微信小程序 支付后台java实现实例

微信小程序 支付后台java实现实例

前言：

前些天使用 leancloud 云引擎写了个小程序的支付相关 以前只做过 app 支付 这次在小程序支付爬了两天的坑 把代码也分享出来

支付流程:

1.小程序前端获取微信 openid 以及订单号 传给后台
2,后台根据 openid 和订单号进行签名 post 微信统一下单接口
3.后台获取微信返回的xml字符串 解析 二次签名以后返回给前端
4.前端调起支付微信支付 api

先看支付函数:

//获取支付信息
  @enginefunction("getpayinformation")
  public static map<string, object> getpayinformation(
      @enginefunctionparam("orderid") string orderid
  ) throws avexception, unsupportedencodingexception, documentexception {
    map<string, object> reqmap = new treemap<string, object>(
        new comparator<string>() {
          public int compare(string obj1, string obj2) {
            // 升序排序
            return obj1.compareto(obj2);
          }
        });
    if (avuser.getcurrentuser() != null) {
      string authdatajson = jsonarray.tojsonstring(avuser.getcurrentuser().get("authdata"));
      jsonobject jsonobject = json.parseobject(authdatajson);
      jsonobject.get("lc_weapp");
      jsonobject j2 = json.parseobject(jsonobject.get("lc_weapp").tostring());
      string openid = (string) j2.get("openid");

      avquery<order> query = avobject.getquery(order.class);
      order order = query.get(orderid);
      reqmap.put("appid", system.getenv("appid"));
      reqmap.put("mch_id", system.getenv("mch_id"));
      reqmap.put("nonce_str", wxpayutil.getnonce_str());
      reqmap.put("body", new string(order.getdisheslist().tostring().getbytes("utf-8")));
      reqmap.put("openid", openid);
      reqmap.put("out_trade_no", order.getobjectid());
      reqmap.put("total_fee", 1); //订单总金额，单位为分
      reqmap.put("spbill_create_ip", "192.168.0.1"); //用户端ip
      reqmap.put("notify_url", system.getenv("notify_url")); //通知地址
      reqmap.put("trade_type", system.getenv("trade_type")); //trade_type=jsapi时（即公众号支付），此参数必传，此参数为微信用户在商户对应appid下的唯一标识
      string reqstr = wxpayutil.map2xml(reqmap);
      string resultxml = httprequest.sendpost(reqstr);
      system.out.println("微信请求返回:" + resultxml);
      //解析微信返回串 如果状态成功 则返回给前端
      if (wxpayutil.getreturncode(resultxml) != null && wxpayutil.getreturncode(resultxml).equals("success")) {
        //成功
        map<string, object> resultmap = new treemap<>(
            new comparator<string>() {
              public int compare(string obj1, string obj2) {
                // 升序排序
                return obj1.compareto(obj2);
              }
            });
        resultmap.put("appid", system.getenv("appid"));
        resultmap.put("noncestr", wxpayutil.getnoncestr(resultxml));//解析随机字符串
        resultmap.put("package", "prepay_id=" + wxpayutil.getprepayid(resultxml));
        resultmap.put("signtype", "md5");
        resultmap.put("timestamp", string.valueof((system.currenttimemillis() / 1000)));//时间戳
        string paysign = wxpayutil.getsign(resultmap);
        resultmap.put("paysign", paysign);
        return resultmap;
      } else {
        throw new avexception(999, "微信请求支付失败");
      }
    } else {
      throw new avexception(98, "当前未登录用户");
    }
  }

其中appid和mch_id可以用系统常量

ps:这里注意一个坑

二次签名的时候使用 appid noncestr package signtype timestamp 这五个key生成签名(这里无视微信官方文档 以及注意 appid 的大小写)

前端调起api支付时 按照官方文档就可以

网络请求类:

httprequest

import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstreamreader;
import java.io.printwriter;
import java.net.url;
import java.net.urlconnection;
import java.util.list;
import java.util.map;

public class httprequest {
  /**
   * 向指定url发送get方法的请求
   *
   * @param url  发送请求的url
   * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
   * @return url 所代表远程资源的响应结果
   */
  public static string sendget(string url, string param) {
    string result = "";
    bufferedreader in = null;
    try {
      string urlnamestring = url + "?" + param;
      url realurl = new url(urlnamestring);
      // 打开和url之间的连接
      urlconnection connection = realurl.openconnection();
      // 设置通用的请求属性
      connection.setrequestproperty("accept", "*/*");
      connection.setrequestproperty("connection", "keep-alive");
      connection.setrequestproperty("user-agent",
          "mozilla/4.0 (compatible; msie 6.0; windows nt 5.1;sv1)");
      // 建立实际的连接
      connection.connect();
      // 获取所有响应头字段
      map<string, list<string>> map = connection.getheaderfields();
      // 遍历所有的响应头字段
      for (string key : map.keyset()) {
        system.out.println(key + "--->" + map.get(key));
      }
      // 定义 bufferedreader输入流来读取url的响应
      in = new bufferedreader(new inputstreamreader(
          connection.getinputstream()));
      string line;
      while ((line = in.readline()) != null) {
        result += line;
      }
    } catch (exception e) {
      system.out.println("发送get请求出现异常！" + e);
      e.printstacktrace();
    }
    // 使用finally块来关闭输入流
    finally {
      try {
        if (in != null) {
          in.close();
        }
      } catch (exception e2) {
        e2.printstacktrace();
      }
    }
    return result;
  }

  /**
   * 向指定 url 发送post方法的请求
   *
   * @param url  发送请求的 url
   * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
   * @return 所代表远程资源的响应结果
   */
  public static string sendpost(string param) {
    printwriter out = null;
    bufferedreader in = null;
    string result = "";
    try {
      url realurl = new url("https://api.mch.weixin.qq.com/pay/unifiedorder");
      // 打开和url之间的连接
      urlconnection conn = realurl.openconnection();
      // 设置通用的请求属性
      conn.setrequestproperty("accept", "*/*");
      conn.setrequestproperty("connection", "keep-alive");
      conn.setrequestproperty("user-agent", "mozilla/4.0 (compatible; msie 6.0; windows nt 5.1;sv1)");
//      conn.setrequestproperty("pragma:", "no-cache");
//      conn.setrequestproperty("cache-control", "no-cache");
//      conn.setrequestproperty("content-type", "text/xml;charset=utf-8");
      // 发送post请求必须设置如下两行
      conn.setdooutput(true);
      conn.setdoinput(true);
      // 获取urlconnection对象对应的输出流
      out = new printwriter(conn.getoutputstream());
      // 发送请求参数
      out.print(param);
      // flush输出流的缓冲
      out.flush();
      // 定义bufferedreader输入流来读取url的响应
      in = new bufferedreader(
          new inputstreamreader(conn.getinputstream()));
      string line;
      while ((line = in.readline()) != null) {
        result += line;
      }
    } catch (exception e) {
      system.out.println("发送 post 请求出现异常！" + e);
      e.printstacktrace();
    }
    //使用finally块来关闭输出流、输入流
    finally {
      try {
        if (out != null) {
          out.close();
        }
        if (in != null) {
          in.close();
        }
      } catch (ioexception ex) {
        ex.printstacktrace();
      }
    }
    return result;
  }
}

xml解析工具类

wxpayutil

import org.w3c.dom.nodelist;

import javax.xml.parsers.documentbuilder;
import javax.xml.parsers.documentbuilderfactory;
import java.io.bytearrayinputstream;
import java.io.inputstream;
import java.io.unsupportedencodingexception;
import java.util.map;
import java.util.random;


public class wxpayutil {

  //生成随机字符串
  public static string getnonce_str() {
    string base = "abcdefghijklmnopqrstuvwxyz0123456789";
    random random = new random();
    stringbuilder sb = new stringbuilder();
    for (int i = 0; i < 15; i++) {
      int number = random.nextint(base.length());
      sb.append(base.charat(number));
    }
    return sb.tostring();
  }

  //map转xml 加上签名信息
  public static string map2xml(map<string, object> map) throws unsupportedencodingexception {
    stringbuffer sb = new stringbuffer();
    stringbuilder sb2 = new stringbuilder();
    sb2.append("<xml>");
    for (string key : map.keyset()) {
      sb.append(key);
      sb.append('=');
      sb.append(map.get(key));
      sb.append('&');
      // sb2是用来做请求的xml参数
      sb2.append("<" + key + ">");
//      sb2.append("<![cdata[" + map.get(key) + "]]>");
      sb2.append(map.get(key));
      sb2.append("</" + key + ">");
    }
    sb.append(system.getenv("signkey"));
    string sign = md5.getmessagedigest(sb.tostring().getbytes()).touppercase();
    sb2.append("<sign>");
    sb2.append(sign);
    sb2.append("</sign>");
    sb2.append("</xml>");
    return sb2.tostring();
  }

  //解析微信返回return_code success或file
  //根据微信返回resultxml再次生成签名
  public static string getsign(map<string, object> map) {
    stringbuffer sb = new stringbuffer();
    for (string key : map.keyset()) {
      sb.append(key);
      sb.append('=');
      sb.append(map.get(key));
      sb.append('&');
    }
    sb.append(system.getenv("signkey"));
    system.out.println("第二次签名内容:" + sb);
    system.out.println("第二次签名sing:" + md5.getmessagedigest(sb.tostring().getbytes()).touppercase());
    return md5.getmessagedigest(sb.tostring().getbytes()).touppercase();
  }

  //解析微信返回return_code success或file
  public static string getreturncode(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("return_code");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }

  //解析微信返回return_msg
  public static string getreturn_msg(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("return_msg");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }

  //解析微信返回appid
  public static string getappid(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("appid");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }

  //解析微信返回mch_id
  public static string getmchid(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("mch_id");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }

  //解析微信返回nonce_str
  public static string getnoncestr(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("nonce_str");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }

  //解析微信返回prepay_id
  public static string getprepayid(string resultxml) {
    string noncestr;
    documentbuilderfactory dbf = documentbuilderfactory.newinstance();
    documentbuilder builder;
    try {
      builder = dbf.newdocumentbuilder();
      inputstream inputstream = new bytearrayinputstream(resultxml.getbytes());
      org.w3c.dom.document doc = builder.parse(inputstream); //
      // 下面开始读取
      org.w3c.dom.element root = doc.getdocumentelement(); // 获取根元素
      nodelist nl = root.getelementsbytagname("prepay_id");
      org.w3c.dom.element el = (org.w3c.dom.element) nl.item(0);
      org.w3c.dom.node nd = el.getfirstchild();
      noncestr = nd.getnodevalue();
      return noncestr;
    } catch (exception e) {
      e.printstacktrace();
      return null;
    }
  }


}

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