package com.io.img;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import javax.imageio.stream.FileImageInputStream;
import javax.imageio.stream.FileImageOutputStream;
/**
 * 将文件 转换成byte数组
 * 
 * @author Administrator
 * 
 */
public class ImageByte {
	public static byte[] imageByte(String path) {
		// 定义byte数组
		byte[] data = null;
		ByteArrayOutputStream output = null;
		// 定义fileimage输入流
		FileImageInputStream input = null;
		try {
			input = new FileImageInputStream(new File(path));
			// 获取byte输出流
			output = new ByteArrayOutputStream();
			byte[] buf = new byte[1024];
			int numBytesRead = 0;
			// 读取数据
			while ((numBytesRead = input.read(buf)) != -1) {
				output.write(buf, 0, numBytesRead);
			}
			// 转换byte数组
			data = output.toByteArray();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (output != null)
				try {
					output.close();
				} catch (IOException e1) {
					e1.printStackTrace();
				}
			if (input != null)
				try {
					input.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
		}
		return data;
	}
	
	
	/**
	 *  将byte数组转换为img
	 */
	public  static void byteImage(byte[] data,String path){
		FileImageOutputStream imageOutput=null;
		try{
			//获取文件图片输出流
			imageOutput = new FileImageOutputStream(new File(path));
			//输出图片
			imageOutput.write(data, 0, data.length);
			System.out.println("图片存到了了" + path);
		} catch(Exception ex) {
			ex.printStackTrace();
		}finally{
			if(imageOutput!=null){
				try {
					imageOutput.close();
				} catch (IOException e) {
					e.printStackTrace();
				}	
			}
		}
	}
	
	public static void main(String[] args) {
		String path = "E:\\my.png";
		byte img[]=imageByte(path);
		System.out.println(img);
		byteImage(img, "F://test.png");
	}
}原文:http://blog.csdn.net/itlqi/article/details/44967191