对接API接口的时候往往为了安全考虑，需要实现数据签名和验签，最常用的就是使用公私钥对进行签名验签，主要流程为：
1、生成公私钥对
2、使用私钥进行签名
3、使用公钥验证签名
这么最的主要目的是为了保证请求来源的合法性，参数的正确性（不被篡改）
废话不多说，直接撸出工具类，本次工具类一共3个。Rsa.java、Base64.java、BaseHelper.java。生成签名的时候将需要传递的参数bean通过BaseHelper.sortParamAll(bean)转成K=V&K1=V1......的形式，然后调用Rsa.sign()方法即可生成签名。
验签的时候获取到传递过来的参数json串（jsonParams），同样将业务参数通过BaseHelper.sortCheckParam(jsonParams)转成K=V&K1=V1......的形式（剔除sign参数），然后调用Rsa.doCheck()方法验证签名是否通过。
传递参数示例：
{ "name": "zhangsan", "age": "34", "amont": "100.00", "sign": "bpy8NrCnRq8lK9wVWI0EHNJVUgEpJFWlwOIIvMOUYfflQsvRzw8gCFNLpT/0pTOHeHwB/Cn8tMmXCzv9fnm8cUXlAAofsRYOneVseGt+ArgtsXGitjACA0L3Krbn2SsG+xEL/VbMGW2UwyLHx8FNz88ZzbORSKaERPC7tL3MWpQ=", "time": "20170831103259" }
package cn.test; import java.security.KeyFactory; import java.security.PrivateKey; import java.security.PublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; /** * RSA工具类 * */ public class Rsa { public static final String SIGN_ALGORITHMS = "MD5WithRSA"; /** * @param content:签名的参数内容 * @param privateKey：私钥 * @return */ public static String sign(String content, String privateKey) { String charset = "utf-8"; try { PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(Base64.decode(privateKey)); KeyFactory keyf = KeyFactory.getInstance("RSA"); PrivateKey priKey = keyf.generatePrivate(priPKCS8); java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS); signature.initSign(priKey); signature.update(content.getBytes(charset)); byte[] signed = signature.sign(); return Base64.encode(signed); } catch (Exception e) { e.printStackTrace(); } return null; } /** * @param content：验证参数的内容 * @param sign：签名 * @param publicKey：公钥 * @return */ public static boolean doCheck(String content, String sign, String publicKey) { try { KeyFactory keyFactory = KeyFactory.getInstance("RSA"); byte[] encodedKey = Base64.decode(publicKey); PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey)); java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS); signature.initVerify(pubKey); signature.update(content.getBytes("utf-8")); boolean bverify = signature.verify(Base64.decode(sign)); return bverify; } catch (Exception e) { e.printStackTrace(); } return false; } }
package cn.test; /** * Base64 工具类 * */ public final class Base64 { static private final int BASELENGTH = 128; static private final int LOOKUPLENGTH = 64; static private final int TWENTYFOURBITGROUP = 24; static private final int EIGHTBIT = 8; static private final int SIXTEENBIT = 16; static private final int FOURBYTE = 4; static private final int SIGN = -128; static private final char PAD = '='; static private final boolean fDebug = false; static final private byte[] base64Alphabet = new byte[BASELENGTH]; static final private char[] lookUpBase64Alphabet = new char[LOOKUPLENGTH]; static { for (int i = 0; i < BASELENGTH; ++i) { base64Alphabet[i] = -1; } for (int i = 'Z'; i >= 'A'; i--) { base64Alphabet[i] = (byte) (i - 'A'); } for (int i = 'z'; i >= 'a'; i--) { base64Alphabet[i] = (byte) (i - 'a' + 26); } for (int i = '9'; i >= '0'; i--) { base64Alphabet[i] = (byte) (i - '0' + 52); } base64Alphabet['+'] = 62; base64Alphabet['/'] = 63; for (int i = 0; i <= 25; i++) { lookUpBase64Alphabet[i] = (char) ('A' + i); } for (int i = 26, j = 0; i <= 51; i++, j++) { lookUpBase64Alphabet[i] = (char) ('a' + j); } for (int i = 52, j = 0; i <= 61; i++, j++) { lookUpBase64Alphabet[i] = (char) ('0' + j); } lookUpBase64Alphabet[62] = (char) '+'; lookUpBase64Alphabet[63] = (char) '/'; } private static boolean isWhiteSpace(char octect) { return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9); } private static boolean isPad(char octect) { return (octect == PAD); } private static boolean isData(char octect) { return (octect < BASELENGTH && base64Alphabet[octect] != -1); } /** * Encodes hex octects into Base64 * * @param binaryData * Array containing binaryData * @return Encoded Base64 array */ public static String encode(byte[] binaryData) { if (binaryData == null) { return null; } int lengthDataBits = binaryData.length * EIGHTBIT; if (lengthDataBits == 0) { return ""; } int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP; int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP; int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1 : numberTriplets; char encodedData[] = null; encodedData = new char[numberQuartet * 4]; byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0; int encodedIndex = 0; int dataIndex = 0; if (fDebug) { System.out.println("number of triplets = " + numberTriplets); } for (int i = 0; i < numberTriplets; i++) { b1 = binaryData[dataIndex++]; b2 = binaryData[dataIndex++]; b3 = binaryData[dataIndex++]; if (fDebug) { System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3); } l = (byte) (b2 & 0x0f); k = (byte) (b1 & 0x03); byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc); if (fDebug) { System.out.println("val2 = " + val2); System.out.println("k4 = " + (k << 4)); System.out.println("vak = " + (val2 | (k << 4))); } encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)]; encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3]; encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f]; } // form integral number of 6-bit groups if (fewerThan24bits == EIGHTBIT) { b1 = binaryData[dataIndex]; k = (byte) (b1 & 0x03); if (fDebug) { System.out.println("b1=" + b1); System.out.println("b1<<2 = " + (b1 >> 2)); } byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; encodedData[encodedIndex++] = lookUpBase64Alphabet[k << 4]; encodedData[encodedIndex++] = PAD; encodedData[encodedIndex++] = PAD; } else if (fewerThan24bits == SIXTEENBIT) { b1 = binaryData[dataIndex]; b2 = binaryData[dataIndex + 1]; l = (byte) (b2 & 0x0f); k = (byte) (b1 & 0x03); byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); encodedData[encodedIndex++] = lookUpBase64Alphabet[val1]; encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)]; encodedData[encodedIndex++] = lookUpBase64Alphabet[l << 2]; encodedData[encodedIndex++] = PAD; } return new String(encodedData); } /** * Decodes Base64 data into octects * * @param encoded * string containing Base64 data * @return Array containind decoded data. */ public static byte[] decode(String encoded) { if (encoded == null) { return null; } char[] base64Data = encoded.toCharArray(); // remove white spaces int len = removeWhiteSpace(base64Data); if (len % FOURBYTE != 0) { return null;// should be divisible by four } int numberQuadruple = (len / FOURBYTE); if (numberQuadruple == 0) { return new byte[0]; } byte decodedData[] = null; byte b1 = 0, b2 = 0, b3 = 0, b4 = 0; char d1 = 0, d2 = 0, d3 = 0, d4 = 0; int i = 0; int encodedIndex = 0; int dataIndex = 0; decodedData = new byte[(numberQuadruple) * 3]; for (; i < numberQuadruple - 1; i++) { if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++])) || !isData((d3 = base64Data[dataIndex++])) || !isData((d4 = base64Data[dataIndex++]))) { return null; } // if found "no data" just return null b1 = base64Alphabet[d1]; b2 = base64Alphabet[d2]; b3 = base64Alphabet[d3]; b4 = base64Alphabet[d4]; decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); decodedData[encodedIndex++] = (byte) (b3 << 6 | b4); } if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))) { return null;// if found "no data" just return null } b1 = base64Alphabet[d1]; b2 = base64Alphabet[d2]; d3 = base64Data[dataIndex++]; d4 = base64Data[dataIndex++]; if (!isData((d3)) || !isData((d4))) {// Check if they are PAD characters if (isPad(d3) && isPad(d4)) { if ((b2 & 0xf) != 0)// last 4 bits should be zero { return null; } byte[] tmp = new byte[i * 3 + 1]; System.arraycopy(decodedData, 0, tmp, 0, i * 3); tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4); return tmp; } else if (!isPad(d3) && isPad(d4)) { b3 = base64Alphabet[d3]; if ((b3 & 0x3) != 0)// last 2 bits should be zero { return null; } byte[] tmp = new byte[i * 3 + 2]; System.arraycopy(decodedData, 0, tmp, 0, i * 3); tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); return tmp; } else { return null; } } else { // No PAD e.g 3cQl b3 = base64Alphabet[d3]; b4 = base64Alphabet[d4]; decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4); decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)); decodedData[encodedIndex++] = (byte) (b3 << 6 | b4); } return decodedData; } /** * remove WhiteSpace from MIME containing encoded Base64 data. * * @param data * the byte array of base64 data (with WS) * @return the new length */ private static int removeWhiteSpace(char[] data) { if (data == null) { return 0; } // count characters that's not whitespace int newSize = 0; int len = data.length; for (int i = 0; i < len; i++) { if (!isWhiteSpace(data[i])) { data[newSize++] = data[i]; } } return newSize; } }
package cn.test; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.Comparator; import java.util.HashMap; import java.util.Map; import java.util.TreeMap; import org.apache.log4j.Logger; import org.json.JSONException; import org.json.JSONObject; /** * 工具类 */ public class BaseHelper { private final static Logger log = Logger.getLogger(BaseHelper.class); public static final String PARAM_EQUAL = "="; public static final String PARAM_AND = "&"; public static String toJSONString(Object obj) { JSONObject json = new JSONObject(); try { Map<String, String> map = bean2Parameters(obj); for (Map.Entry<String, String> entry : map.entrySet()) { json.put(entry.getKey(), entry.getValue()); } } catch (JSONException e) { e.printStackTrace(); } return json.toString(); } /** * 对Object进行List<NameValuePair>转换后按key进行升序排序，以key=value&...形式返回 * * @param list * @return */ public static String sortParam(Object order) { Map<String, String> map = bean2Parameters(order); return sortParam(map); } public static String sortParamAll(Object order) { Map<String, String> map = bean2Parameters(order); return sortCheckParam(map); } /** * 对Object进行List<NameValuePair>转换后按key进行升序排序，以key=value&...形式返回 * * @param list * @return */ public static String sortCheckParam(Map<String, String> order) { if (order == null) { return null; } Map<String, String> parameters = new TreeMap<String, String>(new Comparator<String>() { public int compare(String obj1, String obj2) { return obj1.compareToIgnoreCase(obj2); } }); parameters.putAll(order); StringBuffer sb = new StringBuffer(); for (Map.Entry<String, String> entry : parameters.entrySet()) { if (null != entry.getValue() && !"".equals(entry.getValue()) && !entry.getKey().equals("sign")) { sb.append(entry.getKey()); sb.append(PARAM_EQUAL); sb.append(entry.getValue()); sb.append(PARAM_AND); } } String params = sb.toString(); if (sb.toString().endsWith(PARAM_AND)) { params = sb.substring(0, sb.length() - 1); } log.info("待签名串:" + params); return params; } /** * 将bean转换成键值对列表 * * @param bean * @return */ public static Map<String, String> bean2Parameters(Object bean) { if (bean == null) { return null; } Map<String, String> parameters = new HashMap<String, String>(); if (null != parameters) { // 取得bean所有public 方法 Method[] Methods = bean.getClass().getMethods(); for (Method method : Methods) { if (method != null && method.getName().startsWith("get") && !method.getName().startsWith("getClass")) { // 得到属性的类名 String value = ""; // 得到属性值 try { String className = method.getReturnType().getSimpleName(); if (className.equalsIgnoreCase("int")) { int val = 0; try { val = (Integer) method.invoke(bean); } catch (InvocationTargetException e) { e.printStackTrace(); } value = String.valueOf(val); } else if (className.equalsIgnoreCase("String")) { try { value = (String) method.invoke(bean); } catch (InvocationTargetException e) { e.printStackTrace(); } } if (value != null && value != "") { // 添加参数 // 将方法名称转化为id，去除get，将方法首字母改为小写 String param = method.getName().replaceFirst("get", ""); if (param.length() > 0) { String first = String.valueOf(param.charAt(0)).toLowerCase(); param = first + param.substring(1); } parameters.put(param, value); } } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } } } } return parameters; } /** * 对对Object转换后, 以key=value&...形式返回按key进行升序排序，以key=value&...形式返回 * * @param order * @return */ public static String sortParam(Map<String, String> order) { if (null == order) { return null; } Map<String, String> parameters = new TreeMap<String, String>(new Comparator<String>() { public int compare(String obj1, String obj2) { return obj1.compareToIgnoreCase(obj2); } }); parameters.putAll(order); if (null != parameters) { StringBuffer sb = new StringBuffer(); for (Map.Entry<String, String> entry : parameters.entrySet()) { if (null != entry.getValue() && !"".equals(entry.getValue()) && !entry.getKey().equals("id_type") && !entry.getKey().equals("id_no") && !entry.getKey().equals("acct_name") && !entry.getKey().equals("flag_modify") && !entry.getKey().equals("user_id") && !entry.getKey().equals("no_agree") && !entry.getKey().equals("card_no") && !entry.getKey().equals("test_mode")) { sb.append(entry.getKey()); sb.append(PARAM_EQUAL); sb.append(entry.getValue()); sb.append(PARAM_AND); } } String params = sb.toString(); if (sb.toString().endsWith(PARAM_AND)) { params = sb.substring(0, sb.length() - 1); } log.info("待签名串:" + params); return params; } return null; } }