微信app支付(android端+java后台)

<activity
    android:name=".wxapi.WXPayEntryActivity"
    android:screenOrientation="portrait"
    android:exported="true"
    android:launchMode="singleTop"/>

</application>
WXPayEntryActivity 代码详情(支付完成后，onResp会被调用，BaseResp.ErrCode.ERR_OK 表明支付成功)
public class WXPayEntryActivity extends Activity implements IWXAPIEventHandler {

private static final String TAG = "WXPayEntryActivity";

private IWXAPI api;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Constant.wxApi.handleIntent(getIntent(), this);
}

@Override
protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    setIntent(intent);
    api.handleIntent(intent, this);
}

@Override
public void onReq(BaseReq req) {
}

/**
 * 得到支付结果回调
 */
@Override
public void onResp(BaseResp resp)
{
    Log.i(TAG, "onPayFinish, errCode = " + resp.errCode);

    String strPayResult = "";
    switch (resp.errCode) {
        case BaseResp.ErrCode.ERR_OK:
            Toast.makeText(this, "付款成功！", Toast.LENGTH_SHORT).show();
            break;
        case BaseResp.ErrCode.ERR_USER_CANCEL:
            //分享取消
            //Toast.makeText(this, "付款取消！", Toast.LENGTH_SHORT).show();
            //Constant.WEIXIN_PAY_STATUS = "PAY_CANCEL";
            break;
        case BaseResp.ErrCode.ERR_AUTH_DENIED:
            //分享拒绝
            //Toast.makeText(this, "付款拒绝！", Toast.LENGTH_SHORT).show();
            //Constant.WEIXIN_PAY_STATUS = "PAY_DENY";
            break;
    }

    //向之前页面返回支付结果信息
    /*Intent intent = new Intent();
    intent.putExtra("payResult", strPayResult);
    setResult(100, intent);*/
    finish();
}

}
3.3 支付按钮的点击事件

通过http协议向后台请求相应的预支付信息, 根据这些信息组装相应的信息来调用微信接口, 拉起微信支付界面
    @OnClick(R.id.pay)

4.1 后台代码结构图

4.2 微信配置信息 Config.properties

4.3 方法wxpay用于生成预支付订单信息

方法notifyWeiXinPay用于微信支付成功后的回调, 注意: 在手机端使用微信支付成功后，微信服务器会根据提供的回调地址进行回调, parameterMap.put("notify_url", wxnotify); (见下面代码) 

String timeMillis = String.valueOf(System.currentTimeMillis() / 1000);
String randomString = PayCommonUtil.getRandomString(32);
//支付成功后的回调函数
public static String wxnotify = "http://gepanjiang.hk1.tunnelfrp.cc/WxPay/pay/notifyWeiXinPay.htm";

public PayController() {
    System.out.println("MainController构造函数");
}

/**
 * @param totalAmount    支付金额
 * @param description    描述
 * @param request
 * @return
 */
@RequestMapping(value = "/wxpay.htm", produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public Result wxpay(HttpServletRequest request) {
    Result result = new Result();
    Long userId = new Long(1);//baseController.getUserId();

    BigDecimal totalAmount = new BigDecimal(request.getParameter("totalPrice"));
    String trade_no = "";
    String description="";
    try {
        trade_no = new String(request.getParameter("orderNum").getBytes("ISO-8859-1"),"UTF-8");
        description = request.getParameter("description");
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    String openId = "";

    Map<String, String> map = weixinPrePay(trade_no,totalAmount,description,openId,request);
    SortedMap<String, Object> finalpackage = new TreeMap<String, Object>();
    finalpackage.put("appId", ConfigManager.getInstance().getConfigItem("WXAppID")/*PayCommonUtil.APPID*/);
    finalpackage.put("mchId", ConfigManager.getInstance().getConfigItem("MCH_ID"));
    Long time = (System.currentTimeMillis() / 1000);
    finalpackage.put("timeStamp", time.toString());
    finalpackage.put("nonceStr", map.get("nonce_str"));
    finalpackage.put("prepayId", map.get("prepay_id"));
    finalpackage.put("package", "Sign=WXPay");
    finalpackage.put("signType", "MD5");
    String sign = PayCommonUtil.createSign("UTF-8", finalpackage);
    finalpackage.put("paySign", sign);//官方文档上是sign，当前示例代码是paySign 可能以前的

    WeiXinPrePay prePay = new WeiXinPrePay();
    prePay.setAppId(ConfigManager.getInstance().getConfigItem("WXAppID"));
    prePay.setMchId(ConfigManager.getInstance().getConfigItem("MCH_ID"));
    prePay.setTimeStamp(time.toString());
    prePay.setNonceStr(map.get("nonce_str"));
    prePay.setPrepayId(map.get("prepay_id"));
    prePay.setSignType("MD5");
    prePay.setPaySign("paySign");
    result.setData(prePay);
    result.setStateCode(GeneralConstant.SUCCESS);
    result.setDesc("微信支付加载成功");

    return result;
} 

/**
 * 统一下单
 * 应用场景：商户系统先调用该接口在微信支付服务后台生成预支付交易单，返回正确的预支付交易回话标识后再在APP里面调起支付。
 * @param trade_no
 * @param totalAmount
 * @param description
 * @param openid
 * @param sym
 * @param request
 * @return
 */
@SuppressWarnings("unchecked")
public Map<String, String> weixinPrePay(String trade_no,BigDecimal totalAmount,
        String description, String openid, HttpServletRequest request) {
    SortedMap<String, Object> parameterMap = new TreeMap<String, Object>();
    parameterMap.put("appid", ConfigManager.getInstance().getConfigItem("WXAppID"));  //应用appid
    parameterMap.put("mch_id", ConfigManager.getInstance().getConfigItem("MCH_ID")/*PayCommonUtil.MCH_ID*/);  //商户号
    //parameterMap.put("device_info", "WEB");
    parameterMap.put("nonce_str", randomString);
    parameterMap.put("body", description);
    parameterMap.put("out_trade_no", trade_no);
    parameterMap.put("fee_type", "CNY");
    System.out.println("jiner");
    BigDecimal total = totalAmount.multiply(new BigDecimal(100));  //接口中参数支付金额单位为【分】，参数值不能带小数，所以乘以100
    java.text.DecimalFormat df=new java.text.DecimalFormat("0");
    parameterMap.put("total_fee", df.format(total));
    System.out.println("jiner2");
    parameterMap.put("spbill_create_ip", PayCommonUtil.getRemoteHost(request));
    parameterMap.put("notify_url", wxnotify);
    parameterMap.put("trade_type", "APP");//"JSAPI"
    //trade_type为JSAPI是 openid为必填项
    //parameterMap.put("openid", openid);
    System.out.println("");
    String sign = PayCommonUtil.createSign("UTF-8", parameterMap);
    System.out.println("jiner2");
    parameterMap.put("sign", sign);
    String requestXML = PayCommonUtil.getRequestXml(parameterMap);
    System.out.println(requestXML);
    String result = PayCommonUtil.httpsRequest(
            "https://api.mch.weixin.qq.com/pay/unifiedorder", "POST",
            requestXML);
    System.out.println(result);
    Map<String, String> map = null;
    try {
        map = PayCommonUtil.doXMLParse(result);
    } catch (JDOMException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return map;
}

/**
 * 此函数会被执行多次，如果支付状态已经修改为已支付，则下次再调的时候判断是否已经支付，如果已经支付了，则什么也执行
 * @param request
 * @param response
 * @return
 * @throws IOException
 * @throws JDOMException
 */
@RequestMapping(value = "notifyWeiXinPay.htm", produces = MediaType.APPLICATION_JSON_VALUE)

    Map<String,String> return_data = new HashMap<String,String>();
    if (!PayCommonUtil.isTenpaySign(params)) {
        // 支付失败
        return_data.put("return_code", "FAIL");
        return_data.put("return_msg", "return_code不正确");
        return StringUtil.GetMapToXML(return_data);
    } else {
        System.out.println("===============付款成功==============");
        // ------------------------------
        // 处理业务开始
        // ------------------------------
        // 此处处理订单状态，结合自己的订单数据完成订单状态的更新
        // ------------------------------

        String total_fee = params.get("total_fee");
        double v = Double.valueOf(total_fee) / 100;
        String out_trade_no = String.valueOf(Long.parseLong(params.get("out_trade_no").split("O")[0]));
        Date accountTime = DateUtil.stringtoDate(params.get("time_end"), "yyyyMMddHHmmss");
        String ordertime = DateUtil.dateToString(new Date(), "yyyy-MM-dd HH:mm:ss");
        String totalAmount = String.valueOf(v);
        String appId = params.get("appid");
        String tradeNo = params.get("transaction_id");

        return_data.put("return_code", "SUCCESS");
        return_data.put("return_msg", "OK");
        return StringUtil.GetMapToXML(return_data);
    }
}

}

原文地址：http://blog.51cto.com/13636962/2085772