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

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 * or more contributor license agreements.  See the NOTICE file
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 * 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
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 * <http://www.apache.org/>.
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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 certs
        SSLContext sslcontext = SSLContexts.custom()
                .loadKeyMaterial(keyStore, "10016225".toCharArray())
                .build();
        // Allow TLSv1 protocol only
        SSLConnectionSocketFactory 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 certs
        SSLContext sslcontext = SSLContexts.custom()
                .loadKeyMaterial(keyStore, WxPayConfig.MCH_ID.toCharArray())
                .build();
        // Allow TLSv1 protocol only
        SSLConnectionSocketFactory 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();
            return 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