更改MultipartFile的名称

Question

我正在尝试更改 MultipartFile 的名称。

我在控制器上使用 MultipartFile 来调用休息服务：

@PostMapping("/post")
public ResponseEntity<String> handleFileUpload(@RequestParam("file") MultipartFile file)
{
    ...
}

您对更改上传文件的 OriginalFilename 有什么想法吗？

非常感谢。

Answer 1

您可以尝试以下代码。

@PostMapping("/post")
public ResponseEntity<String> handleFileUpload(@RequestParam("file") MultipartFile file)
{
    try {
        String filename = "random_filename.pdf"; // Give a random filename here.
        byte[] bytes = file.getBytes();
        String insPath = <DIRECTORY PATH> + filename // Directory path where you want to save ;
        Files.write(Paths.get(insPath), bytes);

        return ResponseEntity.ok(filename);
    }

    catch (IOException e) {
        // Handle exception here 
    }
}

您必须记住在文件名中添加随机字符串。如果你只是硬编码文件名，那么每次上传文件时，之前的文件都会被替换。

Answer 2

您可以通过如下方式实现文件重命名。要验证，请转到 uploadDir，您将获得一个带有

"renameTest"

的文件。

您可以将

clientId + uploadTime

附加到文件名以避免数据库中出现相同的文件名

@PostMapping(value = "/post")
    public  String renameMultipartFile(@RequestParam("file") MultipartFile file) {
        String uploadDir = "yourPath";
        String filename = "renameTest";
        Path saveTO = Paths.get(uploadDir + filename);
        try {
            try {
                Files.copy(file.getInputStream(), saveTO);
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException("Error : " + e.getMessage());
            }
            return "File uploaded successfully";
        } catch (Exception e) {
            e.printStackTrace();
            return "Error : " + e.getMessage();
        }
    }

Answer 3

如果您将文件“转发”到另一台服务器，您可以尝试以下代码：

import jakarta.validation.constraints.NotNull;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URL;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.Charset;

public class MultipartFileResourceNameDecorator implements Resource {
    private final Resource resource;
    private final String newFileName;


    public MultipartFileResourceNameDecorator(@NotNull Resource resource, @NotNull String newFileName) {
        this.resource = resource;
        this.newFileName = newFileName;
    }

    @Override
    @Nullable
    public String getFilename() {
        return newFileName;
    }

    // delegate another methods
}

来电者：

private String sendByFile(Resource fileResource, String newFileName) {
    var resource = new MultipartFileResourceNameDecorator(fileResource, newFileName);
    log.info("Upload file: {}", resource.getFilename());
    try {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
        // Create the request body with the file
        var body = new LinkedMultiValueMap<String, Object>();
        body.add("file", resource);
        // Create the HttpEntity
        var entity = new HttpEntity<>(body, headers);
        // Make the POST request
        var response = restTemplate.postForEntity(urlUpload, entity, String.class);
        
        // Your logic here with response
        
    } catch (Exception e) {
        log.error("Upload fail", e);
        return null;
    }
}