java.lang.IllegalArgumentException:在JUnit中模拟restTemplate.exhange时需要HttpMethod (post调用)

import org.junit.Before;
import org.junit.Test;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.test.web.client.MockRestServiceServer;
import org.springframework.web.client.RestTemplate;

import static org.springframework.test.web.client.match.MockRestRequestMatchers.*;
import static org.springframework.test.web.client.response.MockRestResponseCreators.*;

public class RestTemplateTest {

    private RestTemplate restTemplate;
    private MockRestServiceServer mockServer;

    @Before
    public void setup() {
        restTemplate = new RestTemplate();
        mockServer = MockRestServiceServer.createServer(restTemplate);
    }

    @Test
    public void testPostRequest() {
        String url = "http://example.com/api";
        String requestBody = "request body";

        mockServer.expect(requestTo(url))
                .andExpect(method(HttpMethod.POST))
                .andRespond(withSuccess("response body", MediaType.TEXT_PLAIN));

        restTemplate.exchange(url, HttpMethod.POST, requestBody, String.class);

        mockServer.verify();
    }
}