RestTemplate -springwebclient

1 使用jar版本 - spring-web-4.3.8.RELEASE.jar

　　场景：backend，post请求远端，header中加入accessToken，用于权限控制　

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
        headers.set("accessToken","70379b6968bf85e95819f119c74559c");

        HttpEntity entity = new HttpEntity<>(headers);
        ResponseEntity<Object> result = restTemplate.postForEntity(url, entity,Object.class);

        int httpStatusCode = result.getStatusCodeValue();
        Object body = result.getBody();
        logger.debug("%s. 取得返回值, httpResponseStatusCode: %s, httpResponseBody: %s",logTitle, httpStatusCode, body);

        String bodyString = JSON.toJSONString(body);
        logger.debug("%s. 返回结果, bodyString: %s", logTitle, bodyString);

map参数：

 使用jar版本 - spring-core-4.3.8.RELEASE.jar

        MultiValueMap<String, String> bodyMap = new LinkedMultiValueMap<>();
        bodyMap.add("username", request.username);
        bodyMap.add("timestamp", request.timestamp);
        bodyMap.add("data", JSON.toJSONString(request.data));

        ResponseEntity<Object> result = restTemplate.postForEntity(url, bodyMap, Object.class);
        int httpStatusCode = result.getStatusCodeValue();
        Object body = result.getBody();
        

2 总结

　　a) RestTemplate 本身也是一个 wrapper 其底层默认是 SimpleClientHttpRequestFactory -> this implementation that uses standard JDK facilities

   　b) 关于返回值是 ResponseEntity<T>  

      c) map为 LinkedMultiValueMap ，不能是hashmap（？）

      d)RestTemplate 有异步版本 AsyncRestTemplate

      e) LinkedMultiValueMap 部分源码 ,存储多value，使用LinkedHashMap 实现，其中value 使用List

public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializable, Cloneable {

   private static final long serialVersionUID = 3801124242820219131L;

   private final Map<K, List<V>> targetMap;


   /**
    * Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap}.
    */
   public LinkedMultiValueMap() {
      this.targetMap = new LinkedHashMap<K, List<V>>();
   }
}