异常：java.security.cert.CertificateException: No subject alternative DNS name matching api.weixin.qq.com found.


代码如下：
try {
URL realUrl = new URL(url);
HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
// 设置为GET方式
connection.setRequestMethod("GET");
// 设置通用的请求属性
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
connection.connect();
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
// 得到响应消息
String message = connection.getResponseMessage();
in = new BufferedReader(new InputStreamReader(connection.getInputStream()));


String line;
String responseJson="";
while ((line = in.readLine()) != null) {
responseJson += line;
}
ObjectMapper mapper = new ObjectMapper();
JsonNode rootNode = mapper.readTree(responseJson); // 读取Json
openid =rootNode.path("openid").asText();
}
// System.out.println("openid:"+openid);
return openid;
}catch (Exception e) {
throw new UserException("no internet："+e.getMessage());
}