如何使用Spring4.x创建REST端点服务消费者multipart？

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>4.x.x</version>
</dependency>

import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.http.HttpEntity;
import org.springframework.http.MediaType;
import org.springframework.http.HttpHeaders;
import org.springframework.web.client.RestTemplate;
import org.springframework.core.io.FileSystemResource;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

public class RestClient {
    public static void main(String[] args) {
        String url = "http://example.com/api/endpoint"; // 替换为实际的REST端点URL

        // 创建RestTemplate对象
        RestTemplate restTemplate = new RestTemplate();

        // 创建请求头
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);

        // 创建请求体
        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();
        body.add("file", new FileSystemResource("/path/to/file")); // 替换为实际的文件路径

        // 创建HttpEntity对象，包含请求头和请求体
        HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);

        // 发送POST请求
        ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.POST, requestEntity, String.class);

        // 获取响应结果
        String response = responseEntity.getBody();
        System.out.println(response);
    }
}