Spring Web's RestTemplate, exchange. java.util.LinkedHashMap cannot be cast to_resttemplate java.util.linkedhashmap cannot be cas-优快云博客

本文链接：https://blog.youkuaiyun.com/Good_Luck_8/article/details/72736533

本文介绍了一种Java中常用的泛型返回对象ReturnData的设计方法，并展示了如何使用该对象来处理HTTP请求的响应。通过具体的代码实例，读者可以了解如何创建泛型返回对象并将其应用于RESTful API调用。

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public class ReturnData<E> implements Serializable {

    private int code;
    private E data;
    private String msg;

    public ReturnData() {
   }

   public ReturnData(int code, E data, String msg) {
       super();
       this.code = code;
       this.data = data;
       this.msg = msg;
   }
   public int getCode() {
       return code;
   }
   public void setCode(int code) {
       this.code = code;
   }
   public E getData() {
       return data;
   }
   public void setData(E data) {
       this.data = data;
   }
   public String getMsg() {
       return msg;
   }
   public void setMsg(String msg) {
       this.msg = msg;
   }
   @Override
   public String toString() {
       return "ReturnData [code=" + code + ", data=" + data + ", msg=" + msg
               + "]";
   }

}

使用以下的方式来处理：

                ParameterizedTypeReference<ReturnData<User>> typeRef = new ParameterizedTypeReference<ReturnData<User>>() {
               };
               HttpEntity<?> requestEntity = new HttpEntity<Object>(u);
               ResponseEntity<ReturnData<User>> responseEntity = template.exchange(IConstants.USER_LOGIN_URL,
                       HttpMethod.POST, requestEntity, typeRef);
               ReturnData<User> returnData = responseEntity.getBody();