BufferedImage与byte[]互转

参考：http://blog.csdn.net/xiazdong/article/details/6929975

 

一、需要用到的类

java.awt.image.BufferedImage;

javax.imageio.ImageIO;

java.io.*;

 

二、为什么要将BufferedImage转为byte数组

在传输中，图片是不能直接传的，因此需要把图片变为字节数组，然后传输比较方便；只需要一般输出流的write

方法即可；而字节数组变成BufferedImage能够还原图像。

 

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); 方法可以很好的解决问题；

参数image表示获得的BufferedImage；

参数format表示图片的格式，比如“gif”等；

参数out表示输出流，如果要转成Byte数组，则输出流为ByteArrayOutputStream即可；

执行完后，只需要toByteArray() 就能得到byte[];

 

五、byte[] ------>BufferedImage

ByteArrayInputStream in = new ByteArrayInputStream(byte[]b);    //将b作为输入流；

BufferedImage image = ImageIO.read(InputStream in);     //将in作为输入流，读取图片存入image中，

而这里in可以为ByteArrayInputStream();

 

六、显示BufferedImage

public void paint(Graphics g){

         super.paint(g);

         g.drawImage(image);    //image为BufferedImage类型

}

 

七、实例

 

要求：编写一个网络程序，通过Socket将图片从服务器端传到客户端，并存入文件系统；

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("获取图像");
		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);
	}

}