微信支付官方文档：https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=7_7&index=6
前端代码demo (JSP页面)：
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1,user-scalable=0">
<title>订单支付</title>
<link rel="stylesheet" href="//cdn.bootcss.com/weui/1.1.1/style/weui.min.css">
<script type="text/javascript" src="//cdn.bootcss.com/jquery/3.1.1/jquery.js"></script>
<script type="text/javascript" src="https://api.map.baidu.com/api?v=2.0&ak=PDzweVAQXotI9pGAyDjzeQWN3U66LS2S&s=1"></script>
<link href="https://cdn.bootcss.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet">
<link rel="stylesheet" href="../css/myedit.css" />
</head>
<body ontouchstart >
<input id="openId" type="hidden" value="${eaporLoginOpenId }"/>
<span>openId:</span><span id="o"></span>
<a class="weui-btn weui-btn_plain-default" style="margin-top:100px;">0.01元</a>
<a id="pay" class="weui-btn weui-btn_primary">立即支付</a>
<p id="sr"></p>
<script>
function onBridgeReady(a){
var result = JSON.parse(a);
WeixinJSBridge.invoke(
'getBrandWCPayRequest', {
"appId":String(result.appId),//公众号名称，由商户传入
"timeStamp":String(result.timeStamp),//时间戳，自1970年以来的秒数
"nonceStr":String(result.nonceStr),//随机串
"package":String(result.packages),
"signType":String(result.signType),//"MD5"//微信签名方式：
"paySign":String(result.paySign)//微信签名
},
function(res){
if (res.err_msg == "get_brand_wcpay_request:ok") {
//alert("微信支付成功!");
window.location="wx_payResult.jsp";
} /* else if (res.err_msg == "get_brand_wcpay_request:cancel") {
alert("用户取消支付!");
} else {
alert(res.err_msg);
alert("支付失败!");
} */
// 使用以上方式判断前端返回,微信团队郑重提示：res.err_msg将在用户支付成功后返回 ok，但并不保证它绝对可靠。
}
);
}
$(function(){
$('#o').html($('#openId').val());
});
$('#pay').on('click',function(){
$.ajax({
type:'post',
url:'../../netTestPay/first',
data:{body:'酒店房间预订单',total_fee:1,out_trade_no:String(new Date().getTime()),openId:$('#openId').val()},
dataType:'json',
success:function(result){
if (typeof WeixinJSBridge == "undefined"){
if( document.addEventListener ){
document.addEventListener('WeixinJSBridgeReady', onBridgeReady, false);
}else if (document.attachEvent){
document.attachEvent('WeixinJSBridgeReady', onBridgeReady);
document.attachEvent('onWeixinJSBridgeReady', onBridgeReady);
}
}else{
onBridgeReady(JSON.stringify(result));
$('#sr').html(JSON.stringify(result));
}
}
});
});
</script>
</body>
</html>