java后端发起https请求时Received fatal alert: protocol_version错误

前段时间项目上明明好好的定时任务，发生了崩溃，好几天的数据都没有获取到。

查了下日志发现大批量的javax.net.ssl.SSLException: Received fatal alert: protocol_version；

原因：

在Java 1.8上，默认TLS协议是v1.2。在Java 1.6和1.7上，默认是已废弃的TLS1.0

这个原因是我能找到的一个可靠的说法，但这个接口以前就是https的，我认为这个三方的服务接口应该是被做了限制。具体怎样的不得而知

解决办法：

平常我们的httpclient请求是这样的

 public static CloseableHttpResponse postHttp(String url) throws Exception{
  CloseableHttpClient httpclient = HttpClients.createDefault();
  HttpPost httpPost = new HttpPost(url);
  CloseableHttpResponse response = null;
  response = httpclient.execute(httpPost);
  return response;
 }

改为，使用TLSv1.2创建httpclient的方式即可，亲测有效

 public static CloseableHttpResponse getHttp(String url) throws Exception{
  SSLContext ctx = SSLContexts.custom().useProtocol("TLSv1.2").build();
  CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(new SSLConnectionSocketFactory(ctx)).build();
  HttpGet httpGet = new HttpGet(url);
  CloseableHttpResponse response = null;
  response = httpClient.execute(httpGet);
  return response;
 }