微信小程序支付开发之申请退款

微信小程序支付跟微信公众号支付类似，这里不另做记录，如果没有开发过支付，可以查看我关于微信支付的文章

重点记录微信小程序申请退款开发过程中遇到一些坑。

退款接口比支付接口接口多了一个 双向证书

证书介绍：https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=4_3

由于这里是Java开发，所有下载apiclient_cert.p12文件，下面是官方给的demo

/* * ==================================================================== * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements.  See the NOTICE file * distributed with this work for additional information * regarding copyright ownership.  The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License.  You may obtain a copy of the License at * *http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied.  See the License for the * specific language goveing permissions and limitations * under the License. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation.  For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */package httpstest;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.InputStreamReader;import java.security.KeyStore;import javax.net.ssl.SSLContext;import org.apache.http.HttpEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.conn.ssl.SSLContexts;import org.apache.http.conn.ssl.SSLConnectionSocketFactory;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.util.EntityUtils;/** * This example demonstrates how to create secure connections with a custom SSL * context. */public class ClientCustomSSL {public final static void main(String[] args) throws Exception {KeyStore keyStore  = KeyStore.getInstance("PKCS12");FileInputStream instream = new FileInputStream(new File("D:/10016225.p12"));try {keyStore.load(instream, "10016225".toCharArray());} finally {instream.close();}// Trust own CA and all self-signed certsSSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore, "10016225".toCharArray()).build();// Allow TLSv1 protocol onlySSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext,new String[] { "TLSv1" },null,SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();try {HttpGet httpget = new HttpGet("https://api.mch.weixin.qq.com/secapi/pay/refund");System.out.println("executing request" + httpget.getRequestLine());CloseableHttpResponse response = httpclient.execute(httpget);try {HttpEntity entity = response.getEntity();System.out.println("----------------------------------------");System.out.println(response.getStatusLine());if (entity != null) {System.out.println("Response content length: " + entity.getContentLength());BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(entity.getContent()));String text;while ((text = bufferedReader.readLine()) != null) {System.out.println(text);}}EntityUtils.consume(entity);} finally {response.close();}} finally {httpclient.close();}}}

在上面代码进行微调

private static void ClientCustomSSL(String xmlStr) throws  Exception{KeyStore keyStore  = KeyStore.getInstance("PKCS12");FileInputStream instream = new FileInputStream(new File("D:/apiclient_cert.p12"));try {keyStore.load(instream, WxPayConfig.MCH_ID.toCharArray());} finally {instream.close();}// Trust own CA and all self-signed certsSSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore, WxPayConfig.MCH_ID.toCharArray()).build();// Allow TLSv1 protocol onlySSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext,new String[] { "TLSv1" },null,SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();try {HttpPost httpPost = new HttpPost("https://api.mch.weixin.qq.com/secapi/pay/refund");StringEntity entityStr = new StringEntity(xmlStr);entityStr.setContentType("text/xml");System.out.println("entityStr--------------"+entityStr);httpPost.setEntity(entityStr);CloseableHttpResponse response = httpclient.execute(httpPost);try {HttpEntity entity = response.getEntity();System.out.println("----------------------------------------");System.out.println(response.getStatusLine());if (entity != null) {System.out.println("Response content length: " + entity.getContentLength());BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(entity.getContent()));String text;while ((text = bufferedReader.readLine()) != null) {System.out.println(text);}}EntityUtils.consume(entity);} finally {response.close();}} finally {httpclient.close();retu null;}}

参数 String xmlStr 是传入的封装好的xml字符串（封装方法在我微信支付开发的文章里面有）
然后测试结果

这里面签名有个隐藏的坑，就是请求字段，和mic_id都正确，微信签名验证也正确，请求就是报签名错误
原因是我的退款原因（refund_desc）参数是中文的，把它调成英文的

不得不说微信支付开发文档很坑