首先是微信支付的配置类：WxPayConfig

public class WxPayConfig {
    //小程序appid
    public static final String appid = "wx9eb0dffa5de476ba";
    //微信支付的商户id
    public static final String mch_id = "xxxxxx";//商户号
    //微信支付的商户密钥
    public static final String key = "xxxxxxxxxxxxxxxxxxxx";//商户的key
    //支付成功后的服务器回调url,回调函数的地址（就是自己写在Controller里的回调函数）但是不许外网能访问（可以进行内网穿透）
    public static final String notify_url = "https://live.tinyshark.com.cn/wxNotify";
    //签名方式
    public static final String SIGNTYPE = "MD5";
    //交易类型
    public static final String TRADETYPE = "jsAPI";
    //微信统一下单接口地址
    public static final String pay_url = "https://api.mch.weixin.qq.com/pay/unifiedorder";

}

然后写我们微信支付的接口和回调函数的接口：PayController

package com.lbm.controller;

import com.lbm.config.WxPayConfig;
import com.lbm.pojo.Invite;
import com.lbm.pojo.Order;
import com.lbm.pojo.YuZhiFu;
import com.lbm.service.Impl.InviteServiceImpl;
import com.lbm.service.Impl.OrderServiceImpl;
import com.lbm.service.Impl.YuZhiFuServiceImpl;
import com.lbm.utils.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


@Controller
public class PayController {
   
    @Autowired
    YuZhiFuServiceImpl yuZhiFuService;

    YuZhiFu yuZhiFu=new YuZhiFu();

    @Autowired
    InviteServiceImpl inviteService;

    Invite invite=new Invite();

    @RequestMapping("wxPay")
    @ResponseBody
    //这里面的参数都是我需要的参数你们可以不要（只要HttpServletRequest request）
    public Map wxPay(String money,String oldtoken,String openid, HttpServletRequest request,String kname,String bname,String times,String bsex,String phone){


        try{
            //微信里面的价格是以分为单位

            //生成的随机字符串
            String nonce_str = StringUtils.getRandomStringByLength(32);
            //商户订单号
            String out_trade_no= new RandomUtil().getRandomCode(10);
            //商品名称
            String body = "寒假钜惠抢先购";
            //获取客户端的ip地址
            String spbill_create_ip = IpUtils.getIpAddr(request);
            //组装参数，用户生成统一下单接口的签名
            Map packageParams = new HashMap();
            packageParams.put("appid", WxPayConfig.appid);
            packageParams.put("mch_id", WxPayConfig.mch_id);
            packageParams.put("nonce_str", nonce_str);
            packageParams.put("body", body);
            packageParams.put("out_trade_no", out_trade_no);//商户订单号
            packageParams.put("total_fee", money);//支付金额，这边需要转成字符串类型，否则后面的签名会失败
            packageParams.put("spbill_create_ip", spbill_create_ip);
            packageParams.put("notify_url", WxPayConfig.notify_url);//支付成功后的回调地址
            packageParams.put("trade_type", WxPayConfig.TRADETYPE);//支付方式
            packageParams.put("openid", openid);

            String prestr = PayUtil.createLinkString(packageParams); // 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串

            //MD5运算生成签名，这里是第一次签名，用于调用统一下单接口
            String mysign = PayUtil.sign(prestr, WxPayConfig.key, "utf-8").toUpperCase();

            //拼接统一下单接口使用的xml数据，要将上一步生成的签名一起拼接进去
            String xml = "" + "" + WxPayConfig.appid + ""
                    + " + body + "]]>"
                    + "" + WxPayConfig.mch_id + ""
                    + "" + nonce_str + ""
                    + "" + WxPayConfig.notify_url + ""
                    + "" + openid + ""
                    + "" + out_trade_no + ""
                    + "" + spbill_create_ip + ""
                    + "" + money + ""
                    + "" + WxPayConfig.TRADETYPE + ""
                    + "" + mysign + ""
                    + "";
            System.out.println("调试模式_统一下单接口 请求XML数据：" + xml);
            //调用统一下单接口，并接受返回的结果
            String result = PayUtil.httpRequest(WxPayConfig.pay_url, "POST", xml);

            //这里是我处理的一些逻辑（你们可以自己写自己的逻辑，这里也可以不写）————将预支付状态存入数据库，等支付成功后改支付状态为已支付。这里面的参数就对应上面那些可以不用的参数
            Date date = new Date();
            String trackTime = DateUtils.formateTrackTime(date);
            yuZhiFu.setBody(body);
            yuZhiFu.setOldtoken(oldtoken);
            yuZhiFu.setKname(kname);
            yuZhiFu.setBname(bname);
            yuZhiFu.setTimes(times);
            yuZhiFu.setBsex(bsex);
            yuZhiFu.setStatus("0");//默认支付状态为0，支付成功后在处理微信回调的逻辑中将它改成已支付
            yuZhiFu.setPhone(phone);
            yuZhiFu.setToken(openid);
            yuZhiFu.setOut_trade_no(out_trade_no);
            yuZhiFu.setBuytime(trackTime);
            yuZhiFu.setTotal_fee(Integer.parseInt(money)/100+"");
            yuZhiFuService.insertYuZhiFu(yuZhiFu);


            System.out.println("调试模式_统一下单接口 返回XML数据：" + result);
            // 将解析结果存储在HashMap中
            Map map = PayUtil.doXMLParse(result);
            System.out.println(map);
            String return_code = (String) map.get("return_code");//返回状态码
            Map response = new HashMap();//返回给小程序端需要的参数
            if(return_code.equals("SUCCESS")){
                String prepay_id = String.valueOf(map.get("prepay_id"));//返回的预付单信息
                response.put("nonceStr", nonce_str);
                response.put("package", "prepay_id=" + prepay_id);
                Long timeStamp = System.currentTimeMillis() / 1000;
                response.put("timeStamp", timeStamp + "");//这边要将返回的时间戳转化成字符串，不然小程序端调用wx.requestPayment方法会报签名错误
                //拼接签名需要的参数
                String stringSignTemp = "appId=" + WxPayConfig.appid + "&nonceStr=" + nonce_str + "&package=prepay_id=" + prepay_id+ "&signType=MD5&timeStamp=" + timeStamp;
                //再次签名，这个签名用于小程序端调用wx.requesetPayment方法
                String paySign = PayUtil.sign(stringSignTemp, WxPayConfig.key, "utf-8").toUpperCase();
                response.put("paySign", paySign);
            }
            response.put("appid", WxPayConfig.appid);
            return response;
        }catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }




    /**
     * @Description:微信支付的回调函数
     * @return
     * @throws "Exception"
     */
    @RequestMapping("wxNotify")
    @ResponseBody
    public String wxNotify(HttpServletRequest request, HttpServletResponse response) throws Exception{


        System.out.println("进入了回调》》》》》》》》》》》》》》》》》》》》》》》》");
        BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine()) != null){
            sb.append(line);
        }
        br.close();
        //sb为微信返回的xml
        String notityXml = sb.toString();
        String resXml = "";
        System.out.println("接收到的报文：" + notityXml);

        Map map = PayUtil.doXMLParse(notityXml);

        String returnCode = (String) map.get("return_code");
        if("SUCCESS".equals(returnCode)){
            //验证签名是否正确
            Map validParams = PayUtil.paraFilter(map);  //回调验签时需要去除sign和空值参数
            String validStr = PayUtil.createLinkString(validParams);//把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
            String sign = PayUtil.sign(validStr, WxPayConfig.key, "utf-8").toUpperCase();//拼装生成服务器端验证的签名

            //根据微信官网的介绍，此处不仅对回调的参数进行验签，还需要对返回的金额与系统订单的金额进行比对等
            if(sign.equals(map.get("sign"))){
                /**此处添加自己的业务逻辑代码start**/
                System.out.println("开始=================");
                String out_trade_no=(String) map.get("out_trade_no");
                String transaction_id=(String) map.get("transaction_id");
                //买的人token
                String token=(String) map.get("openid");
                Date date = new Date();
                String time_end = DateUtils.formateTrackTime(date);

                HashMap stringHashMap = new HashMap<>();
                stringHashMap.put("status","已支付");//这里将微信支付改成已支付
                stringHashMap.put("buytime",time_end);
                stringHashMap.put("transaction_id",transaction_id);
                stringHashMap.put("out_trade_no",out_trade_no);
                yuZhiFuService.updateYuZhiFu(stringHashMap);
                List orders = yuZhiFuService.queryByTokenCourse(stringHashMap);
                for (Order order : orders) {
                    String oldtoken = order.getOldtoken();
                    String buytime = order.getBuytime();
                    invite.setOldtoken(oldtoken);
                    invite.setToken(token);
                    invite.setBuytime(buytime);
                    invite.setTransaction_id(order.getTransaction_id());
                    inviteService.insert(invite);
                }

                System.out.println("结束=============================");

                /**此处添加自己的业务逻辑代码end**/
                //通知微信服务器已经支付成功
                resXml = "" + ""
                        + "" + " ";
            }
        }else{
            resXml = "" + ""
                    + "" + " ";
        }

        System.out.println(resXml);
        System.out.println("微信支付回调数据结束");

        BufferedOutputStream out = new BufferedOutputStream(
                response.getOutputStream());
        out.write(resXml.getBytes());
        out.flush();
        out.close();
        Map maps = PayUtil.doXMLParse(resXml);
        String returnCodes = (String) maps.get("return_code");
        return  returnCodes;
    }
}

工具类仅展示获取IP地址

package com.lbm.utils;

import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletRequest;

public class IpUtils {
    /**
     * IpUtils工具类方法
     * 获取真实的ip地址
     * @param request
     * @return
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("X-Forwarded-For");
        if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
            //多次反向代理后会有多个ip值，第一个ip才是真实ip
            int index = ip.indexOf(",");
            if(index != -1){
                return ip.substring(0,index);
            }else{
                return ip;
            }
        }
        ip = request.getHeader("X-Real-IP");
        if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
            return ip;
        }
        return request.getRemoteAddr();
    }
}