使用Spring的RestTemplate以块的形式发送文件

import org.springframework.http.*;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class FileUploadExample {
    public static void main(String[] args) throws IOException {
        String url = "http://example.com/upload"; // 目标URL

        // 创建MultiValueMap对象
        MultiValueMap<String, Object> body = new LinkedMultiValueMap<>();

        // 读取文件内容并添加到MultiValueMap中
        File file = new File("path/to/file");
        FileInputStream fileInputStream = new FileInputStream(file);
        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = fileInputStream.read(buffer)) != -1) {
            body.add("file", new ByteArrayResource(buffer, 0, bytesRead), file.getName());
        }

        // 创建HttpHeaders对象
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);

        // 创建HttpEntity对象
        HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(body, headers);

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

        // 发送POST请求
        ResponseEntity<String> response = restTemplate.postForEntity(url, requestEntity, String.class);

        // 处理响应结果
        if (response.getStatusCode() == HttpStatus.OK) {
            System.out.println("文件上传成功");
        } else {
            System.out.println("文件上传失败");
        }
    }
}