md5 工具类

package com.xyh.alipay.util;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.codec.digest.DigestUtils;


public class MD5 {

    /** 
     * 方法描述:将字符串MD5加码 生成32位md5码 
     * @param inStr 
     * @return 
     */  
    public static String md5(String inStr) {  
        try {  
            return DigestUtils.md5Hex(inStr.getBytes("UTF-8"));  
        } catch (UnsupportedEncodingException e) {  
            throw new RuntimeException("MD5签名过程中出现错误");  
        }  
    }  
  
    /** 
     * 方法描述:签名字符串 
     * @param params 需要签名的参数 
     * @param appSecret 签名密钥 
     * @return 
     */  
    public static String sign(Map<String, String> params, String appSecret) {  
        StringBuilder valueSb = new StringBuilder();  
        params.put("appSecret", appSecret);  
        // 将参数以参数名的字典升序排序  
        Map<String, String> sortParams = new TreeMap<String, String>(params);  
        Set<Entry<String, String>> entrys = sortParams.entrySet();  
        // 遍历排序的字典,并拼接value1+value2......格式  
        for (Entry<String, String> entry : entrys) {  
            valueSb.append(entry.getValue());  
        }  
        params.remove("appSecret");  
        return md5(valueSb.toString());  
    }  
  
    /** 
     * 方法描述:验证签名 
     * @param appSecret 加密秘钥 
     * @param request 
     * @return 
     * @throws Exception 
     */  
    public static boolean verify(String appSecret, HttpServletRequest request) throws Exception {  
  
        String sign = request.getParameter("sign");  
        if (sign == null) {  
            throw new Exception(URLEncoder.encode("请求中没有带签名", "UTF-8"));  
        }  
        if (request.getParameter("timestamp") == null) {  
            throw new Exception(URLEncoder.encode("请求中没有带时间戳", "UTF-8"));  
        }  
  
        HashMap<String, String> params = new HashMap<String, String>();  
  
        // 获取url参数  
        @SuppressWarnings("unchecked")  
        Enumeration<String> enu = request.getParameterNames();  
        while (enu.hasMoreElements()) {  
            String paramName = enu.nextElement().trim();  
            if (!paramName.equals("sign")) {  
                // 拼接参数值字符串并进行utf-8解码，防止中文乱码产生  
                params.put(paramName, URLDecoder.decode(request.getParameter(paramName), "UTF-8"));  
            }  
        }  
  
        params.put("appSecret", appSecret);  
  
        // 将参数以参数名的字典升序排序  
        Map<String, String> sortParams = new TreeMap<String, String>(params);  
        Set<Entry<String, String>> entrys = sortParams.entrySet();  
  
        // 遍历排序的字典,并拼接value1+value2......格式  
        StringBuilder valueSb = new StringBuilder();  
        for (Entry<String, String> entry : entrys) {  
            valueSb.append(entry.getValue());  
        }  
  
        String mysign = md5(valueSb.toString());  
        if (mysign.equals(sign)) {  
            return true;  
        } else {  
            return false;  
        }  
  
    }  

}