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1.公众号开发，首先需要微信公众号的appId,secret 相当于账号密码

2.到公众号后台配置域名，微信用户授权，微信支付目录（在公众号平台配置不了，要到商户后台配置）

3.配置好了之后就可以开发了，直接上代码

微信用户授权

/**
* Desc:请求微信接口URL1获取code跳转到redirect_url,请求微信接口URL2获取openId
* param:
* return:openid
* Author:LiuChuanting
* Date:2017/9/14
**/
public void getUrlCode(){
String status = this.getRequest().getParameter("status");
if(StringUtils.isNotBlank(status)){
CacheKit.put("reder", "status_code","1");
}
String url = Constant.WECHAT_INFO.URL1;
   String appid= Constant.WECHAT_INFO.APP_ID;
   String REDIRECT_URI = Constant.WECHAT_INFO.REDIRECT_URL;
   url  = url.replace("APPID",ToolUtil.str2Encode(appid)); 
   url  = url.replace("REDIRECT_URI",ToolUtil.str2Encode(REDIRECT_URI));
   //getUserInfo();
   this.redirect(url);
}

/**
* Desc:请求微信接口URL2获取openId
* param:code
* return:无
* Author:LiuChuanting
* Date:2017/9/14
**/
public void getUrlOpenid(){
String code = this.getPara("code");
String openId = HttpClientConnectionManager.getOpendId(code);
this.setAttr("openId",openId);
String status = CacheKit.get("reder","status_code");
if("1".equals(status)){
//从菜单进入个人中心
CacheKit.remove("reder","status_code");
this.render("/admin/page/redirectCenter.jsp");
}else{
//去下单用户授权
this.render("/admin/page/redirect.jsp");
}

}

用户授权原理是后台获取openid 返回到第三方页面 在第三方页面进行跳转到H5页面，并且带上openId ,一般我们放到cookie

 

<script type="text/javascript"> 
function setCookie(key, value) {   
if(!key) return;
var option = {
Domain: "",
Path: "/"
};
if(/(\.cn|\.com)/.test(window.location.host)) {
var tmp = window.location.host.split("\.");
var t = tmp[tmp.length - 1].split(":");
option.Domain = "." + tmp[tmp.length - 2] + "." + t[0];
}
if(typeof(value) === "object") {
value = JSON.stringify(value);
} 
var tmp = "";
for(var s in option ){
tmp += ";" + s + "=" + option[s]; 
}

document.cookie = key + "=" + escape(value) + tmp;
   /*  var Days = 30;  
    var exp = new Date();  
    exp.setTime(exp.getTime() + 60 * 5000);//过期时间5分钟  
   */
    //document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();  
}
setCookie("openId",'${openId}');
window.location.href = "http://wechat.qzt360.com/page/index.html";
 

</script>

获取微信用户的基本信息，根据页面传过来的openId查询ACCESS_TOKEN

在根据获取的ACCESS_TOKEN请求微信服务器获取用户信息并然后返回JSONObject对象

/**
* Desc:获取微信用户信息
* param:openid
* return:无
* Author:LiuChuanting
* Date:2017/9/14
**/
public void getUserInfo(){
String openId = getOpenId();
   String user = HttpClientConnectionManager.getUserInFo(openId);
   renderRb(user);
}

/**
* Desc:获取cookie openId
* param:
* return:无
* Author:LiuChuanting
* Date:2017/9/21
**/
public String getOpenId(){
String openId = "";
   javax.servlet.http.Cookie[] cookies = this.getRequest().getCookies();
   for(javax.servlet.http.Cookie cookie : cookies){
       if(cookie.getName().equals("openId")){
        openId = cookie.getValue();
       }
    }
return openId;
}

/**
* Desc:获取cookie 订单编号
* param:
* return:订单编号
* Author:LiuChuanting
* Date:2017/9/21
**/
public String getOrderCode(){
String orderCode = "";
   javax.servlet.http.Cookie[] cookies = this.getRequest().getCookies();
   for(javax.servlet.http.Cookie cookie : cookies){
       if(cookie.getName().equals("orderCode")){
        orderCode = cookie.getValue();
       }
    }
return orderCode;
}

获取access_token的原理是 先去缓存拿 如果缓存为空，去请求微信服务器，并更新到缓存中，如果从缓存拿到不为空 根据access_token请求用户信息，报access_token过期（默认两个小时过期）再去请求拿access_token并更新到缓存（获取access_token需要公众号的appid和secret的两个参数就可以请求到）

//根据用户ID和token获取用户信息
public static String getUserInFo(String openId){
DefaultHttpClient client = new DefaultHttpClient();
JSONObject jsonObject = null;
Object token = CacheKit.get("ACCESS_TOKEN","token");
//第一次请求token为空，需要去获取
if(token == null){
String accessToken = HttpClientConnectionManager.getAccessToken();
token = accessToken;
//token放到缓存
CacheKit.put("ACCESS_TOKEN","token", accessToken);
}
String url = Constant.WECHAT_INFO.GET_USERINFO_URL;
url = url.replace("ACCESS_TOKEN",token.toString()).replace("OPENID",openId);
HttpGet get = HttpClientConnectionManager.getGetMethod(url);
HttpResponse response;
try {
response = client.execute(get);
String jsonStr = EntityUtils.toString(response.getEntity(), "utf-8");
jsonObject= (JSONObject) JSON.parse(jsonStr);
if(jsonObject.get("errcode") != null){
//token过期重新获取
String accessToken = HttpClientConnectionManager.getAccessToken();
//token放到缓存
CacheKit.put("ACCESS_TOKEN","token", accessToken);
getUserInFo(openId);
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return jsonObject.toString();
}

微信开发需要的一些参数

/**
* 微信接口参数snsapi_userinfo/snsapi_base
*/
public static class WECHAT_INFO {
public static final String APP_ID = ""; //公众号ID
public static final String SECRET= ""; //公众号秘钥
public static final String ACCESS_TOKEN= "NaR8fNK4LXfaqUekYQhViOpEszPo8mIszyWYA58hKtF5hdxW_0ropKxmR4VeThq8jspiA8Y76-fn8bZZOTnDcG5mCle0ifd19IZPqVED0UCz81dm3P7cpYK3TbZh-HtiHUAcAFAWJP"; //公众号token
public static final String URL1= "https://open.weixin.qq.com/connect/oauth2/authorize?"
+ "appid=APPID&redirect_uri=REDIRECT_URI&response_type=code&scope=snsapi_base&state=STATE#wechat_redirect";//获取code的url
public static final String REDIRECT_URL= "http://wechat.qzt360.com/api/weTrack/getUrlOpenid";//重定向的本地URL返回code
public static final String URL2= "https://api.weixin.qq.com/sns/oauth2/access_token?appid=AppId&secret=AppSecret&code=CODE&grant_type=authorization_code";//获取用户openid的URL
public static final String GET_TOKEN_URL= "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";//获取用户公众号token
public static final String GET_USERINFO_URL= "https://api.weixin.qq.com/cgi-bin/user/info?access_token=ACCESS_TOKEN&openid=OPENID";//获取用户信息
}
/**
* 微信支付参数
*/
public static class WECHAT_PAY {
public static final String CALLBACK_URL = "http://wechat.qzt360.com/api/weTrack/getPayResult"; //请求支付后回调路径
public static final String DESCRIPTION = "企智通设备购买"; //商品描述
public static final String ATTACH = "qztgm"; //附加数据
public static final String MCH_ID = "1488893999"; //商户号
public static final String USER_IP = "192.168.1.1"; //用户终端IP
public static final String PAY_KEY= "BA6B005BEF79E7B95F3E097887HGHGH"; //支付KEY
public static final String SIGN_TYPE= "MD5"; //签名类型
public static final Integer LOGISTICE_MONEY= 15; //运费
public static final String ORDER_URL= "https://api.mch.weixin.qq.com/pay/unifiedorder"; //统一下单URL
}

接下来就是微信支付接口了，支付接口非常简单，首先要先预下单去请求微信服务器，返回prepay_id,通过这个ID进行封装，和生成签名返回给H5页面调用微信支付页面弹窗支付密码的窗口，支付成功后 进行回调修改后台业务状态就OK了。

/**
* Desc:微信支付获取支付配置参数
* param:code
* return:无
* Author:LiuChuanting
* Date:2017/9/19
**/
public void getPayConfig(){
String ipurl = this.getRequest().getRemoteAddr();
String openId = getOpenId();
String orderCode = getOrderCode();
JSONObject json = new JSONObject();


   try {
   //调用微信接口统一下单，获取prepayId
String prepayId = WeChatService.me.getPrepayId(openId,ipurl,orderCode);
//生成支付参数返回到页面请求
json = WeChatService.me.createPayConfig(prepayId);
} catch (Exception e) {
logger.error(e.getMessage());
}
renderRb(json);
}

  /**
     * 统一下单
* @param ipurl 
* @param orderCode2 
     * @Title: unifiedOrder 
     * @Description: TODO 
     * @param: @param openId 微信用户openId
     * @param: @param callbackUrl 回调路径
     * @param: @return
     * @return: PrepayId
     */
public String getPrepayId(String openId, String ipurl, String orderCode) {
Record order = Order.me.selectOrderDetail(orderCode);
Integer price = order.getInt("pay_money");
UnifiedOrder unifiedOrder = new UnifiedOrder();
       unifiedOrder.setAppid(Constant.WECHAT_INFO.APP_ID);
       unifiedOrder.setAttach(Constant.WECHAT_PAY.ATTACH);


       unifiedOrder.setBody(Constant.WECHAT_PAY.DESCRIPTION);
       unifiedOrder.setMch_id(Constant.WECHAT_PAY.MCH_ID);


       String nonce = UUID.randomUUID().toString().substring(0, 30);
       unifiedOrder.setNonce_str(nonce);
       unifiedOrder.setNotify_url(Constant.WECHAT_PAY.CALLBACK_URL);


       unifiedOrder.setOpenid(openId);
       unifiedOrder.setOut_trade_no(orderCode);


       unifiedOrder.setSpbill_create_ip(ipurl);
       unifiedOrder.setTotal_fee(1);
       
       String sign = createUnifiedOrderSign(unifiedOrder);
       unifiedOrder.setSign(sign);
       unifiedOrder.setSign_type(Constant.WECHAT_PAY.SIGN_TYPE);


       /**
        * 转成XML格式
        */
       String xml = XmlKit.getBeanXml(unifiedOrder);


       String response = null;
try {
response = HttpConnection.post(Constant.WECHAT_PAY.ORDER_URL, xml);
} catch (Exception e) {
e.printStackTrace();
}
       Map<String, String> responseMap = XmlKit.getXml2Map(response);


       return responseMap.get("prepay_id");
}

注意签名的参数要跟请求统一下单的参数要保持一致除了key，sign以外，因为你自己生成的签名，和你统一下单的参数一起请求微信服务器接口，微信根据你的参数也生存一个签名，然后跟你的签名进行对比，如果不一致会返回 “签名错误” 状态信息

  /**
     * 获取统一下单签名
     * @Title: createUnifiedOrderSign
     * @Description: TODO
     * @param @param unifiedOrder
     * @param @return    
     * @return String    
     * @throws
     */
    public String createUnifiedOrderSign(UnifiedOrder unifiedOrder){
        StringBuffer sign = new StringBuffer();
        sign.append("appid=").append(unifiedOrder.getAppid());
        /*sign.append("&attach=").append(unifiedOrder.getAttach());*/
        sign.append("&body=").append(unifiedOrder.getBody());
        sign.append("&mch_id=").append(unifiedOrder.getMch_id());
        sign.append("&nonce_str=").append(unifiedOrder.getNonce_str());
        sign.append("&notify_url=").append(unifiedOrder.getNotify_url());
        sign.append("&openid=").append(unifiedOrder.getOpenid());
        sign.append("&out_trade_no=").append(unifiedOrder.getOut_trade_no());
        sign.append("&spbill_create_ip=").append(unifiedOrder.getSpbill_create_ip());
        sign.append("&total_fee=").append(unifiedOrder.getTotal_fee());
        sign.append("&trade_type=").append(unifiedOrder.getTrade_type());
        sign.append("&key=").append(Constant.WECHAT_PAY.PAY_KEY);
        return DigestUtils.md5Hex(sign.toString()).toUpperCase();
    }

微信支付回调

    /**
     * 获取支付配置
     * @Title: createPayConfig
     * @Description: TODO
     * @param @param preayId 统一下单prepay_id
     * @param @return 返回json参数到H5页面调起微信支付
     * @param @throws Exception    
     * @return JsAPIConfig    
     * @throws
     */
    public JSONObject createPayConfig(String prepayId){
    JsAPIConfig config = new JsAPIConfig();
    JSONObject json = new JSONObject();
    try {
            String nonce = UUID.randomUUID().toString();
            String timestamp = Long.toString(System.currentTimeMillis() / 1000);
            String packageName = "prepay_id="+prepayId;
            StringBuffer sign = new StringBuffer();
            sign.append("appId=").append(Constant.WECHAT_INFO.APP_ID);
            sign.append("&nonceStr=").append(nonce);
            sign.append("&package=").append(packageName);
            sign.append("&signType=").append(config.getSignType());
            sign.append("&timeStamp=").append(timestamp);
            sign.append("&key=").append(Constant.WECHAT_PAY.PAY_KEY);
            String signature = DigestUtils.md5Hex(sign.toString()).toUpperCase();


            json.put("appId",Constant.WECHAT_INFO.APP_ID);
            json.put("timeStamp",timestamp);
            json.put("nonceStr",nonce);
            json.put("package",packageName);
            json.put("signType",config.getSignType());
            json.put("paySign",signature);
} catch (Exception e) {
logger.error(e.getMessage());
}
        return json;
    }

    /**
     * 微信支付回调页面
     * @Title: wechatPayNotify
     * @Description: TODO
     * @param @param request
     * @param @param trade_status
     * @param @param out_trade_no
     * @param @param trade_no    
     * @return void    
     * @throws
     */
    public String getPayResult(){
    try {
            Map<String, String> map = XmlKit.getCallbackParams(this.getRequest());
            if (map.get(Constant.RESULT_CODE).toString().equalsIgnoreCase(Constant.STATUS)) {
            //这里写成功后的业务逻辑
            WeChatService.me.finishOrder(map,0);
            logger.equals("支付成功");
            }else{
            logger.equals("支付失败");
            WeChatService.me.finishOrder(map,1);
            }
       } catch (Exception e) {
      logger.error(e.getMessage());
       }
return XmlKit.getPayCallback();
    }