BufferedImage與byte[]互轉

一、需要用到的類

java.awt.image.BufferedImage;

javax.imageio.ImageIO;

java.io.*;

 

二、為什么要將BufferedImage轉為byte數組

 

在傳輸中，圖片是不能直接傳的，因此需要把圖片變為字節數組，然后傳輸比較方便；只需要一般輸出流的write方法即可；

而字節數組變成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image表示獲得的BufferedImage；

參數format表示圖片的格式，比如“gif”等；

參數out表示輸出流，如果要轉成Byte數組，則輸出流為ByteArrayOutputStream即可；

執行完后，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：編寫一個網絡程序，通過Socket將圖片從服務器端傳到客戶端，並存入文件系統；

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);
    }

}

本文摘自：http://blog.csdn.net/xiazdong/article/details/6929975