再通过code获取authtoken，从authtoken中取出openid给前台
微信端一定不要忘记设定网页账号中的授权回调页面域名
流程图如下
主要代码
页面js代码
/* 写cookie */ function setCookie(name, value) { var Days = 30; var exp = new Date(); exp.setTime(exp.getTime() + Days * 24 * 60 * 60 * 1000); document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString() + ";path=https://www.jb51.net/"; } /* 读cookie */ function getCookie(name) { var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)")); if (arr != null) { return unescape(arr[2]); } return null; } /* 获取URL参数 */ function getUrlParams(name) { var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)", "i"); var r = window.location.search.substr(1).match(reg); if (r != null) { return unescape(r[2]); } return null; } /* 获取openid */ function getOpenId(url) { var openid = getCookie("usropenid"); if (openid == null) { openid = getUrlParams('openid'); alert("openid="+openid); if (openid == null) { window.location.href = "wxcode?url=" + url; } else { setCookie("usropenid", openid); } } }
WxCodeServlet代码
//访问微信获取code @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String state = req.getParameter("url"); //WxOpenIdServlet的地址 String redirect ="http://"+Configure.SITE+"/wxopenid"; redirect = URLEncoder.encode(redirect, "utf-8"); StringBuffer url = new StringBuffer("https://open.weixin.qq.com/connect/oauth2/authorize?appid=") .append(Configure.APP_ID).append("&redirect_uri=").append(redirect) .append("&response_type=code&scope=snsapi_base&state=").append(state).append("#wechat_redirect"); resp.sendRedirect(url.toString()); }
WxOpenIdServlet代码
//访问微信获取openid @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String code = req.getParameter("code"); String state = req.getParameter("state"); Result ret = new Result(); AuthToken token = WXUtil.getAuthToken(code); if(null != token.getOpenid()){ ret.setCode(0); log.info("====openid=="+token.getOpenid()); Map<String,String> map = new HashMap<String,String>(); map.put("openid", token.getOpenid()); map.put("state", state); ret.setData(map); }else{ ret.setCode(-1); ret.setMsg("登录错误"); } String redUrl = state+"?openid="+token.getOpenid(); resp.sendRedirect(redUrl); }
获取AuthToken（WXUtil.getAuthToken(code)）代码
public static AuthToken getAuthToken(String code){ AuthToken vo = null; try { String uri = "https://api.weixin.qq.com/sns/oauth2/access_token?"; StringBuffer url = new StringBuffer(uri); url.append("appid=").append(Configure.APP_ID); url.append("&secret=").append(Configure.APP_SECRET); url.append("&code=").append(code); url.append("&grant_type=").append("authorization_code"); HttpURLConnection conn = HttpClientUtil.CreatePostHttpConnection(url.toString()); InputStream input = null; if (conn.getResponseCode() == 200) { input = conn.getInputStream(); } else { input = conn.getErrorStream(); } vo = JSON.parseObject(new String(HttpClientUtil.readInputStream(input),"utf-8"),AuthToken.class); } catch (Exception e) { log.error("getAuthToken error", e); } return vo; }
HttpClientUtil类
package com.huatek.shebao.util; import java.io.ByteArrayOutputStream; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.ProtocolException; import java.net.URL; public class HttpClientUtil { // 设置body体 public static void setBodyParameter(String sb, HttpURLConnection conn) throws IOException { DataOutputStream out = new DataOutputStream(conn.getOutputStream()); out.writeBytes(sb); out.flush(); out.close(); } // 添加签名header public static HttpURLConnection CreatePostHttpConnection(String uri) throws MalformedURLException, IOException, ProtocolException { URL url = new URL(uri); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setUseCaches(false); conn.setDoInput(true); conn.setDoOutput(true); conn.setRequestMethod("POST"); conn.setInstanceFollowRedirects(true); conn.setConnectTimeout(30000); conn.setReadTimeout(30000); conn.setRequestProperty("Content-Type","application/json"); conn.setRequestProperty("Accept-Charset", "utf-8"); conn.setRequestProperty("contentType", "utf-8"); return conn; } public static byte[] readInputStream(InputStream inStream) throws Exception { ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while ((len = inStream.read(buffer)) != -1) { outStream.write(buffer, 0, len); } byte[] data = outStream.toByteArray(); outStream.close(); inStream.close(); return data; } }
封装AuthToken的VO类