Java语言开发微信小程序支付功能：

1.通过路径到官方下载Java的支付SDK。

2.下载后将pom文件中需要用到的jar包导入自己的项目中，将demo全部导入到自己的工具包中，需导入的demo如下图：

3.此时缺少IWXPayDomain与WXPayConfig抽象类的具体实现，新建WXPayDomainSimpleImpl与WXPayConfigImpl来分别实现抽象类，代码如下：

WXPayDomainSimpleImpl代码：

1 package com.karat.cn.util; 2 import org.apache.http.conn.ConnectTimeoutException; 3  4 import java.net.UnknownHostException; 5 import java.util.HashMap; 6 import java.util.Map; 7  8 /** 9  * Created by blaketang on 2017/6/16.10  */11 public class WXPayDomainSimpleImpl implements IWXPayDomain {12     private WXPayDomainSimpleImpl(){}13     private static class WxpayDomainHolder{14         private static IWXPayDomain holder = new WXPayDomainSimpleImpl();15     }16     public static IWXPayDomain instance(){17         return WxpayDomainHolder.holder;18     }19 20     public synchronized void report(final String domain, long elapsedTimeMillis, final Exception ex) {21         DomainStatics info = domainData.get(domain);22         if(info == null){23             info = new DomainStatics(domain);24             domainData.put(domain, info);25         }26 27         if(ex == null){ //success28             if(info.succCount >= 2){    //continue succ, clear error count29                 info.connectTimeoutCount = info.dnsErrorCount = info.otherErrorCount = 0;30             }else{31                 ++info.succCount;32             }33         }else if(ex instanceof ConnectTimeoutException){34             info.succCount = info.dnsErrorCount = 0;35             ++info.connectTimeoutCount;36         }else if(ex instanceof UnknownHostException){37             info.succCount = 0;38             ++info.dnsErrorCount;39         }else{40             info.succCount = 0;41             ++info.otherErrorCount;42         }43     }44 45     public synchronized DomainInfo getDomain(final WXPayConfig config) {46         DomainStatics primaryDomain = domainData.get(WXPayConstants.DOMAIN_API);47         if(primaryDomain == null ||48                 primaryDomain.isGood()) {49             return new DomainInfo(WXPayConstants.DOMAIN_API, true);50         }51 52         long now = System.currentTimeMillis();53         if(switchToAlternateDomainTime == 0){   //first switch54             switchToAlternateDomainTime = now;55             return new DomainInfo(WXPayConstants.DOMAIN_API2, false);56         }else if(now - switchToAlternateDomainTime < MIN_SWITCH_PRIMARY_MSEC){57             DomainStatics alternateDomain = domainData.get(WXPayConstants.DOMAIN_API2);58             if(alternateDomain == null ||59                 alternateDomain.isGood() ||60                 alternateDomain.badCount() < primaryDomain.badCount()){61                 return new DomainInfo(WXPayConstants.DOMAIN_API2, false);62             }else{63                 return new DomainInfo(WXPayConstants.DOMAIN_API, true);64             }65         }else{  //force switch back66             switchToAlternateDomainTime = 0;67             primaryDomain.resetCount();68             DomainStatics alternateDomain = domainData.get(WXPayConstants.DOMAIN_API2);69             if(alternateDomain != null)70                 alternateDomain.resetCount();71             return new DomainInfo(WXPayConstants.DOMAIN_API, true);72         }73     }74 75     static class DomainStatics {76         final String domain;77         int succCount = 0;78         int connectTimeoutCount = 0;79         int dnsErrorCount =0;80         int otherErrorCount = 0;81 82         DomainStatics(String domain) {83             this.domain = domain;84         }85         void resetCount(){86             succCount = connectTimeoutCount = dnsErrorCount = otherErrorCount = 0;87         }88         boolean isGood(){ return connectTimeoutCount <= 2 && dnsErrorCount <= 2; }89         int badCount(){90             return connectTimeoutCount + dnsErrorCount * 5 + otherErrorCount / 4;91         }92     }93     private final int MIN_SWITCH_PRIMARY_MSEC = 3 * 60 * 1000;  //3 minutes94     private long switchToAlternateDomainTime = 0;95     private Map
      
        domainData = new HashMap
       
        ();96 }
       
      

WXPayConfigImpl代码：

1 package com.karat.cn.util; 2  3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.ByteArrayInputStream; 6 import java.io.InputStream; 7  8  9 public class WXPayConfigImpl extends WXPayConfig{10 11     /**==========================================================================**/12     private byte[] certData;13     private static WXPayConfigImpl INSTANCE;14 15     private WXPayConfigImpl() throws Exception{16         String certPath = WXPayConfigImpl.class.getClassLoader().getResource("").getPath();17         File file = new File(certPath + "apiclient_cert.p12");18         InputStream certStream = new FileInputStream(file);19         this.certData = new byte[(int) file.length()];20         certStream.read(this.certData);21         certStream.close();22     }23 24     public static WXPayConfigImpl getInstance() throws Exception{25         if (INSTANCE == null) {26             synchronized (WXPayConfigImpl.class) {27                 if (INSTANCE == null) {28                     INSTANCE = new WXPayConfigImpl();29                 }30             }31         }32         return INSTANCE;33     }34     35     /**==========================================================================**/36     @Override37     public String getAppID() {38         // TODO Auto-generated method stub39         return "小程序AppId";40     }41 42     @Override43     public String getMchID() {44         // TODO Auto-generated method stub45         return "商户号";46     }47 48     @Override49     public String getKey() {50         // TODO Auto-generated method stub51         return "商户密钥";52     }53 54     @Override55     public InputStream getCertStream() {56         // TODO Auto-generated method stub57         ByteArrayInputStream certBis;58         certBis = new ByteArrayInputStream(this.certData);59         return certBis;60     }61 62     @Override63     public IWXPayDomain getWXPayDomain() {64         // TODO Auto-generated method stub65         return WXPayDomainSimpleImpl.instance();66     }67 68 }

4.向WXPayConstants.java中添加常量：

1 public static final String TRANSFERS_URL_SUFFIX = "/mmpaymkttransfers/promotion/transfers";2 public static final String SANDBOX_SENDREDPACK_URL_SUFFIX = "/sandboxnew/mmpaymkttransfers/sendredpack";3 public static final String SANDBOX_TRANSFERS_URL_SUFFIX = "/sandboxnew/mmpaymkttransfers/promotion/transfers";

5.向WXPay.java中添加如下代码：

1 /********************************************/ 2     // 企业付款 3     public String transfers(Map
      
        reqData) throws Exception { 4         return this.transfers(reqData, config.getHttpConnectTimeoutMs(), this.config.getHttpReadTimeoutMs()); 5     } 6     public String transfers(Map
       
         reqData,  int connectTimeoutMs, int readTimeoutMs) throws Exception { 7         String url; 8         if (this.useSandbox) { 9             url = WXPayConstants.SANDBOX_TRANSFERS_URL_SUFFIX;10         }11         else {12             url = WXPayConstants.TRANSFERS_URL_SUFFIX;13         }14         return this.requestWithCert(url, this.transfersRequestData(reqData), connectTimeoutMs, readTimeoutMs);15     }16     // 企业付款17     public Map
        
          transfersRequestData(Map
         
           reqData) throws Exception {18         // 商户号绑定的appid(小程序的appid)19         reqData.put("mch_appid", config.getAppID());20         // 商户号21         reqData.put("mchid", config.getMchID());22         // 随机字符串23         reqData.put("nonce_str", WXPayUtil.generateUUID());24         reqData.put("sign", WXPayUtil.generateSignature(reqData, config.getKey(), this.signType));25         return reqData;26     }27     28     /********************************************/
         
        
       
      

6.创建订单表以及返回给小程序端的参数vo

1 package com.karat.cn.wxCommon;  2   3 import java.util.Map;  4   5 import org.springframework.data.annotation.Id;  6 import org.springframework.data.mongodb.core.index.Indexed;  7 import org.springframework.data.mongodb.core.mapping.Document;  8   9 /** 10  * 订单表 11  * @author 开发 12  * 13  */ 14 @Document(collection = "wxWithdrawOrder") 15 public class WxWithdrawOrder { 16     /** 17      * id 18      */ 19     @Id 20     private String id; 21     /** 22      * 会员id 23      */ 24     @Indexed 25     private String memberId; 26     /** 27      * 订单号 28      */ 29     @Indexed(unique = true) 30     private String orderNo; 31     /** 32      * 提现金额(分) 33      */ 34     private int money; 35     /** 36      * 提现时间 37      */ 38     private String createDate; 39     /** 40      * 订单状态(0:申请失败或异常 1:已申请成功) 41      */ 42     private String orderStatus; 43     /** 44      * 扩展 45      */ 46     private Map
      
        remark; 47     /** 48      * 扩展2 49      */ 50     private String remark2; 51      52      53     public String getId() { 54         return id; 55     } 56     public void setId(String id) { 57         this.id = id; 58     } 59     public String getMemberId() { 60         return memberId; 61     } 62     public void setMemberId(String memberId) { 63         this.memberId = memberId; 64     } 65     public String getOrderNo() { 66         return orderNo; 67     } 68     public void setOrderNo(String orderNo) { 69         this.orderNo = orderNo; 70     } 71     public int getMoney() { 72         return money; 73     } 74     public void setMoney(int money) { 75         this.money = money; 76     } 77     public String getCreateDate() { 78         return createDate; 79     } 80     public void setCreateDate(String createDate) { 81         this.createDate = createDate; 82     } 83     public Map
       
         getRemark() { 84         return remark; 85     } 86     public void setRemark(Map
        
          remark) { 87         this.remark = remark; 88     } 89     public String getRemark2() { 90         return remark2; 91     } 92     public void setRemark2(String remark2) { 93         this.remark2 = remark2; 94     } 95     public String getOrderStatus() { 96         return orderStatus; 97     } 98     public void setOrderStatus(String orderStatus) { 99         this.orderStatus = orderStatus;100     }101 }
        
       
      

1 package com.karat.cn.vo; 2 /** 3  *  调用微信支付相关信息 4  * @author 开发 5  * 6  */ 7 public class VoUnifiedOrderWx { 8     // 时间戳 9     private String timeStamp;10     // 随机串11     private String nonceStr;12     // 数据包13     private String packageValue;14     // 签名15     private String sign;16     17     public String getTimeStamp() {18         return timeStamp;19     }20     public void setTimeStamp(String timeStamp) {21         this.timeStamp = timeStamp;22     }23     public String getNonceStr() {24         return nonceStr;25     }26     public void setNonceStr(String nonceStr) {27         this.nonceStr = nonceStr;28     }29     public String getPackageValue() {30         return packageValue;31     }32     public void setPackageValue(String packageValue) {33         this.packageValue = packageValue;34     }35     public String getSign() {36         return sign;37     }38     public void setSign(String sign) {39         this.sign = sign;40     }41     42 }

7.创建工具类(获取系统时间)

1 package com.karat.cn.wxCommon; 2  3 import java.text.ParseException; 4 import java.util.Date; 5  6 public class BaseToolsUtil { 7     /** 8      * 获取系统时间long 9      * 10      * @return11      * @throws ParseException12      */13     public static long systemtimeLong() {14         return new Date().getTime();15     }16 }

8.准备工作完毕，开始实现小程序支付，退款，提现功能。