微信小程序支付 java

话不多说，直接开撸。

支付流程步骤：

1）首先调用wx.login方法获取code，通过code获取openid；

2）java后台调用统一下单支付接口（这里会进行第一次签名），用来获取prepay_id；

3）java后台再次调用签名（这里会进行第二次签名），并返回支付需要用使用的参数；

4）小程序前端wx.requestPayment方法发起微信支付；

5）java后台接收来自微信服务器的通知并处理结果。

详细步骤可参考：https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_4&index=3

demo链接: https://pan.baidu.com/s/1v8QWUE1m2EnA4uAoAZtRRQ 密码: cgrt

 

一、获取openid，

这里的代码可以参考博主的另外一篇文章http://blog.csdn.net/zhourenfei17/article/details/77714600中的 3.1 代码模块，代码先贴上，如果了解更多点击链接查看

小程序端代码

 

wx.login({  
  success: function (res) {  
    var service_url = 'https://???/???/weixin/api/login?code=' + res.code;//需要将服务器域名添加到小程序的request合法域名中，而且必须是https开头  
    wx.request({  
      url: l,  
      data: {},  
      method: 'GET',  
      success: function (res) {  
        console.log(res);  
        if (res.data != null && res.data != undefined && res.data != '') {  
          wx.setStorageSync("openid", res.data.openid);//将获取的openid存到缓存中  
        }  
      }  
    });  
  }  
});  

 

 

 

 

 

 

java后端代码

/** 
  * 小程序后台登录，向微信平台发送获取access_token请求，并返回openId 
  * @param code 
  * @return 用户凭证 
  * @throws WeixinException 
  * @throws IOException  
  * @throws JsonMappingException  
  * @throws JsonParseException  
  */  
 @RequestMapping("login")  
 @ResponseBody  
 public Map login(String code, HttpServletRequest request) throws WeixinException, JsonParseException, JsonMappingException, IOException {  
     if (code == null || code.equals("")) {  
         throw new WeixinException("invalid null, code is null.");  
     }  
       
     Map ret = new HashMap();  
     //拼接参数  
     String param = "?grant_type=" + grant_type + "&appid=" + appid + "&secret=" + secret + "&js_code=" + code;  
       
     System.out.println("https://api.weixin.qq.com/sns/jscode2session" + param);  
       
     //创建请求对象  
     HttpsClient http = new HttpsClient();  
     //调用获取access_token接口  
     Response res = http.get("https://api.weixin.qq.com/sns/jscode2session" + param);  
     //根据请求结果判定，是否验证成功  
     JSONObject jsonObj = res.asJSONObject();  
     if (jsonObj != null) {  
         Object errcode = jsonObj.get("errcode");  
         if (errcode != null) {  
             //返回异常信息  
             throw new WeixinException(getCause(Integer.parseInt(errcode.toString())));  
         }  
           
         ObjectMapper mapper = new ObjectMapper();  
         OAuthJsToken oauthJsToken = mapper.readValue(jsonObj.toJSONString(),OAuthJsToken.class);  
         ret.put("openid", oauthJsToken.getOpenid());  
     }  
     return ret;  
 }  

二、小程序调用java后端接口，生成最终签名和相关参数小程序端代码：

var that = this;
      wx.request({
        url: service_url + 'wxPay',
        data: { },
        method: 'GET',
        success: function (res) {
          console.log(res);
           that.doWxPay(res.data);
        }
      });

java端代码：

​
​
/**
	 * @Description: 发起微信支付
	 * @param request
	 */
	public Map wxPay(Integer openid, HttpServletRequest request){
		try{
			//生成的随机字符串
			String nonce_str = StringUtils.getRandomStringByLength(32);
			//商品名称
			String body = "测试商品名称";
			//获取客户端的ip地址
			String spbill_create_ip = IpUtil.getIpAddr(request);
			
			//组装参数，用户生成统一下单接口的签名
			Map packageParams = new HashMap();
			packageParams.put("appid", WxPayConfig.appid);
			packageParams.put("mch_id", WxPayConfig.mch_id);
			packageParams.put("nonce_str", nonce_str);
			packageParams.put("body", body);
			packageParams.put("out_trade_no", "123456789");//商户订单号
			packageParams.put("total_fee", "1");//支付金额，这边需要转成字符串类型，否则后面的签名会失败
			packageParams.put("spbill_create_ip", spbill_create_ip);
			packageParams.put("notify_url", WxPayConfig.notify_url);//支付成功后的回调地址
			packageParams.put("trade_type", WxPayConfig.TRADETYPE);//支付方式
			packageParams.put("openid", openid);
			   
	        	String prestr = PayUtil.createLinkString(packageParams); // 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串 
	        
	        	//MD5运算生成签名，这里是第一次签名，用于调用统一下单接口
	        	String mysign = PayUtil.sign(prestr, WxPayConfig.key, "utf-8").toUpperCase();
	        
	        //拼接统一下单接口使用的xml数据，要将上一步生成的签名一起拼接进去
	        String xml = "" + "" + WxPayConfig.appid + "" 
                    + "" 
                    + "" + WxPayConfig.mch_id + "" 
                    + "" + nonce_str + "" 
                    + "" + WxPayConfig.notify_url + "" 
                    + "" + openid + "" 
                    + "" + "123456789" + "" 
                    + "" + spbill_create_ip + "" 
                    + "" + "1" + ""
                    + "" + WxPayConfig.TRADETYPE + "" 
                    + "" + mysign + ""
                    + "";
	        
	        System.out.println("调试模式_统一下单接口 请求XML数据：" + xml);

	        //调用统一下单接口，并接受返回的结果
	        String result = PayUtil.httpRequest(WxPayConfig.pay_url, "POST", xml);
	        
	        System.out.println("调试模式_统一下单接口 返回XML数据：" + result);
	        
	        // 将解析结果存储在HashMap中   
	        Map map = PayUtil.doXMLParse(result);
	        
	        String return_code = (String) map.get("return_code");//返回状态码
	        
		    Map response = new HashMap();//返回给小程序端需要的参数
	        if(return_code.equals("SUCCESS")){   
	            String prepay_id = (String) map.get("prepay_id");//返回的预付单信息   
	            response.put("nonceStr", nonce_str);
	            response.put("package", "prepay_id=" + prepay_id);
	            Long timeStamp = System.currentTimeMillis() / 1000;   
	            response.put("timeStamp", timeStamp + "");//这边要将返回的时间戳转化成字符串，不然小程序端调用wx.requestPayment方法会报签名错误
	            //拼接签名需要的参数
	            String stringSignTemp = "appId=" + WxPayConfig.appid + "&nonceStr=" + nonce_str + "&package=prepay_id=" + prepay_id+ "&signType=MD5&timeStamp=" + timeStamp;   
	            //再次签名，这个签名用于小程序端调用wx.requesetPayment方法
	            String paySign = PayUtil.sign(stringSignTemp, WxPayConfig.key, "utf-8").toUpperCase();
	            
	            response.put("paySign", paySign);
	        }
			
	        response.put("appid", WxPayConfig.appid);
			
	        return response;
		}catch(Exception e){
			e.printStackTrace();
		}
		return null;
	}
	/**
	 * StringUtils工具类方法
	 * 获取一定长度的随机字符串，范围0-9，a-z
	 * @param length：指定字符串长度
	 * @return 一定长度的随机字符串
	 */
	public static String getRandomStringByLength(int length) {
        String base = "abcdefghijklmnopqrstuvwxyz0123456789";
        Random random = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(base.length());
            sb.append(base.charAt(number));
        }
        return sb.toString();
       }
	/**
	 * IpUtils工具类方法
	 * 获取真实的ip地址
	 * @param request
	 * @return
	 */
	public static String getIpAddr(HttpServletRequest request) {
		String ip = request.getHeader("X-Forwarded-For");
	    if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
	         //多次反向代理后会有多个ip值，第一个ip才是真实ip
	    	int index = ip.indexOf(",");
	        if(index != -1){
	            return ip.substring(0,index);
	        }else{
	            return ip;
	        }
	    }
	    ip = request.getHeader("X-Real-IP");
	    if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
	       return ip;
	    }
	    return request.getRemoteAddr();
	}

​

​

WxPayConfig小程序配置文件

/**
 * 小程序微信支付的配置文件
 * @author 
 *
 */
public class WxPayConfig {
	//小程序appid
	public static final String appid = "";
	//微信支付的商户id
	public static final String mch_id = "";
	//微信支付的商户密钥
	public static final String key = "";
	//支付成功后的服务器回调url
	public static final String notify_url = "https://??/??/weixin/api/wxNotify";
	//签名方式，固定值
	public static final String SIGNTYPE = "MD5";
	//交易类型，小程序支付的固定值为JSAPI
	public static final String TRADETYPE = "JSAPI";
	//微信统一下单接口地址
	public static final String pay_url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
}

PayUtils工具类

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.SignatureException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.commons.codec.digest.DigestUtils;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;

public class PayUtil {
	 /**  
     * 签名字符串  
     * @param text需要签名的字符串  
     * @param key 密钥  
     * @param input_charset编码格式  
     * @return 签名结果  
     */   
    public static String sign(String text, String key, String input_charset) {   
        text = text + "&key=" + key;   
        return DigestUtils.md5Hex(getContentBytes(text, input_charset));   
    }   
    /**  
     * 签名字符串  
     *  @param text需要签名的字符串  
     * @param sign 签名结果  
     * @param key密钥  
     * @param input_charset 编码格式  
     * @return 签名结果  
     */   
    public static boolean verify(String text, String sign, String key, String input_charset) {   
        text = text + key;   
        String mysign = DigestUtils.md5Hex(getContentBytes(text, input_charset));   
        if (mysign.equals(sign)) {   
            return true;   
        } else {   
            return false;   
        }   
    }   
    /**  
     * @param content  
     * @param charset  
     * @return  
     * @throws SignatureException  
     * @throws UnsupportedEncodingException  
     */   
    public static byte[] getContentBytes(String content, String charset) {   
        if (charset == null || "".equals(charset)) {   
            return content.getBytes();   
        }   
        try {   
            return content.getBytes(charset);   
        } catch (UnsupportedEncodingException e) {   
            throw new RuntimeException("MD5签名过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);   
        }   
    }   
    
    private static boolean isValidChar(char ch) {   
        if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z'))   
            return true;   
        if ((ch >= 0x4e00 && ch <= 0x7fff) || (ch >= 0x8000 && ch <= 0x952f))   
            return true;// 简体中文汉字编码   
        return false;   
    }   
    /**  
     * 除去数组中的空值和签名参数  
     * @param sArray 签名参数组  
     * @return 去掉空值与签名参数后的新签名参数组  
     */   
    public static Map paraFilter(Map sArray) {   
        Map result = new HashMap();   
        if (sArray == null || sArray.size() <= 0) {   
            return result;   
        }   
        for (String key : sArray.keySet()) {   
            String value = sArray.get(key);   
            if (value == null || value.equals("") || key.equalsIgnoreCase("sign")   
                    || key.equalsIgnoreCase("sign_type")) {   
                continue;   
            }   
            result.put(key, value);   
        }   
        return result;   
    }   
    /**  
     * 把数组所有元素排序，并按照“参数=参数值”的模式用“&”字符拼接成字符串  
     * @param params 需要排序并参与字符拼接的参数组  
     * @return 拼接后字符串  
     */   
    public static String createLinkString(Map params) {   
        List keys = new ArrayList(params.keySet());   
        Collections.sort(keys);   
        String prestr = "";   
        for (int i = 0; i < keys.size(); i++) {   
            String key = keys.get(i);   
            String value = params.get(key);   
            if (i == keys.size() - 1) {// 拼接时，不包括最后一个&字符   
                prestr = prestr + key + "=" + value;   
            } else {   
                prestr = prestr + key + "=" + value + "&";   
            }   
        }   
        return prestr;   
    }   
    /**  
     *  
     * @param requestUrl请求地址  
     * @param requestMethod请求方法  
     * @param outputStr参数  
     */   
    public static String httpRequest(String requestUrl,String requestMethod,String outputStr){   
        // 创建SSLContext   
        StringBuffer buffer = null;   
        try{   
	        URL url = new URL(requestUrl);   
	        HttpURLConnection conn = (HttpURLConnection) url.openConnection();   
	        conn.setRequestMethod(requestMethod);   
	        conn.setDoOutput(true);   
	        conn.setDoInput(true);   
	        conn.connect();   
	        //往服务器端写内容   
	        if(null !=outputStr){   
	            OutputStream os=conn.getOutputStream();   
	            os.write(outputStr.getBytes("utf-8"));   
	            os.close();   
	        }   
	        // 读取服务器端返回的内容   
	        InputStream is = conn.getInputStream();   
	        InputStreamReader isr = new InputStreamReader(is, "utf-8");   
	        BufferedReader br = new BufferedReader(isr);   
	        buffer = new StringBuffer();   
	        String line = null;   
	        while ((line = br.readLine()) != null) {   
	        	buffer.append(line);   
	        }   

                br.close();
        }catch(Exception e){   
            e.printStackTrace();   
        }
        return buffer.toString();
    }     
    public static String urlEncodeUTF8(String source){   
        String result=source;   
        try {   
            result=java.net.URLEncoder.encode(source, "UTF-8");   
        } catch (UnsupportedEncodingException e) {   
            // TODO Auto-generated catch block   
            e.printStackTrace();   
        }   
        return result;   
    } 
	/**
	 * 解析xml,返回第一级元素键值对。如果第一级元素有子节点，则此节点的值是子节点的xml数据。
	 * @param strxml
	 * @return
	 * @throws JDOMException
	 * @throws IOException
	 */
	public static Map doXMLParse(String strxml) throws Exception {
		if(null == strxml || "".equals(strxml)) {
			return null;
		}
		/*=============  !!!!注意，修复了微信官方反馈的漏洞，更新于2018-10-16  ===========*/
		try {
            Map data = new HashMap();
            // TODO 在这里更换
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            documentBuilderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
            documentBuilderFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);
            documentBuilderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
            documentBuilderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
            documentBuilderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
            documentBuilderFactory.setXIncludeAware(false);
            documentBuilderFactory.setExpandEntityReferences(false);

            InputStream stream = new ByteArrayInputStream(strxml.getBytes("UTF-8"));
            org.w3c.dom.Document doc = documentBuilderFactory.newDocumentBuilder().parse(stream);
            doc.getDocumentElement().normalize();
            NodeList nodeList = doc.getDocumentElement().getChildNodes();
            for (int idx = 0; idx < nodeList.getLength(); ++idx) {
                Node node = nodeList.item(idx);
                if (node.getNodeType() == Node.ELEMENT_NODE) {
                    org.w3c.dom.Element element = (org.w3c.dom.Element) node;
                    data.put(element.getNodeName(), element.getTextContent());
                }
            }
            try {
                stream.close();
            } catch (Exception ex) {
                // do nothing
            }
            return data;
        } catch (Exception ex) {
            throw ex;
        }
	}
	/**
	 * 获取子结点的xml
	 * @param children
	 * @return String
	 */
	public static String getChildrenText(List children) {
		StringBuffer sb = new StringBuffer();
		if(!children.isEmpty()) {
			Iterator it = children.iterator();
			while(it.hasNext()) {
				Element e = (Element) it.next();
				String name = e.getName();
				String value = e.getTextNormalize();
				List list = e.getChildren();
				sb.append("<" + name + ">");
				if(!list.isEmpty()) {
					sb.append(getChildrenText(list));
				}
				sb.append(value);
				sb.append("");
			}
		}
		
		return sb.toString();
	}
	public static InputStream String2Inputstream(String str) {
		return new ByteArrayInputStream(str.getBytes());
	}
}

三、小程序端发起最终支付，调用微信付款

doWxPay(param){
		//小程序发起微信支付
            wx.requestPayment({
              timeStamp: param.data.timeStamp,//记住，这边的timeStamp一定要是字符串类型的，不然会报错，我这边在java后端包装成了字符串类型了
              nonceStr: param.data.nonceStr,
              package: param.data.package,
              signType: 'MD5',
              paySign: param.data.paySign,
              success: function (event) {
                // success   
                console.log(event);
                
                wx.showToast({
                  title: '支付成功',
                  icon: 'success',
                  duration: 2000
                });
              },
              fail: function (error) {
                // fail   
                console.log("支付失败")
                console.log(error)
              },
              complete: function () {
                // complete   
                console.log("pay complete")
              }
            });
	}

 

四、微信服务器通知java后端

 

/**
     * @Description:微信支付
     * @return
     * @throws Exception
     */
    @RequestMapping(value="/wxNotify")
    @ResponseBody
    public void wxNotify(HttpServletRequest request,HttpServletResponse response) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine()) != null){
            sb.append(line);
        }
        br.close();
        //sb为微信返回的xml
        String notityXml = sb.toString();
        String resXml = "";
        System.out.println("接收到的报文：" + notityXml);

        Map map = PayUtil.doXMLParse(notityXml);

        String returnCode = (String) map.get("return_code");
        if("SUCCESS".equals(returnCode)){
            //验证签名是否正确
            Map validParams = PayUtil.paraFilter(map);  //回调验签时需要去除sign和空值参数
            String validStr = PayUtil.createLinkString(validParams);//把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
            String sign = PayUtil.sign(validStr, WxPayConfig.key, "utf-8").toUpperCase();//拼装生成服务器端验证的签名
            //根据微信官网的介绍，此处不仅对回调的参数进行验签，还需要对返回的金额与系统订单的金额进行比对等
            if(sign.equals(map.get("sign"))){
                /**此处添加自己的业务逻辑代码start**/


                /**此处添加自己的业务逻辑代码end**/
                //通知微信服务器已经支付成功
                resXml = "" + ""
                        + "" + " ";
            }
        }else{
            resXml = "" + ""
                    + "" + " ";
        }
        System.out.println(resXml);
        System.out.println("微信支付回调数据结束");


        BufferedOutputStream out = new BufferedOutputStream(
                response.getOutputStream());
        out.write(resXml.getBytes());
        out.flush();
        out.close();
    }