[网络协议]使用RestTemplate时遇到 http 411 length required 问题

问题：近期在使用RestTemplate请求第三方接口时返回?http 411 length required，但postman测试正常。

解决：根据请求参数的大小，手动在RestTemplate设置了请求头ContentLength的长度

headers.setContentLength(jsonObject.toJSONString().getBytes().length);

代码示例如下：

private void setSessionId() throws RuntimeException {
    JSONObject jsonObject = new JSONObject();
    jsonObject.put("name", username);
    jsonObject.put("password", password);
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
    headers.setContentLength(jsonObject.toJSONString().getBytes().length);
    HttpEntity<JSONObject> httpEntity = new HttpEntity<>(jsonObject, headers);
    ResponseEntity<JSONObject> responseEntity = restTemplate.postForEntity(loginUrl, httpEntity, JSONObject.class);
    if (responseEntity.getStatusCode().is2xxSuccessful()) {
        JSONObject body = responseEntity.getBody();
        assert body != null;
        sessionId = body.getString("session_id");
        log.info("登录接口返回session_id:" + JSONObject.toJSONString(body.getString("session_id")));
    } else {
        throw new RuntimeException("获取session_id失败！");
    }
}