java传输json数据用md5加密过程

1.加密过程：客户端传输数据，包含两部分，一部分原始数据，一部分签名。签名就是对原始数据MD5加密后的字节序列。而原始数据就是普通的string字符串。

2.服务器端呢：将收到的原始数据，进行MD5加密后得到字节序列，将这个字节序列与传输过来的sign的value，进行对比。如果俩sign值一样，则数据没有被破坏。认证加密成功。

3.进行操作MD5,java sdk已经内置支持了，有java.security包，其中的MessageDiggest类。

客户端加密代码如下：

public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		APPMain appMain = new APPMain();
		URL url = new URL(urlString);
		JSONObject returnJson;
		try {
			returnJson = appMain.getResponse(url);
			System.out.println(JSONObject.toJSONString(returnJson));
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

	public JSONObject getResponse(URL url) throws IOException, NoSuchAlgorithmException {
		//��������
		httpURLConnection = (HttpURLConnection) url.openConnection();
		httpURLConnection.setRequestMethod("POST");
		httpURLConnection.setDoOutput(true);
		httpURLConnection.setDoInput(true);
		httpURLConnection.setUseCaches(false);
		httpURLConnection.setRequestProperty("Content-type", "application/json");
		httpURLConnection.connect();

		//post��������
		OutputStream outStrm = httpURLConnection.getOutputStream();
		DataOutputStream objOutputStrm = new DataOutputStream(outStrm);
		JSONObject obj = new JSONObject();
		JSONObject commentJson = new JSONObject();
		commentJson.put("phone", "13823135363");
        obj.put("param", commentJson);
        obj.put("ts", "abc");
        obj.put("mn", "abc");
        obj.put("imei", "abc");
        obj.put("version", "abc");
        obj.put("token", "abc");
        StringBuilder sBuilder = new StringBuilder();
        createBeforeEncryptString(sBuilder,"ts","abc","&");
        createBeforeEncryptString(sBuilder,"mn","abc","&");
        createBeforeEncryptString(sBuilder,"imei","abc","&");
        createBeforeEncryptString(sBuilder,"version","abc","&");
        createBeforeEncryptString(sBuilder,"token","abc","&");
        createBeforeEncryptString(sBuilder,"param",commentJson.toJSONString(),"");
        String encrapted = sBuilder.toString();
        obj.put("sign", md5Encrypt(encrapted));
        objOutputStrm.writeBytes(obj.toString());
        objOutputStrm.flush();
        objOutputStrm.close();

        //input
        BufferedReader reader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
        String lines =reader.readLine();//��ȡ������
        JSONObject inputJson=JSONObject.parseObject(lines);
        reader.close();  

        System.out.println(md5Encrypt(encrapted));
		return inputJson;
	}
	public String md5Encrypt(String content) {

		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update( content.getBytes() );
	        return getHashString( md );
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}
	 public String getHashString( MessageDigest digest )
	    {
	        StringBuilder builder = new StringBuilder();
	        for ( byte b : digest.digest() )
	        {
	            builder.append( Integer.toHexString( (b >> 4) & 0xf ) );
	            builder.append( Integer.toHexString( b & 0xf ) );
	        }
	        return builder.toString();
	    }
	 public void createBeforeEncryptString(StringBuilder sb,String key,String value,String gap) {
		sb.append(key).append("=").append(value).append(gap);
	}
}

服务器端代码如下：

@Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        BodyReaderHttpServletRequestWrapper requestWrapper = null;
        if (request instanceof HttpServletRequest) {
            requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
        }

        String body = requestWrapper.getBody();

        if(!StringUtils.isEmpty(body)){
            ParamIn param = JSONObject.parseObject(body, ParamIn.class);
            StringBuilder _sb = new StringBuilder();
            _sb.append("ts").append("=").append(param.getTs()).append("&");
            _sb.append("mn").append("=").append(param.getMn()).append("&");
            _sb.append("imei").append("=").append(param.getImei()).append("&");
            _sb.append("version").append("=").append(param.getVersion()).append("&");
            _sb.append("token").append("=").append(param.getToken());

            if(!StringUtils.isEmpty(param.getParam())){
                _sb.append("&").append("param").append("=").append(param.getParam());
            }

            logger.info("to be encrypted: " + _sb.toString());

            String md5Encrypted = HashEncoder.encode(HashAlgorithm.MD5, _sb.toString());

            logger.info("encrypted: " + md5Encrypted);
            if(!md5Encrypted.equalsIgnoreCase(param.getSign())){
                logger.info("sign invalid");
                this.response(response, JSONObject.toJSONString(new ResultObject(ResultCode.SIGN_INVALID)));
                return;
            }else{
                logger.info("valid sign success");
            }

        }else{
            this.response(response, JSONObject.toJSONString(new ResultObject(ResultCode.NULL_PARAM)));
            return;
        }

        //签名验证成功
        chain.doFilter(requestWrapper, response);
    }