md5校验

public void () throws Exception{
		byte[] by = Files.readAllBytes(Paths.get("E:","Dog.java"));
		MessageDigest md =  MessageDigest.getInstance("SHA-256");
		md.update(by);
		byte[] digest = md.digest();

		StringBuilder sb = new StringBuilder();
		for(byte b:digest){
			String hexString = Integer.toHexString(b);
			sb.append(hexString);
		}
		System.out.println(sb);

	}

public void ComplexMd5(){
		MessageDigest md  = null;
		try {
			 md  = MessageDigest.getInstance("SHA-256");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		try(FileInputStream fi = new FileInputStream("E:/Dog.java");
				) {
			byte[] arr = new byte[4];
			int len = -1;
			while((len=fi.read(arr))>0){
				md.update(arr,0,len);
				//System.out.println(new String(arr,0,len));
			}

			byte[] digest = md.digest();

			StringBuilder sb = new StringBuilder();
			for(byte by:digest){
				String hs = Integer.toHexString(by);
				sb.append(hs);
			}
			System.out.println(sb);


		} catch (Exception e) {
			e.printStackTrace();
		}		
	}