【java】微信支付工具类封装

package cn.jishupeng.springbootWxpay.utils;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.StringWriter;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;

public class CommonUtil {

    static String[] chars = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};

    public static String generateUUid() {
        String uuid = UUID.randomUUID().toString().replaceAll("-", "");
        return uuid;
    }

    public static String MD5(String data) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("md5");
            byte[] result = md5.digest(data.getBytes());
            StringBuilder sb  = new StringBuilder(32);

            for (int i = 0; i < result.length; i++) {
                // 一个字节对应两个字符
                byte x = result[i];
                // 取得高位
                int h = 0x0f & (x >>> 4);
                // 取得低位
                int l = 0x0f & x;
                sb.append(chars[h]).append(chars[l]);
            }
            return sb.toString();

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * XML格式字符串转换为Map
     *
     * @param strXML XML字符串
     * @return XML数据转换后的Map
     * @throws Exception
     */
    public static Map<String, String> xmlToMap(String strXML) throws Exception {
        try {
            Map<String, String> data = new HashMap<String, String>();
            DocumentBuilder documentBuilder = WXPayXmlUtil.newDocumentBuilder();
            InputStream stream = new ByteArrayInputStream(strXML.getBytes("UTF-8"));
            org.w3c.dom.Document doc = documentBuilder.parse(stream);
            doc.getDocumentElement().normalize();
            NodeList nodeList = doc.getDocumentElement().getChildNodes();
            for (int idx = 0; idx < nodeList.getLength(); ++idx) {
                Node node = nodeList.item(idx);
                if (node.getNodeType() == Node.ELEMENT_NODE) {
                    org.w3c.dom.Element element = (org.w3c.dom.Element) node;
                    data.put(element.getNodeName(), element.getTextContent());
                }
            }
            try {
                stream.close();
            } catch (Exception ex) {
                // do nothing
            }
            return data;
        } catch (Exception ex) {
            WXPayUtil.getLogger().warn("Invalid XML, can not convert to map. Error message: {}. XML content: {}", ex.getMessage(), strXML);
            throw ex;
        }

    }

    /**
     * 将Map转换为XML格式的字符串
     *
     * @param data Map类型数据
     * @return XML格式的字符串
     * @throws Exception
     */
    public static String mapToXml(Map<String, String> data) throws Exception {
        org.w3c.dom.Document document = WXPayXmlUtil.newDocument();
        org.w3c.dom.Element root = document.createElement("xml");
        document.appendChild(root);
        for (String key: data.keySet()) {
            String value = data.get(key);
            if (value == null) {
                value = "";
            }
            value = value.trim();
            org.w3c.dom.Element filed = document.createElement(key);
            filed.appendChild(document.createTextNode(value));
            root.appendChild(filed);
        }
        TransformerFactory tf = TransformerFactory.newInstance();
        Transformer transformer = tf.newTransformer();
        DOMSource source = new DOMSource(document);
        transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
        transformer.setOutputProperty(OutputKeys.INDENT, "yes");
        StringWriter writer = new StringWriter();
        StreamResult result = new StreamResult(writer);
        transformer.transform(source, result);
        String output = writer.getBuffer().toString(); //.replaceAll("\n|\r", "");
        try {
            writer.close();
        }
        catch (Exception ex) {
        }
        return output;
    }


    /*
    * sign签名方法
    * */
    public static String createSign(SortedMap<String, String> params, String key) {
        StringBuilder sb = new StringBuilder();
        Set<Map.Entry<String, String>> entries = params.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            String k = entry.getKey();
            String v = entry.getValue();

            if (!"sign".equals(k) && !"".equals(k) && null != k && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        String sign = sb.append("key=").append(key).toString();

        // 得到sign之后进行md5加密
        String sign_md5 = CommonUtil.MD5(sign).toUpperCase();

        return sign_md5;
    }

    /*
    * 校验sign方法
    * */
    public static boolean isCorrectSign(SortedMap<String, String> params, String key) {
        String sign_md5 = createSign(params, key);

        String sign1 = params.get("sign").toUpperCase();

        return sign1.equals(sign_md5);
    }

    /*
    * 获取一个有序map
    * */
    public static SortedMap<String, String> getSortedMap(Map<String, String> map) {
        SortedMap<String, String> sortedMap = new TreeMap<>();
        Set<Map.Entry<String, String>> entries = map.entrySet();
        for (Map.Entry<String, String> entry : entries) {
            String key = entry.getKey();
            String value = entry.getValue();
            if (null != value) {
                sortedMap.put(key, value.trim());
            }
        }
        return sortedMap;
    }
}