When requesting resttemplate, set the request header, request parameters, and request body.

public static <T> ResponseEntity<T> request(String url,
                                            HttpMethod httpMethod,
                                            Class<T> responseType,
                                            Map<String,String> headers,
                                            Map<String,String> params,
                                            Map<String,String> body) {
    

        // Set request parameters 
        MultiValueMap<String, String> paramsMap = new LinkedMultiValueMap<>();

        if(CollUtil.isNotEmpty(params)){
    
            params.forEach(paramsMap::add);
        }

        UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
        URI uri = builder.queryParams(paramsMap).build().encode().toUri();

        //  Set request header 
        HttpHeaders httpHeaders = new HttpHeaders();
        //  Must be set when passing the request body 
        httpHeaders.add("Content-Type", "application/json");

        if( CollUtil.isNotEmpty(headers) ){
    
            headers.forEach(httpHeaders::add);
        }

        //  Set request header and request body 
        HttpEntity<String> httpEntity = new HttpEntity<>(JSONUtil.toJsonStr(body), httpHeaders);

        return restTemplate.exchange(uri,httpMethod,httpEntity,responseType);
    }