Java实现微信支付的签名算法示例

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.ObjectUtils;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;
/**
 * @author Wen先森
 * @version 1.0
 * @date 2022/8/25 11:07
 */
@Slf4j
public class SignatureUntils {
    public static final String  KEY="0de034fa56cf0ce676570d571de2705b";
    /**
     * 处理要签名的数据
     * 1. 获取参数content,content为json字符串
     * 2. 转换参数成URL 键值对的格式（即 key1=value1&key2=value2…）
     * 3. 返回整理好的待签名数据
     */
    private static String handleStr(Map<String,?> paramsMap){
        //转成map
        //获取参数名称转成List集合
        Set<String> keySet = paramsMap.keySet();
        List<String> paramNames = new ArrayList<String>(keySet);
        //对参数名称进行排序
        Collections.sort(paramNames);
        //把参数转化成url键值对格式并返回
        StringBuilder paramNameValue = new StringBuilder();
        for (String paramName : paramNames ) {
            if("sign".equals(paramName) || ObjectUtils.isEmpty(paramsMap.get(paramName))) {
                continue;
            }else{
                paramNameValue.append(paramName).append("=").append(paramsMap.get(paramName)).append("&");
            }
        }
       // paramNameValue.deleteCharAt(paramNameValue.length()-1);
        return paramNameValue.toString();
    }
    /**
     * 生成签名；
     *
     * @param params
     * @return
     */
    static public String signForInspiry(Map<String,?> params, String key) {
        //先排序
        String str = handleStr(params);
        StringBuffer sbkey = new StringBuffer(str);
        sbkey = sbkey.append("key=" + key);
        //MD5加密,结果转换为大写字符
        String sign = toMd5(sbkey.toString()).toUpperCase();
        return sign;
    }
    /**
     * 对字符串进行MD5加密
     *
     * @param str 需要加密的字符串
     * @return 小写MD5字符串 32位
     */
    public static String toMd5(String str) {
        String re = null;
        byte encrypt[];
        try {
            byte[] tem = str.getBytes();
            MessageDigest md5 = MessageDigest.getInstance("md5");
            md5.reset();
            md5.update(tem);
            encrypt = md5.digest();
            StringBuilder sb = new StringBuilder();
            for (byte t : encrypt) {
                String s = Integer.toHexString(t & 0xFF);
                if (s.length() == 1) {
                    s = "0" + s;
                }
                sb.append(s);
            }
            re = sb.toString();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return re;
    }
    public static boolean checkSign(String sign,Map<String,?> params,String key){
        try {
            String signValue = signForInspiry(params, key);
            if (StringUtils.endsWithIgnoreCase(signValue,sign)){
                log.info("验签成功");
                return true;
            }
        } catch (Exception e) {
            log.info("验签异常");
            e.printStackTrace();
        }
        log.info("验签失败");
        return false;
    }
    public static void main(String[] args) {
        String sign="81AA2B818EAD40FE2D8E7E3242C14577";
        String key="0de034fa56cf0ce676570d571de2705b";
        Map<String,Object> map = new HashMap<>();
        map.put("deviceSn","000SD50030180000001");
        map.put("timestamp","1661759090226");
        map.put("sign",sign);
        map.put("orderNo","HMP2208310000584428263559179");
        // 需要签名参数
        System.out.println("签名参数:"+map);
        String sortPram = handleStr(map);
        // 排序后和去掉sign参数之后
        System.out.println("排序后参数:"+sortPram);
        String signValue = signForInspiry(map, "0de034fa56cf0ce676570d571de2705b");
        // MD5加密并全部大写
        System.out.println("签名内容:"+signValue);
        // 验签
        checkSign(sign, map, key);
    }
}