Spring RestTemplate GET with parameters

To easily manipulate URLs / path / params / etc., you can use Spring's UriComponentsBuilder class to create a URL template with placehoders for the parameters, then provide the value for those parameters in the RestOperations.exchange(...) call. It's cleaner than manually concatenating strings and it takes care of the URL encoding for you:

HttpHeaders headers = new HttpHeaders();
headers.set(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE);
HttpEntity<?> entity = new HttpEntity<>(headers);

String urlTemplate = UriComponentsBuilder.fromHttpUrl(url)
        .queryParam("msisdn", "{msisdn}")
        .queryParam("email", "{email}")
        .queryParam("clientVersion", "{clientVersion}")
        .queryParam("clientType", "{clientType}")
        .queryParam("issuerName", "{issuerName}")
        .queryParam("applicationName", "{applicationName}")
        .encode()
        .toUriString();

Map<String, ?> params = new HashMap<>();
params.put("msisdn", msisdn);
params.put("email", email);
params.put("clientVersion", clientVersion);
params.put("clientType", clientType);
params.put("issuerName", issuerName);
params.put("applicationName", applicationName);

HttpEntity<String> response = restOperations.exchange(
        urlTemplate,
        HttpMethod.GET,
        entity,
        String.class,
        params
);

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The uriVariables are also expanded in the query string. For example, the following call will expand values for both, account and name:

restTemplate.exchange("http://my-rest-url.org/rest/account/{account}?name={name}",
    HttpMethod.GET,
    httpEntity,
    clazz,
    "my-account",
    "my-name"
);

so the actual request url will be

http://my-rest-url.org/rest/account/my-account?name=my-name

Look at HierarchicalUriComponents.expandInternal(UriTemplateVariables) for more details. Version of Spring is 3.1.3.

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Since at least Spring 3, instead of using UriComponentsBuilder to build the URL (which is a bit verbose), many of the RestTemplate methods accept placeholders in the path for parameters (not just exchange).

From the documentation:

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

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

If you look at the JavaDoc for RestTemplate and search for "URI Template", you can see which methods you can use placeholders with.

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OK, so I'm being an idiot and I'm confusing query parameters with url parameters. I was kinda hoping there would be a nicer way to populate my query parameters rather than an ugly concatenated String but there we are. It's simply a case of build the URL with the correct parameters. If you pass it as a String Spring will also take care of the encoding for you.

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    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: Build dynamic URI using UriComponents (URI variable and Request parameters)

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I was attempting something similar, and the RoboSpice example helped me work it out:

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);

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Converting of a hash map to a string of query parameters:

Map<String, String> params = new HashMap<>();
params.put("msisdn", msisdn);
params.put("email", email);
params.put("clientVersion", clientVersion);
params.put("clientType", clientType);
params.put("issuerName", issuerName);
params.put("applicationName", applicationName);

UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(url);
for (Map.Entry<String, String> entry : params.entrySet()) {
    builder.queryParam(entry.getKey(), entry.getValue());
}

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

HttpEntity<String> response = restTemplate.exchange(builder.toUriString(), HttpMethod.GET, new HttpEntity(headers), String.class);

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In Spring Web 4.3.6 I also see

public <T> T getForObject(String url, Class<T> responseType, Object... uriVariables)

That means you don't have to create an ugly map

So if you have this url

http://my-url/action?param1={param1}&param2={param2}

You can either do

restTemplate.getForObject(url, Response.class, param1, param2)

or

restTemplate.getForObject(url, Response.class, param [])

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I take different approach, you may agree or not but I want to control from .properties file instead of compiled Java code

Inside application.properties file

endpoint.url = https://yourHost/resource?requestParam1={0}&requestParam2={1}

Java code goes here, you can write if or switch condition to find out if endpoint URL in .properties file has @PathVariable (contains {}) or @RequestParam (yourURL?key=value) etc... then invoke method accordingly... that way its dynamic and not need to code change in future one stop shop...

I'm trying to give more of idea than actual code here ...try to write generic method each for @RequestParam, and @PathVariable etc... then call accordingly when needed

  @Value("${endpoint.url}")
  private String endpointURL;
  // you can use variable args feature in Java
  public String requestParamMethodNameHere(String value1, String value2) {
    RestTemplate restTemplate = new RestTemplate();
    restTemplate
           .getMessageConverters()
           .add(new MappingJackson2HttpMessageConverter());

    HttpHeaders headers = new HttpHeaders();
    headers.set("Accept", MediaType.APPLICATION_JSON_VALUE);
    HttpEntity<String> entity = new HttpEntity<>(headers);

    try {
      String formatted_URL = MessageFormat.format(endpointURL, value1, value2);
      ResponseEntity<String> response = restTemplate.exchange(
                    formatted_URL ,
                    HttpMethod.GET,
                    entity,
                    String.class);
     return response.getBody();
    } catch (Exception e) { e.printStackTrace(); }

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If you pass non-parametrized params for RestTemplate, you'll have one Metrics for everyone single different URL that you pass, considering the parameters. You would like to use parametrized urls:

http://my-url/action?param1={param1}&param2={param2}

instead of

http://my-url/action?param1=XXXX&param2=YYYY

The second case is what you get by using UriComponentsBuilder class.

One way to implement the first behavior is the following:

Map<String, Object> params = new HashMap<>();
params.put("param1", "XXXX");
params.put("param2", "YYYY");

String url = "http://my-url/action?%s";

String parametrizedArgs = params.keySet().stream().map(k ->
    String.format("%s={%s}", k, k)
).collect(Collectors.joining("&"));

HttpHeaders headers = new HttpHeaders();
headers.set("Accept", MediaType.APPLICATION_JSON_VALUE);
HttpEntity<String> entity = new HttpEntity<>(headers);

restTemplate.exchange(String.format(url, parametrizedArgs), HttpMethod.GET, entity, String.class, params);

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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);
    }

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I am providing a code snippet of RestTemplate GET method with path param example

public ResponseEntity<String> getName(int id) {
    final String url = "http://localhost:8080/springrestexample/employee/name?id={id}";
    Map<String, String> params = new HashMap<String, String>();
    params.put("id", id);
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    HttpEntity request = new HttpEntity(headers);
    ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.GET, String.class, params);
    return response;
}

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You can use follow code for String.

URL_EXAMPLE="http://{domain}/Index.php?Username={user}&password={password}";

String domain = "example.com";
String user = "user";
String password = "password";

String data=this.restTemplate.getForObject(URL_EXAMPLE,String.class,domain,user,password);

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If your url is http://localhost:8080/context path?msisdn={msisdn}&email={email}

then

Map<String,Object> queryParams=new HashMap<>();
queryParams.put("msisdn",your value)
queryParams.put("email",your value)

works for resttemplate exchange method as described by you

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hi i build url with query params using this code:

UriComponentsBuilder.fromHttpUrl(url)
                .queryParam("bikerPhoneNumber", "phoneNumberString")
                .toUriString();

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