用于处理HttpClient进行的文件上载的服务器代码

Question

我有一个Java HttpClient，它执行以下代码：

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://exampleutl.com/upload/");
File file = new File("C:/src_path/binary.doc");
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setMode(HttpMultipartMode.STRICT);
FileBody fileBody = new FileBody(file); //image should be a String
builder.addPart("file", fileBody);
post.setEntity(builder.build());
client.execute(post);

我不知道映射到/upload/path的服务器方法应该是什么样子。

接受此文件上传请求的服务器是Spring 4.0。类似这样的东西：

@RequestMapping(method = RequestMethod.POST, value = "/upload/")
public @ResponseBody String saveUpload(UploadDto dto) throws IOException,ServletException {
    File file = new File("C:/dest_path/" + dto.getFile().getOriginalFilename());
    FileUtils.writeByteArrayToFile(file, dto.getFile().getBytes());
    return "success";
}

上面的服务器方法由client.execute（）调用，但UploadDto为空。这是UploadDto:

public class UploadDto {
    private MultipartFile file;
    public MultipartFile getFile() {
        return file;
    }
    public void setFile(MultipartFile file) {
        this.file = file;
    }
}

如有任何协助，我们将不胜感激！

Answer 1

Spring servlet上下文中似乎缺少一个MultipartResolver bean。类似的东西

@Bean
public MultipartResolver multipartResolver() {
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    return multipartResolver;
}

---

您正在向发送请求

HttpPost post = new HttpPost("http://exampleutl.com/upload/");

假设您的上下文路径是ROOT，即为空，那么您的处理程序方法应该映射到/upload。

@RequestMapping(method = RequestMethod.POST, value = "/upload")

Answer 2

最终的答案是服务器方法应该是这样的：

@RequestMapping(method = RequestMethod.POST, value = "/upload/")
public @ResponseBody String saveUpload(@RequestParam("file") final MultipartFile mpf) throws IOException, ServletException, FileUploadException {
    File file = new File("C:/dest_path/" + mpf.getOriginalFilename());
    FileUtils.writeByteArrayToFile(file, mpf.getBytes());
    return "success";
}

正如Sotirios Delimanis所提到的，MultipartResolver确实也是解决方案的必要组成部分：

@Bean
public MultipartResolver multipartResolver() {
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    return multipartResolver;
}