Spring Boot 3 - RestTemplate and GET method request with body (JSON payload)

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// --------------------------------------------------------------------------------
// Usage example:
// --------------------------------------------------------------------------------

ExtendedRestTemplate restTemplate = new ExtendedRestTemplate();

SomeRequest someRequest = new SomeRequest(1L, "John", "john@email.com");
SomeResponse someResponse = restTemplate.getForObject("http://localhost/api/some-path", someRequest, SomeResponse.class);  // <--- GET method request with body


// See also:
//
//     1. https://dirask.com/snippets/Spring-Boot-3-RestTemplate-with-custom-HTTPS-SSL-certificate-1GM8Yp
//     2. https://dirask.com/snippets/Spring-Boot-3-RestTemplate-with-ignored-HTTPS-SSL-certificate-ignore-untrusted-certificates-1bQZJj



// --------------------------------------------------------------------------------
// ExtendedRestTemplate.java file (it allows to send GET requests with body):
// --------------------------------------------------------------------------------

package com.dirask.example;

import java.net.URI;
import java.util.List;
import java.util.Map;

import org.springframework.http.HttpMethod;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.lang.Nullable;
import org.springframework.web.client.HttpMessageConverterExtractor;
import org.springframework.web.client.RequestCallback;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

public class ExtendedRestTemplate extends RestTemplate {

	public ExtendedRestTemplate() {
		super();
	}

	public ExtendedRestTemplate(ClientHttpRequestFactory requestFactory) {
		super(requestFactory);
	}

	public ExtendedRestTemplate(List<HttpMessageConverter<?>> messageConverters) {
		super(messageConverters);
	}

	@Nullable
	public <T> T getForObject(URI url, @Nullable Object requestObject, Class<T> responseType) throws RestClientException {
		List<HttpMessageConverter<?>> messageConverters = super.getMessageConverters();
		RequestCallback requestCallback = super.httpEntityCallback(requestObject, responseType);
		HttpMessageConverterExtractor<T> responseExtractor = new HttpMessageConverterExtractor<>(responseType, messageConverters);
		return super.execute(url, HttpMethod.GET, requestCallback, responseExtractor);
	}

	@Nullable
	public <T> T getForObject(String url, @Nullable Object requestObject, Class<T> responseType, Object... uriVariables) throws RestClientException {
		List<HttpMessageConverter<?>> messageConverters = super.getMessageConverters();
		RequestCallback requestCallback = httpEntityCallback(requestObject, responseType);
		HttpMessageConverterExtractor<T> responseExtractor = new HttpMessageConverterExtractor<>(responseType, messageConverters);
		return super.execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
	}

	@Nullable
	public <T> T getForObject(String url, @Nullable Object requestObject, Class<T> responseType, Map<String, ?> uriVariables) throws RestClientException {
		List<HttpMessageConverter<?>> messageConverters = super.getMessageConverters();
		RequestCallback requestCallback = super.httpEntityCallback(requestObject, responseType);
		HttpMessageConverterExtractor<T> responseExtractor = new HttpMessageConverterExtractor<>(responseType, messageConverters);
		return super.execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
	}
}