Java 微信签名MD5加密或HMACSHA256加密 工具类

java微信加密签名的工具类
代码如下:

import java.net.InetAddress;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

public class Util {
	
	  //获取终端Ip
	  public static String GetIp() {
	      InetAddress ia = null;
	      try {
	          ia = InetAddress.getLocalHost();
	          String localip = ia.getHostAddress();
	          return localip;
	      } catch (Exception e) {
	          return null;
	      }
	  }
	
	/**  
     *  
     * 方法用途: 对所有传入参数按照字段名的 ASCII 码从小到大排序（字典序），并且生成url参数串
  
     * 实现步骤: 
  
     *  
     * @param paraMap   要排序的Map对象  
     * @param urlEncode   是否需要URLENCODE  
     * @param keyToLower    是否需要将Key转换为全小写  
     *            true:key转化成小写，false:不转化  
     * @return  
     */  
    public static String formatUrlMap(Map<String, String> paraMap, boolean urlEncode, boolean keyToLower)  
    {  
        if(paraMap == null){  
            return "";  
        }  
        String buff = "";  
        Map<String, String> tmpMap = paraMap;  
        try  
        {  
            List<Map.Entry<String, String>> infoIds = new ArrayList<Map.Entry<String, String>>(tmpMap.entrySet());  
            // 对所有传入参数按照字段名的 ASCII 码从小到大排序（字典序）  
            Collections.sort(infoIds, new Comparator<Map.Entry<String, String>>()  
            {  
                @Override  
                public int compare(Map.Entry<String, String> o1, Map.Entry<String, String> o2)  
                {  
                    return (o1.getKey()).toString().compareTo(o2.getKey());  
                }  
            });  
            // 构造URL 键值对的格式  
            StringBuilder buf = new StringBuilder();  
            for (Map.Entry<String, String> item : infoIds)  
            {  
                    String key = item.getKey();  
                    String val = item.getValue();  
                    if (urlEncode)  
                    {  
                        val = URLEncoder.encode(val, "utf-8");  
                    }  
                    if (keyToLower)  
                    {  
                        buf.append(key.toLowerCase() + "=" + val);  
                    } else  
                    {  
                        buf.append(key + "=" + val);  
                    }  
                    buf.append("&");  
            }  
            buff = buf.toString();  
            if (buff.isEmpty() == false)  
            {  
                buff = buff.substring(0, buff.length() - 1);  
            }  
        } catch (Exception e)  
        {  
            return null;  
        }  
        return buff;  
    }  

    /**
     * 生成签名. 注意，若含有sign_type字段，必须和signType参数保持一致。
     * 参数值为空，则不参与签名
     * @param data 待签名数据
     * @param key API密钥
     * @param signType 签名方式
     * @return 签名
     */
    public static String generateSignature(final Map<String, String> data, String key, String signType) throws Exception {
        Set<String> keySet = data.keySet();
        String[] keyArray = keySet.toArray(new String[keySet.size()]);
        Arrays.sort(keyArray);
        StringBuilder sb = new StringBuilder();
        for (String k : keyArray) {
            if (k.equals("sign")) {
                continue;
            }
            if (data.get(k).trim().length() > 0) // 参数值为空，则不参与签名
                sb.append(k).append("=").append(data.get(k).trim()).append("&");
        }
        sb.append("key=").append(key);
        if ("MD5".equals(signType)) {
            return MD5(sb.toString()).toUpperCase();
        }
        else if ("HMACSHA256".equals(signType)) {
            return HMACSHA256(sb.toString(), key);
        }
        else {
            throw new Exception(String.format("Invalid sign_type: %s", signType));
        }
    }
    
    /**
     * MD5签名默认
     * @param data
     * @param key
     * @return
     * @throws RuntimeException
     */
    public static String sign(Map<String, String> data , String key) {
    	try {
			return generateSignature(data , key , "MD5");
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e.getMessage());
		}
    }
    
    /**
     * 生成 MD5
     *
     * @param data 待处理数据
     * @return MD5结果
     */
    public static String MD5(String data) throws Exception {
        java.security.MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] array = md.digest(data.getBytes("UTF-8"));
        StringBuilder sb = new StringBuilder();
        for (byte item : array) {
            sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
        }
        return sb.toString().toUpperCase();
    }

    /**
     * 生成 HMACSHA256
     * @param data 待处理数据
     * @param key 密钥
     * @return 加密结果
     * @throws Exception
     */
    public static String HMACSHA256(String data, String key) throws Exception {
        Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
        SecretKeySpec secret_key = new SecretKeySpec(key.getBytes("UTF-8"), "HmacSHA256");
        sha256_HMAC.init(secret_key);
        byte[] array = sha256_HMAC.doFinal(data.getBytes("UTF-8"));
        StringBuilder sb = new StringBuilder();
        for (byte item : array) {
            sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
        }
        return sb.toString().toUpperCase();
    }

}

若哪有不足,请大家多多指导!!