Authentication

package com.achpay.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;

public class Utils {

    // private static final Logger logger = LoggerFactory.getLogger(Utils.class);

    public static void main(String[] args) {

        String key="[email protected]#";

        Map map =new HashMap();
        map.put("merchantCode","ME1657708812740");
        map.put("unionId","9746630509196001");
        map.put("crypto","24353");


        System.out.println("========== sign =================: "+getSign(map,key));

    }


    /**
     * sign=MD5(accountAttr=accountAttr&accountName=accountName&accountNo=accountNo&amount=amount&bankName=bankName&bankNumber=bankNumber&city=city&mchId=mchId&mchOrderNo=mchOrderNo¬ifyUrl=notifyUrl&province=province&remark=remark&reqTime=reqTime&key=key).toUpperCase()
     * @param params
     * @param privatekey
     * @return
     */
    public static String getSign(Map<String, Object> params, String privatekey) {

        MapRemoveNullUtil.removeNullEntry(params);

        Map<String, Object> map = new TreeMap<>();
        map.putAll(params);
        //以key1 = value1&key2 = value2
        StringBuilder stringBuilder = new StringBuilder();
        for (Map.Entry<String, Object> s : map.entrySet()) {
            String key = s.getKey();
            Object value = s.getValue();
            stringBuilder.append(key).append("=").append(value).append("&");
        }
        stringBuilder.append("key="+privatekey);

        // logger.info("getSign{}", stringBuilder.toString());
        String sign = MD5Util.getMd5(stringBuilder.toString().getBytes()).toUpperCase();
        // logger.info("getSign-stringBuilder-sign为: {}, {}",stringBuilder, sign);
        return sign;
    }




    /**
     * @param obj
     * @return
     * @throws Exception
     */
    public static Map<String, Object> objectToMap(Object obj) throws Exception {
        if(obj == null)
            return null;

        Map<String, Object> map = new HashMap<String, Object>();

        BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
        PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
        for (PropertyDescriptor property : propertyDescriptors) {
            String key = property.getName();
            if (key.compareToIgnoreCase("class") == 0) {
                continue;
            }
            Method getter = property.getReadMethod();
            Object value = getter!=null ? getter.invoke(obj) : null;
            map.put(key, value);
        }

        return map;
    }



    /**
     * @param map
     */
    public static void removeNullEntry(Map map){
        removeNullKey(map);
        removeNullValue(map);
    }

    /**
     * @param map
     * @return
     */
    public static void removeNullKey(Map map){
        Set set = map.keySet();
        for (Iterator iterator = set.iterator(); iterator.hasNext();) {
            Object obj = (Object) iterator.next();
            remove(obj, iterator);
        }
    }


    /**
     * @param map
     * @return
     */
    public static void removeNullValue(Map map){
        Set set = map.keySet();
        for (Iterator iterator = set.iterator(); iterator.hasNext();) {
            Object obj = (Object) iterator.next();
            Object value =(Object)map.get(obj);
            remove(value, iterator);
        }
    }

    /**
     * @param obj
     * @param iterator
     */
    private static void remove(Object obj,Iterator iterator){

        if(obj instanceof String){
            String str = (String)obj;
            if(isEmpty(str.trim())){ //output map：{2=BB, 1=AA, 5=CC}
                iterator.remove();
            }
        }else if(obj instanceof Collection){
            Collection col = (Collection)obj;
            if(col==null||col.isEmpty()){
                iterator.remove();
            }
        }else if(obj instanceof Map){
            Map temp = (Map)obj;
            if(temp==null||temp.isEmpty()){
                iterator.remove();
            }
        }else if(obj instanceof Object[]){
            Object[] array =(Object[])obj;
            if(array==null||array.length<=0){
                iterator.remove();
            }
        }else{
            if(obj==null){
                iterator.remove();
            }
        }
    }
    public static boolean isEmpty(Object obj){
        return obj == null || obj.toString().length() == 0  || obj.equals("null");
    }


    /**
     */
    public static String getMd5(byte[] bytes) {
        byte abyte0[];
        MessageDigest messagedigest;
        try {
            messagedigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException nosuchalgorithmexception) {
            throw new IllegalArgumentException("no md5 support");
        }
        messagedigest.update(bytes);
        abyte0 = messagedigest.digest();
        return byte2hex(abyte0);

    }

    /**
     */
    public static String byte2hex(byte bytes[]) {
        StringBuffer stringBuffer = new StringBuffer(bytes.length * 2);
        for (int i = 0; i < bytes.length; i++) {
            if ((bytes[i] & 0xff) < 16) {
                stringBuffer.append("0");
            }
            stringBuffer.append(Long.toString((long) bytes[i] & (long) 255, 16));
        }

        return stringBuffer.toString().toUpperCase();
    }

}