带请求参数的 RestTemplate GET 请求

Question

我必须调用 REST Web 服务，并且我计划使用 RestTemplate。我查看了有关如何发出 GET 请求的示例，如下所示。

 String result = restTemplate.getForObject("http://example.com/hotels/{hotel}/bookings/{booking}", String.class,"42","21");

就我而言，RESTful url 如下所示。在这种情况下我该如何使用 RestTemplate？

http://example.com/hotels?state=NY&country=USA

所以我的问题是如何发送 GET 请求的请求参数？

Answer 1

在向 RESTful 服务器发出请求时，在许多情况下需要发送查询参数、请求正文（在 POST 和 PUT 请求方法的情况下）以及向服务器发出的请求中的标头。

在这种情况下，可以使用 UriComponentsBuilder.build()，使用UriComponents。如果需要，请进行编码（），并使用 RestTemplate.exchange() 像这样：

public ResponseEntity<String> requestRestServerWithGetMethod()
{
    HttpEntity<?> entity = new HttpEntity<>(requestHeaders); // requestHeaders is of HttpHeaders type
    UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(rawValidUrl) // rawValidURl = http://example.com/hotels
            .queryParams(
                    (LinkedMultiValueMap<String, String>) allRequestParams); // The allRequestParams must have been built for all the query params
    UriComponents uriComponents = builder.build().encode(); // encode() is to ensure that characters like {, }, are preserved and not encoded. Skip if not needed.
    ResponseEntity<Object> responseEntity = restTemplate.exchange(uriComponents.toUri(), HttpMethod.GET,
            entity, String.class);
    return responseEntity;
}

public ResponseEntity<String> requestRestServerWithPostMethod()
{
    HttpEntity<?> entity = new HttpEntity<>(requestBody, requestHeaders); // requestBody is of string type and requestHeaders is of type HttpHeaders
    UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(rawValidUrl) // rawValidURl = http://example.com/hotels
            .queryParams(
                    (LinkedMultiValueMap<String, String>) allRequestParams); // The allRequestParams must have been built for all the query params
    UriComponents uriComponents = builder.build().encode(); // encode() is to ensure that characters like {, }, are preserved and not encoded. Skip if not needed.
    ResponseEntity<Object> responseEntity = restTemplate.exchange(uriComponents.toUri(), HttpMethod.POST,
            entity, String.class);
    return responseEntity;
}

Answer 2

占位符对于任何类型的 url 的工作方式都是相同的，只是

 String result = restTemplate.getForObject("http://example.com/hotels?state={state}&country={country}", String.class,"NY","USA");

这样做或者更好，使用哈希图进行实名匹配 -