02-微信支付

官网地址：https://pay.weixin.qq.com/static/applyment_guide/applyment_index.shtml

API文档：https://pay.weixin.qq.com/wiki/doc/apiv3/wxpay/pages/api.shtml

1. 封装 XML 操作

Dom4J、Sax、pull、jackson

Dom4J解析XML工具类

2. 封装二维码操作

QrCodeUtil-二维码生成与解析

3. 微信支付 Demo

基于 微信开发文档 V2 版

准备工具：xml生成和解析、网络请求、微信支付的API、二维码、WebSocket（Socket、Nio、Netty）

网络请求，服务端请求第三方接口：
解决方案：
1.HttpURLConnection
2.HttpClient
3.OKhttp

3.1 HttpUtil

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

public class HttpUtil {
    //post请求
    public static String postXml(String url, String xml) {
        //1、实例化请求对象
        HttpPost post = new HttpPost(url);
        //HttpGet;
        //HttpPut;
        //HttpDelete;
        try {
            //2、实例化请求实体
            HttpEntity entity = new StringEntity(xml, "UTF-8");
            post.setEntity(entity);
            //3、实例化客户端对象
            HttpClient client = HttpClientBuilder.create().build();
            //4、执行请求 获取响应结果
            HttpResponse response = client.execute(post);
            //5、验证http状态码
            if (response.getStatusLine().getStatusCode() == 200) {
                //6、返回响应结果
                return EntityUtils.toString(response.getEntity());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

3.2 MD5Util

MD5加密和微信的签名算法：

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.MessageDigest;

public class MD5Util {
    /**
     * 字节数组转16进制字符串
     *
     * @param b
     * @return
     */
    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /**
     * 字节转16进制字符串
     *
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n += 256;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * MD5 加密
     *
     * @param origin
     * @param charsetname
     * @return
     */
    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname)) {
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            } else {
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
            }
        } catch (Exception exception) {
        }
        return resultString;
    }

    private static final String hexDigits[] = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"
    };

    public static String UrlEncode(String src) throws
            UnsupportedEncodingException {
        return URLEncoder.encode(src, "UTF-8").replace("+", "%20");
    }
}

3.3 封装工具类

import org.springframework.util.StringUtils;

import java.util.*;

public class WxPayUtil {
    /**
     * 微信相关配置
     */
    public static String APP_ID = "（appid）";
    public static String MCH_ID = "（mchid）";
    public static String API_KEY = "（api key）";
    public static String NOTIFY_URL = "（notify url）"; // eg: http://localhost:8080/
    /**
     * 常用API接口
     */
    public static String WXPAY_UNIFIE = "https://api.mch.weixin.qq.com/pay/unifiedorder";
    public static String WXPAY_QUERY = "https://api.mch.weixin.qq.com/pay/orderquery";
    public static String WXPAY_CLOSE = "https://api.mch.weixin.qq.com/pay/closeorder";
    public static String WXPAY_BILL = "https://api.mch.weixin.qq.com/pay/downloadbill";

    private static TreeMap<String, String> initParam() {
        TreeMap<String, String> map = new TreeMap<>();
        map.put("appid", APP_ID);
        map.put("mch_id", MCH_ID);
        map.put("nonce_str", UUID.randomUUID().toString().replaceAll("-", ""));
        return map;
    }

    private static String createSign(SortedMap<String, String> packageParams) {
        StringBuffer sb = new StringBuffer();
        Set<Map.Entry<String, String>> es = packageParams.entrySet();
        for (Map.Entry<String, String> entry : es) {
            String k = entry.getKey();
            String v = entry.getValue();
            if (null != v && !"".equals(v) && !"sign".equals(k) &&
                    !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        sb.append("key=" + API_KEY);
        return MD5Util.MD5Encode(sb.toString(), "UTF-8").toUpperCase();
    }

    /**
     * 生成预支付连接
     */
    public static String wxpayCreate(PayDto dto) {
        TreeMap<String, String> map = initParam();
        map.put("body", dto.getOrderdes());
        map.put("out_trade_no", dto.getOid());
        map.put("total_fee", dto.getPrice() + "");
        //map.put("total_fee",1);
        map.put("spbill_create_ip", "117.159.15.221");
        map.put("notify_url", NOTIFY_URL);
        map.put("trade_type", "NATIVE");
        map.put("sign", createSign(map));
        String requestXml = XmlUtil.createXML(map);
        System.err.println("------->" + requestXml);
        String responseXml = HttpUtil.postXml(WXPAY_UNIFIE, requestXml);
        System.err.println("------->" + responseXml);
        if (!StringUtils.isEmpty(responseXml)) {
            Map<String, String> res = XmlUtil.parseXml(responseXml);
            if (res != null) {
                return res.get("code_url");
            }
        }
        return null;
    }

    /**
     * 查询支付状态
     */
    public static String wxpayQuery(String oid) {
        TreeMap<String, String> map = initParam();
        map.put("out_trade_no", oid);
        map.put("sign", createSign(map));
        String requestXml = XmlUtil.createXML(map);
        String responseXml = HttpUtil.postXml(WXPAY_QUERY, requestXml);
        if (!StringUtils.isEmpty(responseXml)) {
            Map<String, String> res = XmlUtil.parseXml(responseXml);
            //SUCCESS—支付成功
            //REFUND—转入退款
            //NOTPAY—未支付
            //CLOSED—已关闭
            //REVOKED—已撤销（付款码支付）
            //USERPAYING--用户支付中（付款码支付）
            //PAYERROR--支付失败(其他原因，如银行返回失败)
            if (res != null) {
                return res.get("trade_state");
            }
        }
        return null;
    }

    /**
     * 关闭支付
     */
    public static String wxpayClose(String oid) {
        TreeMap<String, String> map = initParam();
        map.put("out_trade_no", oid);
        map.put("sign", createSign(map));
        String requestXml = XmlUtil.createXML(map);
        String responseXml = HttpUtil.postXml(WXPAY_CLOSE, requestXml);
        if (!StringUtils.isEmpty(responseXml)) {
            Map<String, String> res = XmlUtil.parseXml(responseXml);
            //SUCCESS—支付成功
            //REFUND—转入退款
            //NOTPAY—未支付
            //CLOSED—已关闭
            //REVOKED—已撤销（付款码支付）
            //USERPAYING--用户支付中（付款码支付）
            //PAYERROR--支付失败(其他原因，如银行返回失败)
            if (res != null) {
                return res.get("result_code");
            }
        }
        return null;
    }
}

3.4 封装接口实现

// 接口
public interface WxPayService {
    R<String> createPay(PayDto dto);
    R<String> queryPay(String oid);
    R<String> closePay(String oid);
}

// 实现类
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import java.util.Base64;

@Service
public class WxPayServiceImpl implements WxPayService {

    @Override
    public R<String> createPay(PayDto dto) {
        String qrcode = WxPayUtil.wxpay_create(dto);
        if (!StringUtils.isEmpty(qrcode)) {
            //生成二维码
            return R.ok("http://localhost:8085/api/qrcode/payqrcode/" + Base64.getUrlEncoder().encodeToString(qrcode.getBytes()));
        }
        return R.error();
    }

    @Override
    public R<String> queryPay(String oid) {
        return R.ok(WxPayUtil.wxpay_query(oid));
    }

    @Override
    public R<String> closePay(String oid) {
        return R.ok(WxPayUtil.wxpay_close(oid));
    }
}