Java 图片与byte数组互相转换

 //图片到byte数组
   public byte[] image2byte(String path){
     byte[] data = null;
     FileImageInputStream input = null;
     try {
       input = new FileImageInputStream(new File(path));
       ByteArrayOutputStream output = new ByteArrayOutputStream();
       byte[] buf = new byte[1024];
       int numBytesRead = 0;
       while ((numBytesRead = input.read(buf)) != -1) {
       output.write(buf, 0, numBytesRead);
       }
       data = output.toByteArray();
       output.close();
       input.close();
     }
     catch (FileNotFoundException ex1) {
       ex1.printStackTrace();
     }
     catch (IOException ex1) {
       ex1.printStackTrace();
     }
     return data;
   }

   //byte数组到图片
   public void byte2image(byte[] data,String path){
     if(data.length<3||path.equals("")) return;
     try{
     FileImageOutputStream imageOutput = new FileImageOutputStream(new File(path));
     imageOutput.write(data, 0, data.length);
     imageOutput.close();
     System.out.println("Make Picture success,Please find image in " + path);
     } catch(Exception ex) {
       System.out.println("Exception: " + ex);
       ex.printStackTrace();
     }
   }
   //byte数组到16进制字符串
   public String byte2string(byte[] data){
     if(data==null||data.length<=1) return "0x";
     if(data.length>200000) return "0x";
     StringBuffer sb = new StringBuffer();
     int buf[] = new int[data.length];
     //byte数组转化成十进制
     for(int k=0;k<data.length;k++){
       buf[k] = data[k]<0?(data[k]+256):(data[k]);
     }
     //十进制转化成十六进制
     for(int k=0;k<buf.length;k++){
       if(buf[k]<16) sb.append("0"+Integer.toHexString(buf[k]));
       else sb.append(Integer.toHexString(buf[k]));
     }
     return "0x"+sb.toString().toUpperCase();
   } 

文件解析：
FileImageOutputStream 换成了 FileOutputStream
FileImageInputStream 换成 FileInputStream

转自：http://blog.csdn.net/huang9012/article/details/18241539/