微信公众号OAuth 点击菜单按钮 跳转页面授权 获取openid

流程：

用户点击菜单按钮

—–> 发送页面授权请求到微信后台

—–>得到code发送到 我们服务器后台的url

—–> 将code参数发送到微信后台获取用户的openid返回服务器上的页面(也可以直接获取用户头像等基本信息。。需用户点击同意授权)

菜单view按钮的url：

“https://open.weixin.qq.com/connect/oauth2/authorize?appid=“+yourAppid+”&redirect_uri=”+你要跳转的url+”&response_type=code&scope=snsapi_base&state=1#wechat_redirect”

详情请见官方文档

http://mp.weixin.qq.com/wiki/17/c0f37d5704f0b64713d5d2c37b468d75.html

你要跳转的url 请求到后台 获取页面授权的code

String code = request.getParameter("code");// 页面授权获取的code用以交换openid额access_token
openid = OAuthGetOpenid(code);// OAuth获取用户openid区分是哪个用户请求登录W3

/**
* 通过页面OAuth授权,用code获取openid
*
* @param code
* @return
*/
public String OAuthGetOpenid(String code) {
JSONObject json = new JSONObject();
String requestUrl = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=你的公众号id&secret=你的公众号密码&code=" + code + "&grant_type=authorization_code";
String outputStr = "";
new HttpRequestPost();
json = HttpRequestPost.httpRequest(requestUrl, outputStr, "POST");
String openid = json.getString("openid");
return openid;
}

发送http请求的方法代码

/***
* 向微信端发送post请求
*
*/
public class HttpRequestPost {

public static JSONObject httpRequest(String requestUrl, String outputStr, String method) {
JSONObject jsonObject = null;
StringBuffer buffer = new StringBuffer();
try {
// // 创建SSLContext对象，并使用我们指定的信任管理器初始化
// TrustManager[] tm = { new MyX509TrustManager() };
// SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
// sslContext.init(null, tm, new java.security.SecureRandom());
// 从上述SSLContext对象中得到SSLSocketFactory对象
// SSLSocketFactory ssf = sslContext.getSocketFactory();

URL url = new URL(requestUrl);
HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();
// httpUrlConn.setSSLSocketFactory(ssf);

httpUrlConn.setDoOutput(true);
httpUrlConn.setDoInput(true);
httpUrlConn.setUseCaches(false);
// 设置请求方式（GET/POST）
httpUrlConn.setRequestMethod(method);
httpUrlConn.connect();

// 当有数据需要提交时
if (null != outputStr) {
OutputStream outputStream = httpUrlConn.getOutputStream();
// 注意编码格式，防止中文乱码
outputStream.write(outputStr.getBytes("UTF-8"));
outputStream.close();
}
// 将返回的输入流转换成字符串
InputStream inputStream = httpUrlConn.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

String str = null;
while ((str = bufferedReader.readLine()) != null) {
buffer.append(str);
}
bufferedReader.close();
inputStreamReader.close();
// 释放资源
inputStream.close();
inputStream = null;
httpUrlConn.disconnect();
jsonObject = JSONObject.fromObject(buffer.toString());
System.out.println("http-back:" + jsonObject);
} catch (ConnectException ce) {
System.err.println("Weixin server connection timed out.");
} catch (Exception e) {
System.err.println("https request error:{}" + e);
}
return jsonObject;
}
}