ublic class SignatureHelper_return { public static String sign(Map params, String privateKey) { Properties properties = new Properties(); for (Iterator iter = params.keySet().iterator(); iter.hasNext();) { String name = (String) iter.next(); Object value = params.get(name); if (name == null || name.equalsIgnoreCase("sign") || name.equalsIgnoreCase("sign_type")) { continue; } properties.setProperty(name, value.toString()); } String content = getSignatureContent(properties); return sign(content, privateKey); } public static String getSignatureContent(Properties properties) { StringBuffer content = new StringBuffer(); List keys = new ArrayList(properties.keySet()); Collections.sort(keys); for (int i = 0; i < keys.size(); i++) { String key = (String) keys.get(i); String value = properties.getProperty(key); content.append((i == 0 ? "" : "&") + key + "=" + value); } return content.toString(); } public static String sign(String content, String privateKey) { if (privateKey == null) { return null; } String signBefore = content + privateKey; //System.out.print("signBefore=" + signBefore); return Md5Encrypt.md5(signBefore); } }