Java客户端服务端上传接收文件实现详解

// 引入pom依赖, hutool相关文档, https://www.hutool.cn/docs/
<dependency>
  <groupId>cn.hutool</groupId>
  <artifactId>hutool-all</artifactId>
  <version>5.3.7</version>
</dependency>

HashMap<String, Object> paramMap = new HashMap<>();
//文件上传只需将参数中的键指定（默认file），值设为文件对象即可，对于使用者来说，文件上传与普通表单提交并无区别
paramMap.put("file", FileUtil.file("C:\\文件路径\\文件名称"));
String result = HttpUtil.post("服务端IP:端口", paramMap);

public class Utils {
  public static void saveFile( MultipartFile filecontent){
    OutputStream os = null;
    InputStream inputStream = null;
    String fileName = null;
    try {
      inputStream = filecontent.getInputStream();
      fileName = filecontent.getOriginalFilename();
    } catch (IOException e) {
      e.printStackTrace();
    }
    try {
      String path = "C:\\test\\";
      // 2、保存到临时文件
      // 1K的数据缓冲
      byte[] bs = new byte[1024];
      // 读取到的数据长度
      int len;
      // 输出的文件流保存到本地文件
      File tempFile = new File(path);
      if (!tempFile.exists()) {
        tempFile.mkdirs();
      }
      os = new FileOutputStream(tempFile.getPath() + File.separator + fileName);
      // 开始读取
      while ((len = inputStream.read(bs)) != -1) {
        os.write(bs, 0, len);
      }
    } catch (IOException e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      // 完毕，关闭所有链接
      try {
        os.close();
        inputStream.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
}

@Controller
public class FileController {
  @RequestMapping("/")
  @ResponseBody
  public String index(@RequestParam(value = "file", required = false) MultipartFile file, HttpServletRequest request, HttpServletResponse response) throws IOException {
    Utils.saveFile(file);
    return "Success";
  }
}