取圖像");
add(button,BorderLayout.NORTH);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
try {
Socket s = new Socket("localhost",8888);
PrintWriter out = new PrintWriter(s.getOutputStream());
out.print("a");
DataInputStream in = new DataInputStream(s.getInputStream());
byte[]b = new byte[1000000];
in.read(b);
ByteArrayInputStream bin = new ByteArrayInputStream(b);
BufferedImage image = ImageIO.read(bin);
ImageIO.write(image, "gif", new File("2.gif"));
s.close();
} catch (Exception e) {
}
}
});
panel = new MyPanel();
add(panel);
}
public static void main(String[] args) throws Exception {
T6Client frame = new T6Client();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}