我的用户可以在我的服务器上发布食物照片和食物内容的帖子。
例如，假设有人看到美味的东西，拍下它的照片，然后写下“好吃的！”＃34;在图片下面。照片被发送到服务器，消息＆＃34;美味！＆＃34;包括用户名，日期，位置等在一个名为＆＃34; Post＆＃34;的对象中发送。使用一个api调用到我的服务器。
我在android端编写了以下代码：
final String url = Constants.POST_PICS;
RestTemplate restTemplate = RestClientConfig.getRestTemplate(context, true);
//adding StringHttpMessageConverter, formHttpMessageConverter and MappingJackson2HttpMessageConverter to restTemplate
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
FormHttpMessageConverter formHttpMessageConverter = new FormHttpMessageConverter();
restTemplate.getMessageConverters().add(formHttpMessageConverter);
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
//putting both objects into a map
MultiValueMap<String, Object> map = new LinkedMultiValueMap<String, Object>();
map.add("image", new FileSystemResource(file));
map.add("post", post);
HttpHeaders imageHeaders = new HttpHeaders();
//setting content type to multipart as the image is a multipart file
imageHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
HttpEntity<MultiValueMap<String, Object>> imageEntity = new HttpEntity<MultiValueMap<String, Object>>(map, imageHeaders);
ResponseEntity<Post> response = restTemplate.exchange(url, HttpMethod.POST, imageEntity, Post.class);
return response.getBody();
这是Spring方面的代码：
@RequestMapping(value = "/uploadpostpic", method = RequestMethod.POST)
public Post uploadPostWithPic(@RequestParam("image") MultipartFile srcFile,
@RequestParam("post") Post post) {
return serviceGateway.uploadPostWithPic(srcFile, post);
}
我收到错误：
请求网络执行期间发生异常：无法执行 写请求：没有为请求类型找到合适的HttpMessageConverter [Model.Post]
org.springframework.http.converter.HttpMessageNotWritableException： 无法写入请求：找不到合适的HttpMessageConverter 请求类型[Model.Post]
我怀疑它与设置为MULTIPART_FORM_DATA的内容类型有关，但我需要将其设置为此，因为我需要将图片传输到服务器。
是否可以同时使用restTemplate传输多部分文件和另一个上游对象？
编辑：
我看过这些帖子：
Resttemplate form/multipart: image + JSON in POST
Sending Multipart File as POST parameters with RestTemplate requests
并根据他们的指导尝试了这段代码：
final String url = Constants.POST_PIC;
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
restTemplate.getMessageConverters().add(new ByteArrayHttpMessageConverter());
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
restTemplate.getMessageConverters().add(new ResourceHttpMessageConverter());
FormHttpMessageConverter formHttpMessageConverter = new FormHttpMessageConverter();
formHttpMessageConverter.addPartConverter(new MappingJackson2HttpMessageConverter());
formHttpMessageConverter.addPartConverter(new ResourceHttpMessageConverter()); // This is hope driven programming
formHttpMessageConverter.addPartConverter(new ByteArrayHttpMessageConverter());
restTemplate.getMessageConverters().add(formHttpMessageConverter);
MultiValueMap<String, Object> multipartRequest = new LinkedMultiValueMap<>();
byte[] bFile = new byte[(int) imageFile.length()];
FileInputStream fileInputStream;
//convert file into array of bytes
fileInputStream = new FileInputStream(imageFile);
fileInputStream.read(bFile);
fileInputStream.close();
ByteArrayResource bytes = new ByteArrayResource(bFile) {
@Override
public String getFilename() {
return "file.jpg";
}
};
//post portion of the multipartRequest
HttpHeaders xHeader = new HttpHeaders();
xHeader.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<Post> xPart = new HttpEntity<>(post, xHeader);
multipartRequest.add("post", xPart);
//picture portion of the multipartRequest
HttpHeaders pictureHeader = new HttpHeaders();
pictureHeader.setContentType(MediaType.IMAGE_JPEG);
HttpEntity<ByteArrayResource> picturePart = new HttpEntity<>(bytes, pictureHeader);
multipartRequest.add("srcFile", picturePart);
//adding both the post and picture portion to one httpentity for transmitting to server
HttpHeaders header = new HttpHeaders();
header.setContentType(MediaType.MULTIPART_FORM_DATA);
HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity(multipartRequest, header);
return restTemplate.postForObject(url, requestEntity, Post.class);
另一方面，post = null，我不知道为什么它为null。
这就是我在服务器端试图做的所有事情：
public Post uploadPostPic(MultipartFile srcFile, Post post) {
Post savedPost = repo.save(post);
}
我将其保存到我的存储库中，错误是：
java.lang.IllegalArgumentException: Entity must not be null!
答案 0 :(得分：1)
尝试这样的事情： 在这里发送jsonString，然后使用objectwriter将其转换为对象。让我知道您是否需要更多解释。
@RequestMapping(value = "/uploadMultipleFile", method = RequestMethod.POST)
public @ResponseBody
String uploadMultipleFileHandler(@RequestParam("name") String[] names,
@RequestParam("file") MultipartFile[] files) {
if (files.length != names.length)
return "Mandatory information missing";
String message = "";
for (int i = 0; i < files.length; i++) {
MultipartFile file = files[i];
String name = names[i];
try {
byte[] bytes = file.getBytes();
// Creating the directory to store file
String rootPath = System.getProperty("catalina.home");
File dir = new File(rootPath + File.separator + "tmpFiles");
if (!dir.exists())
dir.mkdirs();
// Create the file on server
File serverFile = new File(dir.getAbsolutePath()
+ File.separator + name);
BufferedOutputStream stream = new BufferedOutputStream(
new FileOutputStream(serverFile));
stream.write(bytes);
stream.close();
logger.info("Server File Location="
+ serverFile.getAbsolutePath());
message = message + "You successfully uploaded file=" + name
+ "<br />";
} catch (Exception e) {
return "You failed to upload " + name + " => " + e.getMessage();
}
}
return message;
}
}
<强>编辑：
最终，我不得不使用jsonString来解决我的问题。这不是理想的，因为网址最终变得很长，但这是解决我问题的最快方法：
请查看mykong关于如何将对象转换为jsonString并将其重新转换回对象的建议：
ObjectMapper mapper = new ObjectMapper();
Staff obj = new Staff();
//Object to JSON in String
String jsonInString = mapper.writeValueAsString(obj);
//JSON from String to Object
Staff obj = mapper.readValue(jsonInString, Staff.class);
http://www.mkyong.com/java/jackson-2-convert-java-object-to-from-json/
答案 1 :(得分：0)
我没有为你的Post类看到一个注册的HttpMessageConverter。您可能必须为MultiValueMap注册一个HttpMessageConverter。
答案 2 :(得分：0)
multipart/form-data内容类型的含义：
“multipart / form-data”消息包含一系列部分 代表一个成功的控制。
成功的控制对于提交是“有效的”。每一次成功 control的控制名称与其当前值配对 提交的表单数据集
简单来说，使用多部分表单数据，您可以向服务器发送不同内容类型的数据。这是一个样本：
POST / HTTP/1.1
Host: localhost:8000
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:29.0) Gecko/20100101 Firefox/29.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Cookie: __atuvc=34%7C7; permanent=0; _gitlab_session=226ad8a0be43681acf38c2fab9497240; __profilin=p%3Dt; request_method=GET
Connection: keep-alive
Content-Type: multipart/form-data; boundary=---------------------------9051914041544843365972754266
Content-Length: 554
-----------------------------9051914041544843365972754266
Content-Disposition: form-data; name="text"
text default
-----------------------------9051914041544843365972754266
Content-Disposition: form-data; name="file1"; filename="a.txt"
Content-Type: text/plain
Content of a.txt.
-----------------------------9051914041544843365972754266
Content-Disposition: form-data; name="file2"; filename="a.html"
Content-Type: text/html
<!DOCTYPE html><title>Content of a.html.</title>
-----------------------------9051914041544843365972754266--
这是一个发送三个不同集合的示例 - 第一个是binary data，第二个是plain text，第三个是html，它们是由边界分隔的。
现在如何工作Spring's RestTemplate？
当您将请求标头设置为multipart/form-data时，resttemplate将从已注册的邮件转换器中选择适当的HttpMessageConverter，multipart/form-data FormHttpMessageConverter将FormHttpMessageConverter查看文档{{3} }。
但是partConverters的属性为FormHttpMessageConverter，它们是为public FormHttpMessageConverter() {
this.supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
this.supportedMediaTypes.add(MediaType.MULTIPART_FORM_DATA);
this.partConverters.add(new ByteArrayHttpMessageConverter());
StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter();
stringHttpMessageConverter.setWriteAcceptCharset(false);
this.partConverters.add(stringHttpMessageConverter);
this.partConverters.add(new ResourceHttpMessageConverter());
}
注册的转换器，默认情况下是（字符串，字节数组和资源）。这是构造函数的源代码;）
FormHttpMessageConverter简单地说，Post无法找到正确的消息转换器来编写对象Post。如果您希望将MappingJackson2HttpMessageConverter写为JSON，则应将partConverters添加到@Produces
public RestTemplate getRestTemplate() {
RestTemplate template = new RestTemplate();
template.getMessageConverters().add(0,createFormHttpConverter());
return template;
}
private static HttpMessageConverter<?> createFormHttpConverter(){
FormHttpMessageConverter formHttpMessageConverter = new FormHttpMessageConverter();
formHttpMessageConverter.setPartConverters(getPartConverters());
return formHttpMessageConverter;
}
private static List<HttpMessageConverter<?>> getPartConverters(){
RestTemplate template = new RestTemplate();
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
List<HttpMessageConverter<?>> messageConverters = template.getMessageConverters();
messageConverters.add(0,converter);
return messageConverters;
}
。
$inputJSON = file_get_contents('php://input');
$input = json_decode($inputJSON, true);
.....
//Extracting the leadgenid and passing it to fetchlead
function fetchLead($leadid) {
try {
$form = new Lead($leadid);
return $form->read()->{LeadFields::FIELD_DATA}; //array
}
catch (Exception $e) {
error_log($e->getMessage());
}
}
答案 3 :(得分：0)
您需要告诉Spring如何将请求参数映射到您的对象。您可以通过实现Alexander建议的自定义HttpMessageConterter来实现此目的，但我有一个更简单的方法：使用命令对象（有时称为表单支持对象）：
public class PostWithPicCommand() {
public PostWithPic() {}; //Default constructor is required
//name the variables like the request parameters!
private Post post;
private MultipartFile image;
Getter and Setter!
}
@RequestMapping(value = "/uploadpostpic", method = RequestMethod.POST)
public Post uploadPostWithPic(PostWithPicCommand postWithPicCommand
/*no @Param attribte for postWithPicCommand*/) {
....
}
您需要配置/注册弹簧Multipart Resolver，并需要将请求作为多部分请求发送。
答案 4 :(得分：0)
我用这个做了类似的东西：
HttpHeaders headers = new HttpHeaders();
headers.add("Accept","application/json");
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
MultiValueMap<String, Object> map = new LinkedMultiValueMap<String, Object>();
map.add("image", new FileSystemResource(file));
map.add("post", post);
HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<MultiValueMap<String, Object>>(map, headers);
RestTemplate restTemplate = RestClientConfig.getRestTemplate(context, true);
restTemplate.getMessageConverters().add(new FormHttpMessageConverter());
ResponseEntity<Post> response = restTemplate.postForObject(url, requestEntity, Post.class);