我也尝试过类似的东西，RoboSpice的例子帮助我解决了这个问题:

HttpHeaders headers = new HttpHeaders();
headers.set("Accept", "application/json");

HttpEntity<String> request = new HttpEntity<>(input, createHeader());

String url = "http://awesomesite.org";
Uri.Builder uriBuilder = Uri.parse(url).buildUpon();
uriBuilder.appendQueryParameter(key, value);
uriBuilder.appendQueryParameter(key, value);
...

String url = uriBuilder.build().toString();

HttpEntity<String> response = restTemplate.exchange(url, HttpMethod.GET, request , String.class);

我真是个白痴，我把查询参数和url参数搞混了。我有点希望有一个更好的方式来填充我的查询参数，而不是一个丑陋的连接字符串，但我们有。这只是一个用正确的参数构建URL的例子。如果你把它作为一个字符串传递，Spring也会为你处理编码。

public static void main(String[] args) {
         HttpHeaders httpHeaders = new HttpHeaders();
         httpHeaders.set("Accept", MediaType.APPLICATION_JSON_VALUE);
         final String url = "https://host:port/contract/{code}";
         Map<String, String> params = new HashMap<String, String>();
         params.put("code", "123456");
         HttpEntity<?> httpEntity  = new HttpEntity<>(httpHeaders); 
         RestTemplate restTemplate  = new RestTemplate();
         restTemplate.exchange(url, HttpMethod.GET, httpEntity,String.class, params);
    }

    String uri = http://my-rest-url.org/rest/account/{account};

    Map<String, String> uriParam = new HashMap<>();
    uriParam.put("account", "my_account");

    UriComponents builder = UriComponentsBuilder.fromHttpUrl(uri)
                .queryParam("pageSize","2")
                        .queryParam("page","0")
                        .queryParam("name","my_name").build();

    HttpEntity<String> requestEntity = new HttpEntity<>(null, getHeaders());

    ResponseEntity<String> strResponse = restTemplate.exchange(builder.toUriString(),HttpMethod.GET, requestEntity,
                        String.class,uriParam);

    //final URL: http://my-rest-url.org/rest/account/my_account?pageSize=2&page=0&name=my_name

RestTemplate:使用UriComponents (URI变量和请求参数)构建动态URI

还有一个解决方法:

private String execute(String url, Map<String, String> params) {
    UriComponentsBuilder uriBuilder = UriComponentsBuilder.fromUriString(url)
    // predefined params
            .queryParam("user", "userValue")
            .queryParam("password", "passwordValue");
    params.forEach(uriBuilder::queryParam);
    HttpHeaders headers = new HttpHeaders() {{
        setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        setAccept(List.of(MediaType.APPLICATION_JSON));
    }};
    ResponseEntity<String> request = restTemplate.exchange(uriBuilder.toUriString(), 
                HttpMethod.GET, new HttpEntity<>(headers), String.class);
    return request.getBody();

}

至少从Spring 3开始，许多RestTemplate方法不是使用UriComponentsBuilder来构建URL(这有点啰嗦)，而是在参数路径中接受占位符(不仅仅是交换)。

从文档中可以看到:

Many of the RestTemplate methods accepts a URI template and URI template variables, either as a String vararg, or as Map<String,String>. For example with a String vararg: restTemplate.getForObject( "http://example.com/hotels/{hotel}/rooms/{room}", String.class, "42", "21"); Or with a Map<String, String>: Map<String, String> vars = new HashMap<>(); vars.put("hotel", "42"); vars.put("room", "21"); restTemplate.getForObject("http://example.com/hotels/{hotel}/rooms/{room}", String.class, vars);

参考:https://docs.spring.io/spring/docs/current/spring-framework-reference/integration.html # rest-resttemplate-uri

如果你查看JavaDoc for RestTemplate并搜索“URI Template”，你可以看到哪些方法可以使用占位符。