微信小程序+微信支付+java后台（springboot）使用的是微信官方支付SDK（附代码）

刚开始做，网上找了很多，下载了三个demo，最后发现，这玩意还是需要个干货！

讲重点：

1.下载微信官方的SDK

https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=11_1

选择下载java版本最佳实践。

2.将以下文件拷到你的项目中

3.在同文件夹下创建此继承类

package com.***.utils.wx;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

/**
 * @De ion: 微信支付配置类
 * @Author: hm
 * @CreateDate: 2018/12/10 17:19.
 * @UpdateDate: 2018/12/10 17:19.
 * @Version: 1.0
 */
public class MyConfig extends WXPayConfig {

    private byte[] certData;
    public MyConfig() throws Exception {
//        String certPath = \"classpath:apiclient_cert.p12\";
//        File file = new File(certPath);
//        InputStream certStream = new FileInputStream(file);
//        this.certData = new byte[(int) file.length()];
//        certStream.read(this.certData);
//        certStream.close();
    }

    @Override
    public String getAppID() {
        return \"你的appid\";
    }

    @Override
    public String getMchID() {
        return \"你的商户id\";
    }

    @Override
    public String getKey() {
        return \"你的商户api安全key，在商户平台api安全目录下可设置\";
    }

    @Override
    public InputStream getCertStream() {
        ByteArrayInputStream certBis = new ByteArrayInputStream(this.certData);
        return certBis;
    }

    @Override
    public int getHttpConnectTimeoutMs() {
        return 8000;
    }

    @Override
    public int getHttpReadTimeoutMs() {
        return 10000;
    }

    @Override
    IWXPayDomain getWXPayDomain() {
        return new IWXPayDomain() {
            @Override
            public void report(String domain, long elapsedTimeMillis, Exception ex) {
            }

            @Override
            public DomainInfo getDomain(WXPayConfig config) {
                return new DomainInfo(\"api.mch.weixin.qq.com\", false);
            }
        };
    }
}

4.java后台的调用统一下单接口类

/**
     * 微信统一下单接口
     * @return
     */
    @RequestMapping(value = \"/doUnifiedOrder\", method = RequestMethod.POST)
    public  Response<Map> doUnifiedOrder(@RequestBody BaesRequest<LicensePlate>  Request) {
         Response<Map> response = new  Response<>();
        Map resultMap=new HashMap();
        String openid =  Request.getRequestData().getOpenId();
        MyConfig config = null;
        WXPay wxpay =null;
        try {
            config = new MyConfig();
            wxpay= new WXPay(config);
        } catch (Exception e) {
            e.printStackTrace();
        }
        //生成的随机字符串
        String nonce_str = WXPayUtil.generateNonceStr();
        //获取客户端的ip地址
        //获取本机的ip地址
        InetAddress addr = null;
        try {
            addr = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        String spbill_create_ip = addr.getHostAddress();
        //支付金额，需要转成字符串类型，否则后面的签名会失败
        int  total_fee=1;
        //商品描述
        String body = \"车费支付\";
        //商户订单号
        String out_trade_no= WXPayUtil.generateNonceStr();
        //统一下单接口参数
        HashMap<String, String> data = new HashMap<String, String>();
        data.put(\"appid\", appid);
        data.put(\"mch_id\", mch_id);
        data.put(\"nonce_str\", nonce_str);
        data.put(\"body\", body);
        data.put(\"out_trade_no\",out_trade_no);
        data.put(\"total_fee\", String.valueOf(total_fee));
        data.put(\"spbill_create_ip\", spbill_create_ip);
        data.put(\"notify_url\", notify_url);
        data.put(\"trade_type\",TRADETYPE);
        data.put(\"openid\", openid);
        try {
            Map<String, String> rMap = wxpay.unifiedOrder(data);
            System.out.println(\"统一下单接口返回: \" + rMap);
            String return_code = (String) rMap.get(\"return_code\");
            String result_code = (String) rMap.get(\"result_code\");
            String nonceStr = WXPayUtil.generateNonceStr();
            resultMap.put(\"nonceStr\", nonceStr);
            Long timeStamp = System.currentTimeMillis() / 1000;
            if (\"SUCCESS\".equals(return_code) && return_code.equals(result_code)) {
                String prepayid = rMap.get(\"prepay_id\");
                resultMap.put(\"package\", \"prepay_id=\"+prepayid);
                resultMap.put(\"signType\", \"MD5\");
                //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
                resultMap.put(\"timeStamp\", timeStamp + \"\");
                //再次签名，这个签名用于小程序端调用wx.requesetPayment方法
                resultMap.put(\"appId\",appid);
                String sign = WXPayUtil.generateSignature(resultMap, key);
                resultMap.put(\"paySign\", sign);
                System.out.println(\"生成的签名paySign : \"+ sign);
                response.setData(resultMap);
                return response;
            }else{
                return  response;
            }
        } catch (Exception e) {
            e.printStackTrace();
            return  response;
        }
    }

5.小程序端的支付请求

payNow: function() {
    var that = this;
    wx.request({
      url: app.data.requestUrl + \'weChatPay/doUnifiedOrder\',
      header: {
        \"Content-Type\": \"application/json;charset=UTF-8\"
      },
      data: {
        requestData: {
          openId: app.globalData.openId
        }
      },
      method: \'POST\',
      dataType: \'json\',
      responseType: \'text\',
      success: function(res) {
        console.log(\"服务端返回订单号\");
        var c=res.data;
        wx.requestPayment({
          timeStamp: res.data.data.timeStamp,
          nonceStr: res.data.data.nonceStr,
          package: res.data.data.package,
          signType: \'MD5\',
          paySign: res.data.data.paySign,
          success(res) {
            console.log(\"统一下单接口成功\");
          },
          fail(res) {
            console.log(\"统一下单接口失败\");
          }
        });
      },
      fail: function(res) {},
      complete: function(res) {},
    });
  }

6.超简单支付过程，只需要修改配置文件中你自己的appid等信息就可以使用了。文中没有java后台的业务逻辑，可以自己添加，这里主要实现支付功能。（为了隐私，截图中屏蔽了主体信息。）