将文件转换为MultiPartFile

Question

有没有办法将File对象转换为MultiPartFile？这样我就可以将该对象发送给接受MultiPartFile接口对象的方法了？

File myFile = new File("/path/to/the/file.txt")

MultiPartFile ....?

def (MultiPartFile file) {
  def is = new BufferedInputStream(file.getInputStream())
  //do something interesting with the stream
}

Answer 1

MockMultipartFile就是为此而存在的.如在您的代码段中,如果文件路径已知,则以下代码适用于我.

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.springframework.mock.web.MockMultipartFile;

Path path = Paths.get("/path/to/the/file.txt");
String name = "file.txt";
String originalFileName = "file.txt";
String contentType = "text/plain";
byte[] content = null;
try {
    content = Files.readAllBytes(path);
} catch (final IOException e) {
}
MultipartFile result = new MockMultipartFile(name,
                     originalFileName, contentType, content);

Answer 2

这是一种无需在光盘上手动创建文件的解决方案：

MultipartFile fichier = new MockMultipartFile("fileThatDoesNotExists.txt",
            "fileThatDoesNotExists.txt",
            "text/plain",
            "This is a dummy file content".getBytes(StandardCharsets.UTF_8));

Answer 3

    File file = new File("src/test/resources/input.txt");
    FileInputStream input = new FileInputStream(file);
    MultipartFile multipartFile = new MockMultipartFile("file",
            file.getName(), "text/plain", IOUtils.toByteArray(input));

Answer 4

您可以自己实现 MultipartFile。例如：

public class JavaFileToMultipartFile implements MultipartFile {

private final File file;

public TPDecodedMultipartFile(File file) {
    this.file = file;
}

@Override
public String getName() {
    return file.getName();
}

@Override
public String getOriginalFilename() {
    return file.getName();
}

@Override
public String getContentType() {
    try {
        return Files.probeContentType(file.toPath());
    } catch (IOException e) {
        throw new RuntimeException("Error while extracting MIME type of file", e);
    }
}

@Override
public boolean isEmpty() {
    return file.length() == 0;
}

@Override
public long getSize() {
    return file.length();
}

@Override
public byte[] getBytes() throws IOException {
    return Files.readAllBytes(file.toPath());
}

@Override
public InputStream getInputStream() throws IOException {
    return new FileInputStream(file);
}

@Override
public void transferTo(File dest) throws IOException, IllegalStateException {
    throw new UnsupportedOperationException();
}
}

Answer 5

File file = new File("src/test/resources/validation.txt");
DiskFileItem fileItem = new DiskFileItem("file", "text/plain", false, file.getName(), (int) file.length() , file.getParentFile());
fileItem.getOutputStream();
MultipartFile multipartFile = new CommonsMultipartFile(fileItem);

您需要采取以下措施来预防 NPE。

fileItem.getOutputStream();

另外，您需要将文件内容复制到fileItem，这样文件就不会为空

new FileInputStream(f).transferTo(item.getOutputStream());

Answer 6

MultipartFile multipartFile = new MockMultipartFile("test.xlsx", new FileInputStream(new File("/home/admin/test.xlsx")));

这段代码对我来说很好.也许你可以尝试一下.

Answer 7

没有 Mocking 类、仅 Java9+ 和 Spring 的解决方案。

FileItem fileItem = new DiskFileItemFactory().createItem("file",
    Files.probeContentType(file.toPath()), false, file.getName());

try (InputStream in = new FileInputStream(file); OutputStream out = fileItem.getOutputStream()) {
    in.transferTo(out);
} catch (Exception e) {
    throw new IllegalArgumentException("Invalid file: " + e, e);
}

CommonsMultipartFile multipartFile = new CommonsMultipartFile(fileItem);

Answer 8

就我而言，

fileItem.getOutputStream();

没有工作。因此，我是使用IOUtils自己制作的，

File file = new File("/path/to/file");
FileItem fileItem = new DiskFileItem("mainFile", Files.probeContentType(file.toPath()), false, file.getName(), (int) file.length(), file.getParentFile());

try {
    InputStream input = new FileInputStream(file);
    OutputStream os = fileItem.getOutputStream();
    IOUtils.copy(input, os);
    // Or faster..
    // IOUtils.copy(new FileInputStream(file), fileItem.getOutputStream());
} catch (IOException ex) {
    // do something.
}

MultipartFile multipartFile = new CommonsMultipartFile(fileItem);

Answer 9

如果您无法MockMultipartFile使用以下方式导入

import org.springframework.mock.web.MockMultipartFile;

您需要将以下依赖项添加到pom.xml：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>