Our REST APIs are returning results in Pages. Here is an example of one Controller
@RequestMapping(value = "/search", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE + ";charset=UTF-8")
@ResponseStatus(HttpStatus.OK)
public Page<MyObject> findAll(Pageable pageable) {
...
}
Is there an easy way to consume that API with RestTemplate?
if we do
ParameterizedTypeReference<Page<MyObject>> responseType = new ParameterizedTypeReference<Page<MyObject>>() { };
ResponseEntity<Page<MyObject>> result = restTemplate.exchange(url, HttpMethod.GET, null/*httpEntity*/, responseType);
List<MyObject> searchResult = result.getBody().getContent();
it throws an exception
org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: Can not construct instance of org.springframework.data.domain.Page,
problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information at [Source: java.io.PushbackInputStream@3be1e1f2; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of org.springframework.data.domain.Page, problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information
Thank you in advance
Changed the code reading the Rest API response as;
ParameterizedTypeReference<RestResponsePage<MyObject>> responseType = new ParameterizedTypeReference<RestResponsePage<MyObject>>() { };
ResponseEntity<RestResponsePage<MyObject>> result = restTemplate.exchange(url, HttpMethod.GET, null/*httpEntity*/, responseType);
List<MyObject> searchResult = result.getBody().getContent();
And here is the class I created for RestResponsePage
package com.basf.gb.cube.seq.vaadinui.util;
import java.util.ArrayList;
import java.util.List;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;
public class RestResponsePage<T> extends PageImpl<T>{
private static final long serialVersionUID = 3248189030448292002L;
public RestResponsePage(List<T> content, Pageable pageable, long total) {
super(content, pageable, total);
// TODO Auto-generated constructor stub
}
public RestResponsePage(List<T> content) {
super(content);
// TODO Auto-generated constructor stub
}
/* PageImpl does not have an empty constructor and this was causing an issue for RestTemplate to cast the Rest API response
* back to Page.
*/
public RestResponsePage() {
super(new ArrayList<T>());
}
}