场景介绍

官网介绍地址：https://pay.weixin.qq.com/wiki/doc/api/native.php?chapter=9_1

用户扫描商户展示在各种场景的二维码进行支付。

步骤1：商户根据微信支付的规则，为不同商品生成不同的二维码（如图6.1），展示在各种场景，用于用户扫描购买。

步骤2：用户使用微信“扫一扫”（如图6.2）扫描二维码后，获取商品支付信息，引导用户完成支付（如图6.3）。

图6.1 支付二维码

图6.2 打开微信扫一扫二维码

图6.3 确认支付页面

步骤（3）：用户确认支付，输入支付密码（如图6.4）。

步骤（4）：支付完成后会提示用户支付成功（如图6.5），商户后台得到支付成功的通知，然后进行发货处理。

图6.4 用户确认支付，输入密码

图6.5 支付成功提示

/**
     * 微信扫码支付 模式二
     * @return返回的就是二维中的值
     * @throws Exception
     */
    public String getWxPayQRCode() throws Exception{
        //商户key
        String key = "mlqho2dwhxxxxxxxxxxxv81m1r6i28";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
        Map<String,String> map = new HashMap<String, String>();
        //公众账号ID
        map.put("appid","wssssssxxxxxxxxxe0e5b");
        //商户号
        map.put("mch_id","1xxxxxxxxx2");
        //随机数
        map.put("nonce_str", RandomStringGenerator.getRandomStringByLength(32));
        //商品描述
        map.put("body","香辣鸡腿堡");
        //订单号
        map.put("out_trade_no",sdf.format(new Date()));
        //总金额单位分
        map.put("total_fee","1");
        InetAddress ia = InetAddress.getLocalHost();
        //ip
        map.put("spbill_create_ip",ia.getHostAddress());
        //通知地址
        map.put("notify_url","www.niudao.com");
        //交易类型
        map.put("trade_type","NATIVE");
        //商品ID
        map.put("product_id","10000");
        //签名
        map.put("sign", QRSign.getSign(map, key));
        //请求地址及请求数据
        String url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
        String data = MapToXmlUtil.mapToXml(map);
        //发送请求
        ClientRequest request = new ClientRequest(url);
        request.body("text/xml;charset=utf-8",data);
        ClientResponse response = request.post(String.class);
        //xml字符串转化成json对象
        String result = XMLAndJsonUtil.xmlChangeJson(response.getEntity().toString());
        result = result.replaceAll("\r\n","");
        JSONObject jsonObject = JSONObject.fromObject(result);
        //二维码内容
        String qrCode = "";
        if(jsonObject.get("return_code").toString().equals("SUCCESS")){
            qrCode = jsonObject.get("code_url").toString();
        }
        return qrCode;
    }

import java.util.Random;

/**
 * User: rizenguo
 * Date: 2014/10/29
 * Time: 14:18
 */
public class RandomStringGenerator {

    /**
     * 获取一定长度的随机字符串
     * @param length 指定字符串长度
     * @return 一定长度的字符串
     */
    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();
    }

}

import java.security.MessageDigest;
import java.util.Arrays;
import java.util.Map;

/**
 * Created by Administrator on 16-12-1.
 */
public class QRSign {

    /**
     * 微信支付签名算法sign
     * @param map 请求微支付body
     * @param key 商户key (不是公众号key)
     * @return
     */
    public static String getSign(Map<String,String> map,String key) {
        StringBuffer sb = new StringBuffer();
        String[] keyArr = (String[]) map.keySet().toArray(new String[map.keySet().size()]);//获取map中的key转为array
        Arrays.sort(keyArr);//对array排序
        for (int i = 0, size = keyArr.length; i < size; ++i) {
            if ("sign".equals(keyArr[i])) {
                continue;
            }
            sb.append(keyArr[i] + "=" + map.get(keyArr[i]) + "&");
        }
        sb.append("key=" + key);
        String sign = string2MD5(sb.toString());
        return sign;
    }

    /***
     * MD5加密 生成32位md5码
     */
    public static String string2MD5(String str){
        if (str == null || str.length() == 0) {
            return null;
        }
        char hexDigits[] = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘,
                ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };

        try {
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(str.getBytes("UTF-8"));

            byte[] md = mdTemp.digest();
            int j = md.length;
            char buf[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
                buf[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(buf).toUpperCase();
        } catch (Exception e) {
            return null;
        }
    }
}

import java.util.Map;

/**
 * Created by Administrator on 16-12-1.
 */
public class MapToXmlUtil {
    /**
     * 将map 转化成 xml
     * @param map
     * @return
     */
    public static String mapToXml(Map<String,String> map)throws Exception{
        StringBuilder sb = new StringBuilder();
        sb.append("<xml>");
        for (Map.Entry<String, String> entry : map.entrySet()) {
            sb.append("<" + entry.getKey() + ">" + entry.getValue().toString() + "</" + entry.getKey() + ">");
        }
        sb.append("</xml>");
        return sb.toString();
    }
}

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Created by Administrator on 16-12-1.
 */
public class XMLAndJsonUtil {

    //用于判断是否有子节点,若有就将子节点也进行拼接,若无则返回""
    public static String checkChildEle(Element element) throws DocumentException {
        String json="";
        List<Element> list = new ArrayList<Element>();
        list=element.elements();
        if (list.size()>0) {
            for (Element ele : list) {
                json+= "‘" + ele.getName() + "‘" + ":" + "‘" + ele.getText() + "‘" + "," + "\r\n" + checkChildEle(ele);
            }
        }
        return json;
    }
    //这个方法是将xml字符串转成Json
    public static String xmlChangeJson(String XML) throws DocumentException{
        Document document= DocumentHelper.parseText(XML);
        Element root=document.getRootElement();
        Iterator it=root.elementIterator();
        String json="{";
        while (it.hasNext()) {
            Element element =(Element)it.next();
            String j=checkChildEle(element);
            if (j=="") {
                json+= "‘" + element.getName() + "‘" + ":" + "‘" + element.getText() + "‘" + ","+"\r\n";
            }else {
                json+=j;
            }

        }
        json+="}";
        return json;
    }
    //这个方法是将xml文件转成Json
    public static String xmlChangeJson(File XML) throws DocumentException{
        SAXReader reader=new SAXReader();
        Document document=reader.read(XML);
        Element root=document.getRootElement();
        Iterator it=root.elementIterator();
        String json="{";
        while (it.hasNext()) {
            Element element =(Element)it.next();
            String j=checkChildEle(element);
            if (j=="") {
                json+=element.getName()+":"+element.getText()+","+"\r\n";
            }else {
                json+=j;
            }

        }
        json+="}";
        return json;
    }
}