微信支付/

 微信支付准备工作

3.2.1 如何保证数据安全？

完成微信支付有两个关键的步骤：

第一个就是需要在商户系统当中调用微信后台的一个下单接口，就是生成预支付交易单。

第二个就是支付成功之后微信后台会给推送消息。

这两个接口数据的安全性，要求其实是非常高的。

解决：微信提供的方式就是对数据进行加密、解密、签名多种方式。要完成数据加密解密，需要提前准备相应的一些文件，其实就是一些证书。

获取微信支付平台证书、商户私钥文件：

12

配置属性类

package com.sky.properties;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties(prefix = "sky.wechat")
@Data
public class WeChatProperties {

    private String appid; //小程序的appid
    private String secret; //小程序的秘钥
    private String mchid; //商户号
    private String mchSerialNo; //商户API证书的证书序列号
    private String privateKeyFilePath; //商户私钥文件
    private String apiV3Key; //证书解密的密钥
    private String weChatPayCertFilePath; //平台证书
    private String notifyUrl; //支付成功的回调地址   访问自己的后台来提醒后台支付成功
    private String refundNotifyUrl; //退款成功的回调地址

}

在application中配置

sky:
  wechat:
    appid: ${sky.wechat.appid}
    secret: ${sky.wechat.secret}
    mchid : ${sky.wechat.mchid}
    mchSerialNo: ${sky.wechat.mchSerialNo}
    privateKeyFilePath: ${sky.wechat.privateKeyFilePath}
    apiV3Key: ${sky.wechat.apiV3Key}
    weChatPayCertFilePath: ${sky.wechat.weChatPayCertFilePath}
    notifyUrl: ${sky.wechat.notifyUrl}
    refundNotifyUrl: ${sky.wechat.refundNotifyUrl}

微信支付工具类

package com.sky.utils;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.sky.properties.WeChatProperties;
import com.wechat.pay.contrib.apache.httpclient.WechatPayHttpClientBuilder;
import com.wechat.pay.contrib.apache.httpclient.util.PemUtil;
import org.apache.commons.lang.RandomStringUtils;
import org.apache.http.HttpHeaders;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.math.BigDecimal;
import java.security.PrivateKey;
import java.security.Signature;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Base64;
import java.util.List;

/**
 * 微信支付工具类
 */
@Component
public class WeChatPayUtil {

    //微信支付下单接口地址
    public static final String JSAPI = "https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi";

    //申请退款接口地址
    public static final String REFUNDS = "https://api.mch.weixin.qq.com/v3/refund/domestic/refunds";

    @Autowired
    private WeChatProperties weChatProperties;

    /**
     * 获取调用微信接口的客户端工具对象
     *
     * @return
     */
    private CloseableHttpClient getClient() {
        PrivateKey merchantPrivateKey = null;
        try {
            //merchantPrivateKey商户API私钥，如何加载商户API私钥请看常见问题
            merchantPrivateKey = PemUtil.loadPrivateKey(new FileInputStream(new File(weChatProperties.getPrivateKeyFilePath())));
            //加载平台证书文件
            X509Certificate x509Certificate = PemUtil.loadCertificate(new FileInputStream(new File(weChatProperties.getWeChatPayCertFilePath())));
            //wechatPayCertificates微信支付平台证书列表。你也可以使用后面章节提到的“定时更新平台证书功能”，而不需要关心平台证书的来龙去脉
            List wechatPayCertificates = Arrays.asList(x509Certificate);

            WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create()
                    .withMerchant(weChatProperties.getMchid(), weChatProperties.getMchSerialNo(), merchantPrivateKey)
                    .withWechatPay(wechatPayCertificates);

            // 通过WechatPayHttpClientBuilder构造的HttpClient，会自动的处理签名和验签
            CloseableHttpClient httpClient = builder.build();
            return httpClient;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 发送post方式请求
     *
     * @param url
     * @param body
     * @return
     */
    private String post(String url, String body) throws Exception {
        CloseableHttpClient httpClient = getClient();

        HttpPost httpPost = new HttpPost(url);
        httpPost.addHeader(HttpHeaders.ACCEPT, ContentType.APPLICATION_JSON.toString());
        httpPost.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.toString());
        httpPost.addHeader("Wechatpay-Serial", weChatProperties.getMchSerialNo());
        httpPost.setEntity(new StringEntity(body, "UTF-8"));

        CloseableHttpResponse response = httpClient.execute(httpPost);
        try {
            String bodyAsString = EntityUtils.toString(response.getEntity());
            return bodyAsString;
        } finally {
            httpClient.close();
            response.close();
        }
    }

    /**
     * 发送get方式请求
     *
     * @param url
     * @return
     */
    private String get(String url) throws Exception {
        CloseableHttpClient httpClient = getClient();

        HttpGet httpGet = new HttpGet(url);
        httpGet.addHeader(HttpHeaders.ACCEPT, ContentType.APPLICATION_JSON.toString());
        httpGet.addHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.toString());
        httpGet.addHeader("Wechatpay-Serial", weChatProperties.getMchSerialNo());

        CloseableHttpResponse response = httpClient.execute(httpGet);
        try {
            String bodyAsString = EntityUtils.toString(response.getEntity());
            return bodyAsString;
        } finally {
            httpClient.close();
            response.close();
        }
    }

    /**
     * jsapi下单
     *
     * @param orderNum    商户订单号
     * @param total       总金额
     * @param description 商品描述
     * @param openid      微信用户的openid
     * @return
     */
    private String jsapi(String orderNum, BigDecimal total, String description, String openid) throws Exception {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("appid", weChatProperties.getAppid());
        jsonObject.put("mchid", weChatProperties.getMchid());
        jsonObject.put("description", description);
        jsonObject.put("out_trade_no", orderNum);
        jsonObject.put("notify_url", weChatProperties.getNotifyUrl());

        JSONObject amount = new JSONObject();
        amount.put("total", total.multiply(new BigDecimal(100)).setScale(2, BigDecimal.ROUND_HALF_UP).intValue());
        amount.put("currency", "CNY");

        jsonObject.put("amount", amount);

        JSONObject payer = new JSONObject();
        payer.put("openid", openid);

        jsonObject.put("payer", payer);

        String body = jsonObject.toJSONString();
        return post(JSAPI, body);
    }

    /**
     * 小程序支付
     *
     * @param orderNum    商户订单号
     * @param total       金额，单位 元
     * @param description 商品描述
     * @param openid      微信用户的openid
     * @return
     */
    public JSONObject pay(String orderNum, BigDecimal total, String description, String openid) throws Exception {
        //统一下单，生成预支付交易单
        String bodyAsString = jsapi(orderNum, total, description, openid);
        //解析返回结果
        JSONObject jsonObject = JSON.parseObject(bodyAsString);
        System.out.println(jsonObject);

        String prepayId = jsonObject.getString("prepay_id");
        if (prepayId != null) {
            String timeStamp = String.valueOf(System.currentTimeMillis() / 1000);
            String nonceStr = RandomStringUtils.randomNumeric(32);
            ArrayList