①1、16进制字符串 转 byte[]

public static byte[] hexStringToBytes(String hexString) {   
		   if (hexString == null || hexString.equals("")) {   
		       return null;   
		    }   
		    hexString = hexString.toUpperCase();   
		    int length = hexString.length() / 2;   
		    char[] hexChars = hexString.toCharArray();   
		   byte[] d = new byte[length];   
		    for (int i = 0; i < length; i++) {   
		        int pos = i * 2;   
		      d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));   
		    }   
		    return d;   
         }   
	private static byte charToByte(char c) {   
		    return (byte) "0123456789ABCDEF".indexOf(c);   
	}  

2、byte[] 转 图片/xml/ pdf

 public static void byteTofile(byte[] data,String path){
		    if(data.length<3||path.equals("")) return;
		    try{
		    FileOutputStream imageOutput = new FileOutputStream(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) {
		    	log.info("byteTofile.Exception():" + ex);
		      ex.printStackTrace();
		    }
		  }

测试16进制字符串 转 byte[] 转文件

String s1="52abcdef5252";
byte[] stringHex = hexStringToBytes(s1);
		byteTofile(stringHex, "E:\\wangyc.png");

②3、图片 xml pdf 转byte[]

public static byte[] fileTobyte(String path){
		    byte[] data = null;
		    FileInputStream input = null;
		    try {
		      input = new FileInputStream(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();
		      log.info("fileTobyte.FileNotFoundException():"+ex1);
		    }
		    catch (IOException ex1) {
		      ex1.printStackTrace();
		      log.info("fileTobyte.IOException():"+ex1);
		    }
		    return data;
		  }
	

4、byte[] 转16进制字符串

public static String bytesToHexString(byte[] src){  
	    StringBuilder stringBuilder = new StringBuilder("");  
	    if (src == null || src.length <= 0) {  
	        return null;  
	    }  
	    for (int i = 0; i < src.length; i++) {  
	        int v = src[i] & 0xFF;  
	        String hv = Integer.toHexString(v);  
	        if (hv.length() < 2) {  
	            stringBuilder.append(0);  
	        }  
	        stringBuilder.append(hv);  
	    }  
	    return stringBuilder.toString();  
	}  

测试文件 转byte[] 转16进制字符串

byte[] image2byte = fileTobyte("E:\\wangyc.png");
String bytesToHexString = bytesToHexString(image2byte);
System.out.println("bytesToHexString:"+bytesToHexString);

5、③

网络文件 转byte[]

public static byte[] getFileFromNetByUrl(String strUrl){    
	        try {    
	            URL url = new URL(strUrl);    
	            HttpURLConnection conn = (HttpURLConnection)url.openConnection();    
	            conn.setRequestMethod("GET");    
	            conn.setConnectTimeout(5 * 1000);    
	            InputStream inStream = conn.getInputStream();//通过输入流获取图片数据    
	            byte[] btImg = readInputStream(inStream);//得到图片的二进制数据    
	            return btImg;    
	        } catch (Exception e) {    
	            e.printStackTrace();    
	        }    
	        return null;    
	    }

 public static byte[] readInputStream(InputStream inStream) throws Exception{    	        ByteArrayOutputStream outStream = new ByteArrayOutputStream();    
	        byte[] buffer = new byte[1024];    
	        int len = 0;    
	        while( (len=inStream.read(buffer)) != -1 ){    
	            outStream.write(buffer, 0, len);    
	        }    
	        inStream.close();    
	        return outStream.toByteArray();    
	    } 

测试网络文件转byte[]　再转１６进制字符串

byte[] image2byte = getFileFromNetByUrl("http://oss-cn-shenzhen.aliyuncs.com/1502694718995.xml");
String bytesToHexString = bytesToHexString(image2byte);
System.out.println("bytesToHexString:"+bytesToHexString);