package com.changyu.foryou.tools;

import java.io.IOException;

import java.security.GeneralSecurityException;

import java.security.Key;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import java.util.TreeMap;

import javax.crypto.KeyGenerator;

/***

*

* @author xiaowei

*coryright @ xiaowei

*/

public class Sign {

/**

* 签名生成算法

*

* @param params 请求参数集，所有参数必须已转换为字符串类型

* @param params secret 签名密钥

* @return 签名

* @throws IOException

*/

public static String getSignature(HashMap<String, String[]> params) throws IOException {

String[] secret = params.get("secret");

// 先将参数以其参数名的字典序升序进行排序

Map<String, String[]> sortedParams = new TreeMap<String, String[]>(params);

Set<Entry<String, String[]>> entrys = sortedParams.entrySet();

// 遍历排序后的字典，将所有参数按"key=value"格式拼接在一起

StringBuilder basestring = new StringBuilder();

for (Entry<String, String[]> param : entrys) {

if (param.getKey().equals("timestamp") || param.getKey().equals("secret") || param.getKey().equals("sign")) {

continue;

}

String value = ((String[]) param.getValue())[0];

basestring.append(param.getKey()).append("=").append(value);

}

basestring.append(secret[0]);

// 使用MD5对待签名串求签

byte[] bytes;

try {

MessageDigest md5 = MessageDigest.getInstance("MD5");

bytes = md5.digest(basestring.toString().getBytes("UTF-8"));

System.out.println(basestring.toString()); //一次

} catch (GeneralSecurityException ex) {

throw new IOException(ex);

}

// 将MD5输出的二进制结果转换为小写的十六进制

StringBuilder sign = new StringBuilder();

for (int i = 0; i < bytes.length; i++) {

String hex = Integer.toHexString(bytes[i] & 0xFF);

if (hex.length() == 1) {

sign.append("0");

}

sign.append(hex);

}

return sign.toString();

}

public static byte[] createPrivateKey() {

byte[] privateKey = null;

try {

KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");

keyGenerator.init(168); //选择DESede算法,密钥长度为112位或168位

Key myKey = keyGenerator.generateKey(); //生成密钥

privateKey = myKey.getEncoded();

} catch (NoSuchAlgorithmException e) {

e.printStackTrace();

}

return privateKey;

}

}