微信扫描公众号二维码实现登陆

前提条件：
1.微信公众平台为服务号，
2.服务号实现了账号绑定功能，即将open_id 与业务系统中的用户名有对应关系

具体实现原理：
1.用户访问业务系统登陆页时，调用二维码接口，获得二维码的ticketid,同时将sessionid，ticketid和二维码的seceneid保存
2.返回登陆页时，根据ticketid获得微信二维码
3.页面通过ajax发送请求，判断是否已经扫描成功。
4.公众平台服务监测到扫描事件，更新seceneid中扫描二维码的业务系统用户名
4.当ajax监测到扫描成功，并返回有业务系统用户名，即可做模拟登陆！

具体代码：
根据sceneID获取，获取ticketId，
sceneId可以为sessionID,或者自定义的其他任何值，但必须保证不重复
注意：这里请求的type可以为临时二维码或永久二维码，具体区别可以参看微信公众平台的开发者文档。

public static String getSceneTicket(String type,String sceneId){
		WxScene scene = new WxScene();
		scene.setAction_name(type);
		scene.setSceneId(Integer.parseInt(sceneId));
		scene.setExpire_seconds(1800);
		String jsonScene = JSONObject.fromObject(scene).toString();
		String url = WeixinContents.qr_scene_ticket_url.replaceAll("ACCESS_TOKEN", getAccessToken(WeixinContents.appid,WeixinContents.appsecret).getToken());
		System.out.println(jsonScene);
		JSONObject jsonObject = httpRequest(url, "POST", jsonScene);
		int result = 0;
		String ticket = "";
		if (null != jsonObject) {
			if (jsonObject.containsKey("errcode")) {
				result = jsonObject.getInt("errcode");
			}else{
				ticket = jsonObject.getString("ticket");
			}
		}
		return ticket;
	}

2.扫描二维码登陆的几个action

@ActionKey("/")
	@ClearInterceptor(ClearLayer.ALL)
	public void index() {
		LoginUser u = (LoginUser)getSessionAttr("LoginUser");
		setAttr("root", this.getRequest().getContextPath());
		if(null==u){
			setAttr("ticketId",wxTicket());
			render("/WEB-INF/login.html");
		}else{
			redirect("/index");
		}
	}
	private String wxTicket() {
		int sceneId = Db.queryInt("select SEQ_WX_SCENE.Nextval from dual");
		String ticketId = WeixinHttpUtils.getSceneTicket("QR_SCENE", sceneId+"");
		setSessionAttr("ticketId",ticketId);
		setSessionAttr("sessionId",this.getRequest().getSession().getId());
		String sql = "insert into wx_scence_logon(id,sessionid,ticketid,SCENCE_ID) values(sys_guid(),?,?,?)";
		Db.update(sql,this.getRequest().getSession().getId(),ticketId,sceneId);
		return ticketId;
	}
	@ActionKey("/cxTicket")
	@ClearInterceptor(ClearLayer.ALL)
	public void cxTicket(){
		String ticketId = getPara("ticketId");
		String sessionid = getPara("sessionId");
		int i=0;
		while(i<10){
			Record r = Db.findFirst("select id from wx_scence_logon l,wx_user u where u.open_id = l.open_id and l.ticketid = ? and l.sessionId = ?",ticketId,sessionid);
			if(r!=null&&StringUtils.isNotEmpty(r.getStr("id"))){
					setAttr("success","1");
					setAttr("logonId",r.getStr("id"));
					break;
			}else{
				setAttr("success","0");
				try {
					Thread.sleep(5000);
					i++;
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
		render(new JsonRender().forIE());
	}
	@ActionKey("/ticketLogon")
	@ClearInterceptor(ClearLayer.ALL)
	public void ticketLogon(){
		String id = getPara("ticketId");
		Record r = Db.findFirst("select user_id as username from wx_scence_logon l,wx_user u where u.open_id = l.open_id and l.id = ?",id);
		if(r!=null&&StringUtils.isNotEmpty(r.getStr("username"))){
			String username = r.getStr("username");
			LoginUser user = LoginUser.dao.findFirst("select user_id,xm,department_id,departmentname,userpw from gy_user u where u.username = ? and u.userlockstate = '1' ",username);
			String permSql = "select distinct p.* from hr_user_role t,hr_role r,hr_role_perm m,hr_perms p where t.role_id = r.id and m.role_id = r.id and m.perm_id = p.id and user_id = ?";
			List<Record> perms = Db.find(permSql,new Object[]{user.getStr("user_id")});
			if(perms!=null&&perms.size()>0){
				this.getSession().removeAttribute("USER_PERMS");
				setSessionAttr("USER_PERMS",perms);
				getRequest().getSession().setAttribute("LoginUser",user);
			}
		}
		this.redirect("/main");
	}

3.
登陆页面
二维码显示

<img src="https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=${ticketId!}" width="250px"/>

定时查询扫描状态

function wxCxTikcet(){
	$.getJSON("${root!}/cxTicket",{ticketId:"${ticketId}",sessionId:"${sessionId}"},function(data){
		//alert(data.success=="1");
		if(data.success=='1'){
			_logon(data.logonId);
			//window.location.href="${root!}/ticketLogon/"+data.logonId;
		}
	});
}
var t_int = window.setInterval("wxCxTikcet()",5000);

4.公众平台代码

}else if(eventType.equalsIgnoreCase(MessageUtil.EVENT_TYPE_SCAN)){
							String scene_id = eventKey;
							if(Integer.parseInt(eventKey)==0){
								respContent = "扫描参数出错！请刷新重试！";
							}else{
								respContent = getSceneContent(scene_id,fromUserName);
							}
					}

private static String getSceneContent(String sceneId,String fromUserName){
		String sql ="select * from WX_SCENCE_LOGON  where scence_id = ?";
		Record r = Db.findFirst(sql,sceneId);
		if(r!=null){
			String updateSql = "update wx_scence_logon set open_id = ? where id = ?";
			Db.update(updateSql,fromUserName,r.getStr("id"));
			return "您已成功登陆***系统！";
		}
}

说明，框架使用jfinal 1.5