java微信公众号支付示例

开始之前，先准备好：appid、商家号、商户密匙。

工具类：

MD5Util.java

 package com.yiexpress.core.utils.wechat;

 import java.security.MessageDigest;

 /**
  * MD5工具类
  */
 public class MD5Util {
     public final static String MD5(String s) {
         char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};         

         try {
             byte[] btInput = s.getBytes();  

             MessageDigest mdInst = MessageDigest.getInstance("MD5");  

             mdInst.update(btInput);  

             byte[] md = mdInst.digest();  

             int j = md.length;
             char str[] = new char[j * 2];
             int k = 0;
             for (int i = 0; i < j; i++) {
                 byte byte0 = md[i];
                 str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                 str[k++] = hexDigits[byte0 & 0xf];
             }
             String md5Str = new String(str);
             return md5Str;
         } catch (Exception e) {
             e.printStackTrace();
             return null;
         }
     }
 }  

SapUtils.java

 package com.yiexpress.core.utils;
 import java.lang.reflect.*;
 import java.util.List;
 import java.io.IOException;
 import java.io.StringWriter;

 import org.dom4j.Document;
 import org.dom4j.DocumentHelper;
 import org.dom4j.Element;
 import org.dom4j.io.OutputFormat;
 import org.dom4j.io.XMLWriter;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.util.StringUtils;

 public class SapUtils {
     private static final Logger logger = LoggerFactory.getLogger(SapUtils.class);
     /** 根据反射对javabean转成xml文件的格式
      * 以类名为第一标签，所有属性作为第二节点，并放入对应的值，如果属性为空 就不放入该熟悉
      * @param dto 传入的对象
      * @param operationName 操作名称
      * @return
      */
     public static String formatToXml(Object dto,String operationName){
         logger.info("解析当前类{}为指定的xml文档格式的数据",dto.getClass().getName());
         logger.info("当前的同步方法是,{}",operationName);
         String result = null;
         Field fields[]=dto.getClass().getDeclaredFields();//dto 是实体类名称
         //DocumentHelper提供了创建Document对象的方法
         Document document = DocumentHelper.createDocument();

         //添加节点信息
          String className=dto.getClass().getName();
          // 操作的名称
         Element rootElement = document.addElement(operationName);
         try {
             Field.setAccessible(fields, true);
             for (int i = 0; i < fields.length; i++) {
                 //添加节点信息
                 if(!StringUtils.isEmpty(fields[i].get(dto))){
                     Class<?> type = fields[i].getType();
                     // 如果是list
                     if(type == List.class){
                         String listName = fields[i].getName();
                        createElement(rootElement, fields[i].get(dto),listName);
                     }
                     else{
                         Element element = rootElement.addElement(fields[i].getName());
                         element.setText((String) fields[i].get(dto));
                     }
                 }
             }
             // 设置XML文档格式
             OutputFormat outputFormat = OutputFormat.createPrettyPrint();
             // 设置XML编码方式,即是用指定的编码方式保存XML文档到字符串(String),这里也可以指定为GBK或是ISO8859-1
             outputFormat.setEncoding("UTF-8");
             // outputFormat.setSuppressDeclaration(true); //是否生产xml头
             outputFormat.setIndent(true); //设置是否缩进
             outputFormat.setIndent("    "); //以四个空格方式实现缩进
             outputFormat.setNewlines(true); //设置是否换行
             StringWriter stringWriter =null;
             // Writer fileWriter =null;
             // xmlWriter是用来把XML文档写入字符串的(工具)
             XMLWriter xmlWriter = null;
            try {
                    // stringWriter字符串是用来保存XML文档的
                 stringWriter = new StringWriter();
                 // fileWriter = new FileWriter("D:\\modu11le.xml");
                 // xmlWriter是用来把XML文档写入字符串的(工具)
                 xmlWriter = new XMLWriter(stringWriter, outputFormat);
                 // 把创建好的XML文档写入字符串
                 xmlWriter.write(document);
                 //fileWriter.write(stringWriter.toString());
                 result=stringWriter.toString();
             } catch (IOException e) {
                 logger.error("写入数据失败");
                 throw new RuntimeException("写入数据失败"+e);
             }finally{
                  try {
                      if(xmlWriter!=null){
                          xmlWriter.flush();
                          xmlWriter.close();
                      }
 /*                     if(fileWriter!=null){
                          fileWriter.flush();
                          fileWriter.close();
                      }*/

                 } catch (IOException e) {
                     logger.error("关闭输出流出错");
                     throw new RuntimeException("关闭输出流出错"+e);
                 }
             }
         } catch (Exception e) {
             logger.error("添加xml的节点失败"+e);
         }
         logger.error("转换xml结束");
         return result;
     } 

     /**
      * 添加类中的list
      * @param element
      * @param object
      * @param name
      * @return
      * @throws IllegalArgumentException
      * @throws IllegalAccessException
      */
     public static Element createElement(Element element ,Object object,String name ) throws IllegalArgumentException, IllegalAccessException{
         Element nameElement = element.addElement(name);
         List info = (List)object;
         for(int j= 0;j<info.size();j++){
             // 添加row的标签
             Element rowElement = nameElement.addElement("row");
             // 添加 对象的熟悉
             Field fields[]=info.get(j).getClass().getDeclaredFields();//dto 是实体类名称
             Field.setAccessible(fields, true);
             for (int i = 0; i < fields.length; i++) {
                 //添加节点信息
                 if(!StringUtils.isEmpty(fields[i].get(info.get(j)))){
                         Element childElement = rowElement.addElement(fields[i].getName());
                         childElement.setText((String) fields[i].get(info.get(j)));
                 }
             }
         }
         return element;
     }
 }

UnifiedOrderRequest.java

package com.yiexpress.core.utils.wechat;

public class UnifiedOrderRequest {
    private String appid;// 公众账号ID
    private String mch_id;//商户号
    private String device_info; //设备号   否
    private String nonce_str;//随机字符串
    private String sign;//签名
    private String sign_type;//签名类型
    private String body;//商品描述
    private String detail;//商品详情
    private String attach;//附加数据
    private String out_trade_no;//商户订单号
    private String fee_type;//标价币种
    private String total_fee;//标价金额
    private String spbill_create_ip;//终端IP
    private String time_start;//交易起始时间
    private String time_expire;//交易结束时间
    private String goods_tag;//订单优惠标记
    private String notify_url;//通知地址
    private String trade_type;//交易类型
    private String product_id;//商品ID
    private String limit_pay;//指定支付方式
    private String openid;//用户标识
    public String getAppid() {
        return appid;
    }
    public void setAppid(String appid) {
        this.appid = appid;
    }
    public String getMch_id() {
        return mch_id;
    }
    public void setMch_id(String mch_id) {
        this.mch_id = mch_id;
    }
    public String getDevice_info() {
        return device_info;
    }
    public void setDevice_info(String device_info) {
        this.device_info = device_info;
    }
    public String getNonce_str() {
        return nonce_str;
    }
    public void setNonce_str(String nonce_str) {
        this.nonce_str = nonce_str;
    }
    public String getSign() {
        return sign;
    }
    public void setSign(String sign) {
        this.sign = sign;
    }
    public String getSign_type() {
        return sign_type;
    }
    public void setSign_type(String sign_type) {
        this.sign_type = sign_type;
    }
    public String getBody() {
        return body;
    }
    public void setBody(String body) {
        this.body = body;
    }
    public String getDetail() {
        return detail;
    }
    public void setDetail(String detail) {
        this.detail = detail;
    }
    public String getAttach() {
        return attach;
    }
    public void setAttach(String attach) {
        this.attach = attach;
    }
    public String getOut_trade_no() {
        return out_trade_no;
    }
    public void setOut_trade_no(String out_trade_no) {
        this.out_trade_no = out_trade_no;
    }
    public String getFee_type() {
        return fee_type;
    }
    public void setFee_type(String fee_type) {
        this.fee_type = fee_type;
    }
    public String getTotal_fee() {
        return total_fee;
    }
    public void setTotal_fee(String total_fee) {
        this.total_fee = total_fee;
    }
    public String getSpbill_create_ip() {
        return spbill_create_ip;
    }
    public void setSpbill_create_ip(String spbill_create_ip) {
        this.spbill_create_ip = spbill_create_ip;
    }
    public String getTime_start() {
        return time_start;
    }
    public void setTime_start(String time_start) {
        this.time_start = time_start;
    }
    public String getTime_expire() {
        return time_expire;
    }
    public void setTime_expire(String time_expire) {
        this.time_expire = time_expire;
    }
    public String getGoods_tag() {
        return goods_tag;
    }
    public void setGoods_tag(String goods_tag) {
        this.goods_tag = goods_tag;
    }
    public String getNotify_url() {
        return notify_url;
    }
    public void setNotify_url(String notify_url) {
        this.notify_url = notify_url;
    }
    public String getTrade_type() {
        return trade_type;
    }
    public void setTrade_type(String trade_type) {
        this.trade_type = trade_type;
    }
    public String getProduct_id() {
        return product_id;
    }
    public void setProduct_id(String product_id) {
        this.product_id = product_id;
    }
    public String getLimit_pay() {
        return limit_pay;
    }
    public void setLimit_pay(String limit_pay) {
        this.limit_pay = limit_pay;
    }
    public String getOpenid() {
        return openid;
    }
    public void setOpenid(String openid) {
        this.openid = openid;
    }

}

UnifiedOrderRespose.java

package com.yiexpress.core.utils.wechat;

public class UnifiedOrderRespose {
    private String return_code;             //返回状态码
    private String return_msg;              //返回信息
    private String appid;                   //公众账号ID
    private String mch_id;                  //商户号
    private String device_info;             //设备号
    private String nonce_str;               //随机字符串
    private String sign;                    //签名
    private String result_code;             //业务结果
    private String err_code;                //错误代码
    private String err_code_des;            //错误代码描述
    private String trade_type;              //交易类型
    private String prepay_id;               //预支付交易会话标识
    private String code_url;                //二维码链接
    public String getReturn_code() {
        return return_code;
    }
    public void setReturn_code(String return_code) {
        this.return_code = return_code;
    }
    public String getReturn_msg() {
        return return_msg;
    }
    public void setReturn_msg(String return_msg) {
        this.return_msg = return_msg;
    }
    public String getAppid() {
        return appid;
    }
    public void setAppid(String appid) {
        this.appid = appid;
    }
    public String getMch_id() {
        return mch_id;
    }
    public void setMch_id(String mch_id) {
        this.mch_id = mch_id;
    }
    public String getDevice_info() {
        return device_info;
    }
    public void setDevice_info(String device_info) {
        this.device_info = device_info;
    }
    public String getNonce_str() {
        return nonce_str;
    }
    public void setNonce_str(String nonce_str) {
        this.nonce_str = nonce_str;
    }
    public String getSign() {
        return sign;
    }
    public void setSign(String sign) {
        this.sign = sign;
    }
    public String getResult_code() {
        return result_code;
    }
    public void setResult_code(String result_code) {
        this.result_code = result_code;
    }
    public String getErr_code() {
        return err_code;
    }
    public void setErr_code(String err_code) {
        this.err_code = err_code;
    }
    public String getErr_code_des() {
        return err_code_des;
    }
    public void setErr_code_des(String err_code_des) {
        this.err_code_des = err_code_des;
    }
    public String getTrade_type() {
        return trade_type;
    }
    public void setTrade_type(String trade_type) {
        this.trade_type = trade_type;
    }
    public String getPrepay_id() {
        return prepay_id;
    }
    public void setPrepay_id(String prepay_id) {
        this.prepay_id = prepay_id;
    }
    public String getCode_url() {
        return code_url;
    }
    public void setCode_url(String code_url) {
        this.code_url = code_url;
    }
}

WXPayConstants.java

package com.yiexpress.core.utils.wechat;

public class WXPayConstants {
     public enum SignType {
        MD5, HMACSHA256
    }
    public static final String FAIL     = "FAIL";
    public static final String SUCCESS  = "SUCCESS";
    public static final String HMACSHA256 = "HMAC-SHA256";
    public static final String MD5 = "MD5";
    public static final String FIELD_SIGN = "sign";
    public static final String FIELD_SIGN_TYPE = "sign_type";
}

WXPayUtil.java

package com.yiexpress.core.utils.wechat;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.*;
import java.security.MessageDigest;  

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

import com.yiexpress.core.utils.SapUtils;
import com.yiexpress.core.utils.XmlUtil;

import com.yiexpress.core.utils.wechat.WXPayConstants.SignType;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
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 org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.input.SAXBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;  

/**
 * 支付工具类
 */
public class WXPayUtil {
    private static Logger log = LoggerFactory.getLogger(WXPayUtil.class);  

    /**
     * 生成订单对象信息
     * @param orderId 订单号
     * @param appId 微信appId
     * @param mch_id 微信分配的商户ID
     * @param body  支付介绍主体
     * @param price 支付价格（放大100倍）
     * @param spbill_create_ip 终端IP
     * @param notify_url  异步直接结果通知接口地址
     * @param noncestr
     * @return
     */
    public static Map<String,Object> createOrderInfo(Map<String, String> requestMap,String shopKey) {
        //生成订单对象
        UnifiedOrderRequest unifiedOrderRequest = new UnifiedOrderRequest();
        unifiedOrderRequest.setAppid(requestMap.get("appId"));//公众账号ID
        unifiedOrderRequest.setBody(requestMap.get("body"));//商品描述
        unifiedOrderRequest.setMch_id(requestMap.get("mch_id"));//商户号
        unifiedOrderRequest.setNonce_str(requestMap.get("noncestr"));//随机字符串
        unifiedOrderRequest.setNotify_url(requestMap.get("notify_url"));//通知地址
        unifiedOrderRequest.setOpenid(requestMap.get("userWeixinOpenId"));
        unifiedOrderRequest.setDetail(requestMap.get("detail"));//详情
        unifiedOrderRequest.setOut_trade_no(requestMap.get("out_trade_no"));//商户订单号
        unifiedOrderRequest.setSpbill_create_ip(requestMap.get("spbill_create_ip"));//终端IP
        unifiedOrderRequest.setTotal_fee(requestMap.get("payMoney"));  //金额需要扩大100倍:1代表支付时是0.01
        unifiedOrderRequest.setTrade_type("JSAPI");//JSAPI--公众号支付、NATIVE--原生扫码支付、APP--app支付
        SortedMap<String, String> packageParams = new TreeMap<String, String>();
        packageParams.put("appid", unifiedOrderRequest.getAppid());
        packageParams.put("body", unifiedOrderRequest.getBody());
        packageParams.put("mch_id", unifiedOrderRequest.getMch_id());
        packageParams.put("nonce_str", unifiedOrderRequest.getNonce_str());
        packageParams.put("notify_url", unifiedOrderRequest.getNotify_url());
        packageParams.put("openid", unifiedOrderRequest.getOpenid());
        packageParams.put("detail", unifiedOrderRequest.getDetail());
        packageParams.put("out_trade_no", unifiedOrderRequest.getOut_trade_no());
        packageParams.put("spbill_create_ip", unifiedOrderRequest.getSpbill_create_ip());
        packageParams.put("total_fee", unifiedOrderRequest.getTotal_fee());
        packageParams.put("trade_type", unifiedOrderRequest.getTrade_type());

        try {
            unifiedOrderRequest.setSign(generateSignature(packageParams,shopKey));//签名
        } catch (Exception e) {
            e.printStackTrace();
        }
        //将订单对象转为xml格式
        String orderstr=SapUtils.formatToXml(unifiedOrderRequest,"xml").replace("<?xml version=\"1.0\" encoding=\"UTF-8\"?>","");
        log.debug("封装好的统一下单请求数据："+orderstr.replace("__", "_"));
        Map<String,Object> responseMap = new HashMap<String,Object>();
        responseMap.put("orderInfo_toString", orderstr.replace("__", "_"));
        responseMap.put("unifiedOrderRequest",unifiedOrderRequest);
        return responseMap;
    }   

    public static void main(String[] args) {
//         UnifiedOrderRequest ut=new UnifiedOrderRequest();
//         ut.setAppid("wx1234156789");
//         ut.setBody("内容body");
//         ut.setMch_id("商户号");
//         ut.setNonce_str("随机字符串");
//         ut.setNotify_url("回调地址");
//         ut.setOpenid("openid");
//         ut.setDetail("详情");
//         ut.setOut_trade_no("订单号");
//         ut.setSpbill_create_ip("终端IP");
//         ut.setTotal_fee("金额");
//         ut.setTrade_type("调用类型JSAPI");
//         System.out.println("---"+SapUtils.formatToXml(ut,"xml")+"---");
//         UnifiedOrderRequest unifiedOrderRequest = new UnifiedOrderRequest();
//         unifiedOrderRequest.setAppid("dsfsdf");//公众账号ID
//         unifiedOrderRequest.setBody("sdfsdf");//商品描述
//         unifiedOrderRequest.setMch_id("sdfsd");//商户号
//         unifiedOrderRequest.setNonce_str("dfsd");//随机字符串
//         unifiedOrderRequest.setNotify_url("sdfdsf");//通知地址
//         unifiedOrderRequest.setOpenid("sdfsdf");
//
//         unifiedOrderRequest.setTrade_type("JSAPI");//JSAPI--公众号支付、NATIVE--原生扫码支付、APP--app支付
//
//         System.out.println("---"+SapUtils.formatToXml(unifiedOrderRequest,"xml").replace("<?xml version=\"1.0\" encoding=\"UTF-8\"?>","")+"---");
//         String str="<xml><appid>dsfsdf</appid><mch_id>sdfsd</mch_id><nonce_str>dfsd</nonce_str><body>sdfsdf</body><notify_url>sdfdsf</notify_url><trade_type>JSAPI</trade_type><openid>sdfsdf</openid></xml>";
//         UnifiedOrderRequest s=SapUtils.getBeanByxml(str,UnifiedOrderRequest.class);
//         System.out.println(s.getAppid()+"---"+s.getMch_id()+"--"+s.getFee_type());

    }

    /**
     * 生成签名
     * @param appid_value
     * @param mch_id_value
     * @param productId
     * @param nonce_str_value
     * @param trade_type
     * @param notify_url
     * @param spbill_create_ip
     * @param total_fee
     * @param out_trade_no
     * @return
     */
    private static String createSign(UnifiedOrderRequest unifiedOrderRequest,String shopKey) {
        //根据规则创建可排序的map集合
        SortedMap<String, String> packageParams = new TreeMap<String, String>();
        packageParams.put("appid", unifiedOrderRequest.getAppid());
        packageParams.put("body", unifiedOrderRequest.getBody());
        packageParams.put("mch_id", unifiedOrderRequest.getMch_id());
        packageParams.put("nonce_str", unifiedOrderRequest.getNonce_str());
        packageParams.put("notify_url", unifiedOrderRequest.getNotify_url());
        packageParams.put("out_trade_no", unifiedOrderRequest.getOut_trade_no());
        packageParams.put("spbill_create_ip", unifiedOrderRequest.getSpbill_create_ip());
        packageParams.put("trade_type", unifiedOrderRequest.getTrade_type());
        packageParams.put("total_fee", unifiedOrderRequest.getTotal_fee());
        StringBuffer sb = new StringBuffer();
        Set es = packageParams.entrySet();//字典序
        Iterator it = es.iterator();
        while (it.hasNext()) {
            Map.Entry entry = (Map.Entry) it.next();
            String k = (String) entry.getKey();
            String v = (String) entry.getValue();
            //为空不参与签名、参数名区分大小写
            if (null != v && !"".equals(v) && !"sign".equals(k)  && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        //第二步拼接key，key设置路径：微信商户平台(pay.weixin.qq.com)-->账户设置-->API安全-->密钥设置
        sb.append("key="+shopKey);
        String sign = MD5Util.MD5(sb.toString()).toUpperCase();//MD5加密
        log.error("方式一生成的签名="+sign);
        return sign;
    }    

    //xml解析
    public static SortedMap<String, String> doXMLParseWithSorted(String strxml) throws Exception {
          strxml = strxml.replaceFirst("encoding=\".*\"", "encoding=\"UTF-8\"");
          if(null == strxml || "".equals(strxml)) {
              return null;
          }
          SortedMap<String,String> m = new TreeMap<String,String>();
          InputStream in = new ByteArrayInputStream(strxml.getBytes("UTF-8"));
          SAXBuilder builder = new SAXBuilder();
          Document doc = builder.build(in);
          Element root = doc.getRootElement();
          List list = root.getChildren();
          Iterator it = list.iterator();
          while(it.hasNext()) {
              Element e = (Element) it.next();
              String k = e.getName();
              String v = "";
              List children = e.getChildren();
              if(children.isEmpty()) {
                  v = e.getTextNormalize();
              } else {
                  v = getChildrenText(children);
              }
              m.put(k, v);
          }
          //关闭流
          in.close();
          return m;
    }     

    public static String getChildrenText(List children) {
        StringBuffer sb = new StringBuffer();
        if(!children.isEmpty()) {
            Iterator it = children.iterator();
            while(it.hasNext()) {
                Element e = (Element) it.next();
                String name = e.getName();
                String value = e.getTextNormalize();
                List list = e.getChildren();
                sb.append("<" + name + ">");
                if(!list.isEmpty()) {
                    sb.append(getChildrenText(list));
                }
                sb.append(value);
                sb.append("</" + name + ">");
            }
        }
        return sb.toString();
    }
    /**
     * 调统一下单API
     * @param orderInfo
     * @return
     */
    public static UnifiedOrderRespose httpOrder(String orderInfo,int index) {
        //统一下单接口地址 自动适应  1中国境内  2东南亚   3其他
        String[] urlList={"https://api.mch.weixin.qq.com/pay/unifiedorder","https://apihk.mch.weixin.qq.com/pay/unifiedorder"
                ,"https://apius.mch.weixin.qq.com/pay/unifiedorder "};
        //String url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
        try {
            HttpURLConnection conn = (HttpURLConnection) new URL(urlList[index]).openConnection();
            //加入数据
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            BufferedOutputStream buffOutStr = new BufferedOutputStream(conn.getOutputStream());
            buffOutStr.write(orderInfo.getBytes("UTF-8"));
            buffOutStr.flush();
            buffOutStr.close();
            //获取输入流
            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
            String line = null;
            StringBuffer sb = new StringBuffer();
            while((line = reader.readLine())!= null){
                sb.append(line);
            }
            //xml转对象
            UnifiedOrderRespose unifiedOrderRespose =XmlUtil.getBeanByxml(sb.toString(),UnifiedOrderRespose.class);
            return unifiedOrderRespose;
        } catch (Exception 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>();
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder = documentBuilderFactory.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 {
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder= documentBuilderFactory.newDocumentBuilder();
        org.w3c.dom.Document document = documentBuilder.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;
    }  

    /**
     * 生成带有 sign 的 XML 格式字符串
     *
     * @param data Map类型数据
     * @param key API密钥
     * @return 含有sign字段的XML
     */
    public static String generateSignedXml(final Map<String, String> data, String key) throws Exception {
        return generateSignedXml(data, key, SignType.MD5);
    }  

    /**
     * 生成带有 sign 的 XML 格式字符串
     *
     * @param data Map类型数据
     * @param key API密钥
     * @param signType 签名类型
     * @return 含有sign字段的XML
     */
    public static String generateSignedXml(final Map<String, String> data, String key, SignType signType) throws Exception {
        String sign = generateSignature(data, key, signType);
        data.put(WXPayConstants.FIELD_SIGN, sign);
        return mapToXml(data);
    }  

    /**
     * 判断签名是否正确
     *
     * @param xmlStr XML格式数据
     * @param key API密钥
     * @return 签名是否正确
     * @throws Exception
     */
    public static boolean isSignatureValid(String xmlStr, String key) throws Exception {
        Map<String, String> data = xmlToMap(xmlStr);
        if (!data.containsKey(WXPayConstants.FIELD_SIGN) ) {
            return false;
        }
        String sign = data.get(WXPayConstants.FIELD_SIGN);
        return generateSignature(data, key).equals(sign);
    }  

    /**
     * 判断签名是否正确，必须包含sign字段，否则返回false。使用MD5签名。
     *
     * @param data Map类型数据
     * @param key API密钥
     * @return 签名是否正确
     * @throws Exception
     */
    public static boolean isSignatureValid(Map<String, String> data, String key) throws Exception {
        return isSignatureValid(data, key, SignType.MD5);
    }  

    /**
     * 判断签名是否正确，必须包含sign字段，否则返回false。
     *
     * @param data Map类型数据
     * @param key API密钥
     * @param signType 签名方式
     * @return 签名是否正确
     * @throws Exception
     */
    public static boolean isSignatureValid(Map<String, String> data, String key, SignType signType) throws Exception {
        if (!data.containsKey(WXPayConstants.FIELD_SIGN) ) {
            return false;
        }
        String sign = data.get(WXPayConstants.FIELD_SIGN);
        return generateSignature(data, key, signType).equals(sign);
    }  

    /**
     * 生成签名
     *
     * @param data 待签名数据
     * @param key API密钥
     * @return 签名
     */
    public static String generateSignature(final Map<String, String> data, String key) throws Exception {
        return generateSignature(data, key, SignType.MD5);
    }  

    /**
     * 生成签名. 注意，若含有sign_type字段，必须和signType参数保持一致。
     *
     * @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, SignType 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(WXPayConstants.FIELD_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 (SignType.MD5.equals(signType)) {
            return MD5(sb.toString()).toUpperCase();
        }
        else if (SignType.HMACSHA256.equals(signType)) {
            return HMACSHA256(sb.toString(), key);
        }
        else {
            log.error("获取签名失败，失败原因："+String.format("Invalid sign_type: %s", signType));
            throw new Exception(String.format("Invalid sign_type: %s", signType));
        }
    }  

    /**
     * 获取随机字符串 Nonce Str
     * @return String 随机字符串
     */
    public static String generateNonceStr() {
        return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 32);
    }
    /**
     * Map转xml数据
     */
    public static String GetMapToXML(Map<String,String> param){
        StringBuffer sb = new StringBuffer();
        sb.append("<xml>");
        for (Map.Entry<String,String> entry : param.entrySet()) {
            sb.append("<"+ entry.getKey() +">");
            sb.append(entry.getValue());
            sb.append("</"+ entry.getKey() +">");
        }
        sb.append("</xml>");
        return sb.toString();
    }    

    /**
     * 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();
    }  

    /**
     * 日志
     * @return
     */
    public static Logger getLogger() {
        Logger logger = LoggerFactory.getLogger("wxpay java sdk");
        return logger;
    }  

    /**
     * 获取当前时间戳，单位秒
     * @return
     */
    public static long getCurrentTimestamp() {
        return System.currentTimeMillis()/1000;
    }  

    /**
     * 获取当前时间戳，单位毫秒
     * @return
     */
    public static long getCurrentTimestampMs() {
        return System.currentTimeMillis();
    }  

    /**
     * 生成 uuid， 即用来标识一笔单，也用做 nonce_str
     * @return
     */
    public static String generateUUID() {
        return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 32);
    }  

    /**
     * 支付签名
     * @param timestamp
     * @param noncestr
     * @param packages
     * @return
     * @throws UnsupportedEncodingException
     */
    public static String paySign(String timestamp, String noncestr,String packages,String appId){
        Map<String, String> paras = new HashMap<String, String>();
        paras.put("appid", appId);
        paras.put("timestamp", timestamp);
        paras.put("noncestr", noncestr);
        paras.put("package", packages);
        paras.put("signType", "MD5");
        StringBuffer sb = new StringBuffer();
        Set es = paras.entrySet();//字典序
        Iterator it = es.iterator();
        while (it.hasNext()) {
            Map.Entry entry = (Map.Entry) it.next();
            String k = (String) entry.getKey();
            String v = (String) entry.getValue();
            //为空不参与签名、参数名区分大小写
            if (null != v && !"".equals(v) && !"sign".equals(k)  && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        String sign = MD5Util.MD5(sb.toString()).toUpperCase();//MD5加密
        return sign;
    }
}  

XmlUtil.java

 package com.yiexpress.core.utils;
 import java.io.StringReader;
 import java.lang.reflect.Field;
 import java.util.Date;  

 import org.dom4j.Document;
 import org.dom4j.Element;
 import org.dom4j.io.SAXReader;
 import org.xml.sax.InputSource;

 public class XmlUtil{
     /**
      * json 数据转换对象
      *
      * @param Element
      *            要转换的Element数据
      * @param pojo
      *            要转换的目标对象类型
      * @return 转换的目标对象
      * @throws Exception
      *             转换失败
      */
     @SuppressWarnings("rawtypes")
     public static Object fromXmlToBean(Element rootElt, Class pojo) throws Exception{
         // 首先得到pojo所定义的字段
         Field[] fields = pojo.getDeclaredFields();
         // 根据传入的Class动态生成pojo对象
         Object obj = pojo.newInstance();
         for (Field field : fields)
         {
             // 设置字段可访问（必须，否则报错）
             field.setAccessible(true);
             // 得到字段的属性名
             String name = field.getName();
             // 这一段的作用是如果字段在Element中不存在会抛出异常，如果出异常，则跳过。
             try
             {
                 rootElt.elementTextTrim(name);
             }
             catch (Exception ex)
             {
                 continue;
             }
             if (rootElt.elementTextTrim(name) != null && !"".equals(rootElt.elementTextTrim(name)))
             {
                 // 根据字段的类型将值转化为相应的类型，并设置到生成的对象中。
                 if (field.getType().equals(Long.class) || field.getType().equals(long.class))
                 {
                     field.set(obj, Long.parseLong(rootElt.elementTextTrim(name)));
                 }
                 else if (field.getType().equals(String.class))
                 {
                     field.set(obj, rootElt.elementTextTrim(name));
                 }
                 else if (field.getType().equals(Double.class) || field.getType().equals(double.class))
                 {
                     field.set(obj, Double.parseDouble(rootElt.elementTextTrim(name)));
                 }
                 else if (field.getType().equals(Integer.class) || field.getType().equals(int.class))
                 {
                     field.set(obj, Integer.parseInt(rootElt.elementTextTrim(name)));
                 }
                 else if (field.getType().equals(java.util.Date.class))
                 {
                     field.set(obj, Date.parse(rootElt.elementTextTrim(name)));
                 }
                 else
                 {
                     continue;
                 }
             }
         }
         return obj;
     }  

     /**
      * 把xml格式转化为指定对象
      *
      * @param xml
      * @return
      */
     @SuppressWarnings("unchecked")
     public static <T> T getBeanByxml(String xml, Class<T> valueType) {
         T person = null;
         InputSource in = new InputSource(new StringReader(xml));
         in.setEncoding("UTF-8");
         SAXReader reader = new SAXReader();
         Document document;
         try {
             document = reader.read(in);
             Element root = document.getRootElement();
             person = (T) XmlUtil.fromXmlToBean(root, valueType);  

         } catch (Exception e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
             System.out.println("数据解析错误");  

         }
         return person;
     }
 }  

获取预支付ID和签名的controller

package com.yiexpress.jerry.controller.ewe.wechat;

import java.util.HashMap;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;

import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

import com.yiexpress.core.utils.wechat.UnifiedOrderRequest;
import com.yiexpress.core.utils.wechat.UnifiedOrderRespose;
import com.yiexpress.core.utils.wechat.WXPayUtil;

/**
 * 微信支付controller
 */
@Controller
@RequestMapping(value = "/wxpay")
public class WXPayController{
    private static final Logger LOGGER = LoggerFactory.getLogger(WXPayController.class);

    private String appId="公总号 appid";//公总号 appid
    private String mchId="商家号";//商家号
    private String apiKey="商户密匙";//商户密匙

    /**
     * 获取终端IP
     * @param request
     * @return
     */
    public static String getIpAddr(HttpServletRequest request)  {
        String ip  =  request.getHeader( " x-forwarded-for " );
        if (ip == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip))  {
            ip = request.getHeader( " Proxy-Client-IP " );
        }
        if (ip  == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip))  {
            ip  =  request.getHeader( " WL-Proxy-Client-IP " );
        }
        if (ip  == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip))  {
            ip  =  request.getRemoteAddr();
        }
        return  ip;
     }   

    /**
     * 支付初始化   返回预支付ID、签名等信息
     * @param payMoney
     * @return  map
     * result  -1
     */
    @RequestMapping("/toPayInit")
    @ResponseBody
    public Map<String,Object> toPay(HttpServletRequest request,@RequestParam(value="payMoney",required=true)float payMoney,@RequestParam(value="openId",required=true) String openId,@RequestParam(value="orderId",required=true)String orderId){
        Map<String,Object> map = new HashMap<>();
        //订单号 目前生产的随机数  后面放入指定系统唯一的单号
        //判断单号是否存在
        String noncestr = WXPayUtil.generateNonceStr();
        Map<String,String> requestMap = new HashMap<String, String>();
        requestMap.put("appId",appId);
        requestMap.put("userWeixinOpenId",openId);
        //之前使用ETCA单号作为商户订单号，现在改为自动生成的账单号    2018-10-25 Peter
        //requestMap.put("out_trade_no",auShipmentBrief.getShipmentReference());
        requestMap.put("out_trade_no","订单号");
        requestMap.put("mch_id",mchId);
        //计算金额   微信支付的金额的单位是分，例如：实际支付1.23元，传入参数就是123
        int money=0;
        try {
            money=(int)(payMoney*100);
        } catch (Exception e) {
            map.put("result",-1);
            map.put("msg","金额格式不正确");
            return map;
        }

        requestMap.put("payMoney",money+"");
        requestMap.put("spbill_create_ip", getIpAddr(request));
        requestMap.put("notify_url","回调地址");
        requestMap.put("noncestr", noncestr);
        requestMap.put("body","微信下单账单支付");
        requestMap.put("detail","散客下单账单支付");
        Map<String,Object> requestInfo = WXPayUtil.createOrderInfo(requestMap,apiKey);
        String orderInfo_toString = (String) requestInfo.get("orderInfo_toString");
        LOGGER.debug("request 请求字符串:"+orderInfo_toString);
         //判断返回码
        UnifiedOrderRespose orderResponse = WXPayUtil.httpOrder(orderInfo_toString,0);// 调用统一下单接口
        //判断超时的情况
        if(orderResponse==null || orderResponse.getReturn_code()==null || ("SUCCESS".equals(orderResponse.getReturn_code()) && (orderResponse.getErr_code()==null || "SYSTEMERROR".equals(orderResponse.getErr_code())))){
            orderResponse = WXPayUtil.httpOrder(orderInfo_toString,1);
            if(orderResponse==null || orderResponse.getReturn_code()==null || ("SUCCESS".equals(orderResponse.getReturn_code()) && (orderResponse.getErr_code()==null || "SYSTEMERROR".equals(orderResponse.getErr_code())))){
                orderResponse = WXPayUtil.httpOrder(orderInfo_toString,2);
            }
        }

        LOGGER.debug("response 返回字段:==》{}",orderResponse);
        //根据微信文档return_code 和result_code都为SUCCESS的时候才会返回code_url
        if(null!=orderResponse  && "SUCCESS".equals(orderResponse.getReturn_code()) && "SUCCESS".equals(orderResponse.getResult_code())){
            String timestamp = String.valueOf(WXPayUtil.getCurrentTimestamp());
            map.put("timestamp",timestamp);
            map.put("noncestr",noncestr);
            UnifiedOrderRequest unifiedOrderRequest = (UnifiedOrderRequest) requestInfo.get("unifiedOrderRequest");
            map.put("unifiedOrderRequest",unifiedOrderRequest);
            SortedMap<String, String> packageParams = new TreeMap<String, String>();
            packageParams.put("appId",appId);
            packageParams.put("signType","MD5");
            packageParams.put("nonceStr", noncestr);
            packageParams.put("timeStamp", timestamp);
            String packages = "prepay_id="+orderResponse.getPrepay_id();
            packageParams.put("package",packages); 

            String sign = null;
            try {
                //生成签名
                sign = WXPayUtil.generateSignature(packageParams,apiKey);
            } catch (Exception e) {
                map.put("result",-1);
                map.put("msg","支付签名信息异常");
                e.printStackTrace();
            }
            if(sign!=null && !"".equals(sign)){ 

                LOGGER.debug("------------支付签名："+sign+"-------------------");
                map.put("paySign",sign);
                map.put("result",1);
                map.put("appId",appId);
            }else{
                map.put("result",-1);
                map.put("msg","支付签名信息异常");
            } 

            map.put("prepay_id",orderResponse.getPrepay_id());
            return map;
        }else{ //不成功
            if(orderResponse!=null){
                String text = "调用微信支付出错，返回状态码："+orderResponse.getReturn_code()+"，返回信息："+orderResponse.getReturn_msg();
                if(orderResponse.getErr_code()!=null && !"".equals(orderResponse.getErr_code())){
                    text = text +"，错误码："+orderResponse.getErr_code()+"，错误描述："+orderResponse.getErr_code_des();
                }
                LOGGER.error(text);
            }else{
                LOGGER.error("返回值   orderResponse对象为空");
            }
            map.put("result",-1);
            map.put("msg","支付环境异常,请稍后再试");
            return map;
        }
    }  

}  

jsp代码

 <script type="text/javascript">

 //点击支付按钮 开始支付
 function toPay(){  

     //初步判断数据
     var openId=$("#openId").val();
     var payMoney=$("#payMoney").val();
     $.ajax({
         url : "${pageContext.request.contextPath}/toPayInit",
         type:"POST",
         dataType : 'json',
         data:{
             payMoney:payMoney,
             openId:openId,
             orderId:"订单号"
         },
         success : function(result) {
             if(result.result==1){
                 var paySign = result.paySign;
                 var prepay_id = result.prepay_id;
                 var nonceStr = result.noncestr;
                 var timestamp = result.timestamp;
                 var unifiedOrderRequest = result.unifiedOrderRequest;
                 var spbill_create_ip = unifiedOrderRequest.spbill_create_ip;
                 var detail = unifiedOrderRequest.detail;
                 var out_trade_no = unifiedOrderRequest.out_trade_no;
                 var appId=result.appId;
                 onBridgeReady(paySign,prepay_id,nonceStr,timestamp,appId);
             }else{
                 alert("失败");
             }
         },
         error : function(data, status, e) { // 服务器响应失败时的处理函数
             alert("数据异常,支付失败", 'error');
         }
     });
 }

 //调起公众号支付
 function onBridgeReady(paySign,prepay_id,nonceStr,timestamp,appId){
    WeixinJSBridge.invoke(
        'getBrandWCPayRequest', {
            "appId":appId,     //appid
            "timeStamp":timestamp,
            "nonceStr":nonceStr, //随机串
            "package":"prepay_id="+prepay_id,
            "signType":"MD5",
            "paySign":paySign //微信签名
        },
        function(res){
             // 使用以上方式判断前端返回,微信团队郑重提示：res.err_msg将在用户支付成功后返回    ok，但并不保证它绝对可靠。
            if(res.err_msg == "get_brand_wcpay_request:ok" ) {
                alert("支付完成", 'success');
            }else if(res.err_msg == "get_brand_wcpay_request:cancel" ) {
                alert("取消支付", 'success');  

            }else if(res.err_msg == "get_brand_wcpay_request:fail"){
                alert("支付失败", 'success');

            }
        }
    );
 }
 </script>

定义微信支付成功回调接口APIAupostController.java

 package com.yiexpress.api.controller.ewe.aupost;

 import java.util.HashMap;
 import java.util.Map;

 import javax.annotation.Resource;
 import javax.servlet.ServletInputStream;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.collections.MapUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;

 import com.yiexpress.core.utils.wechat.WXPayUtil;
 @Controller
 @RequestMapping("/api")
 public class APIAupostController {

     private static final Logger LOGGER=LoggerFactory.getLogger(APIAupostController.class);

     @Resource(name = "jacksonBean")
     private MappingJackson2HttpMessageConverter jackson;
     private String apiKey="商户密匙";//商户密匙

      /**
          * 异步回调接口
          * @param request
          * @param response
          * @throws Exception
          */
         @RequestMapping(value="/paymentNotice",produces="text/html;charset=utf-8")
         @ResponseBody
         public String WeixinParentNotifyPage(HttpServletRequest request,HttpServletResponse response) throws Exception{
             ServletInputStream instream = request.getInputStream();
             StringBuffer sb = new StringBuffer();
             int len = -1;
             byte[] buffer = new byte[1024];
             while((len = instream.read(buffer)) != -1){
                 sb.append(new String(buffer,0,len));
             }
             instream.close();
             Map<String,String> map = WXPayUtil.xmlToMap(sb.toString());//接受微信的回调的通知参数
             Map<String,String> return_data = new HashMap<String,String>();
             //判断签名是否正确
             if(WXPayUtil.isSignatureValid(map,apiKey)){
                 if(map.get("return_code").toString().equals("FAIL")){
                     return_data.put("return_code", "FAIL");
                     return_data.put("return_msg", map.get("return_msg"));
                 }else {
                     String return_code=MapUtils.getString(map,"return_code");
                     String result_code=MapUtils.getString(map,"result_code");
                     if(return_code!=null && "SUCCESS".equals(return_code) && result_code!=null && "SUCCESS".equals(result_code)){
                         String out_trade_no =MapUtils.getString(map,"out_trade_no");//系统订单号
                         //支付成功,可以自定义新逻辑

                     }
                 }
             }else{
                 return_data.put("return_code", "FAIL");
                 return_data.put("return_msg", "签名错误");
             }
             String xml = WXPayUtil.GetMapToXML(return_data);
             LOGGER.error("支付通知回调结果："+xml);
             return xml;
         }

 }

完工！