How to send JSON from clinet and get DTO-Object on server? - angularjs

Question

At client I have:
for (var i = 0; i < $files.length; i++) {
var file = $files[i];
var data = {f_name: 'test1', s_name: 'test2'};
var fd = new FormData();
fd.append('data', angular.toJson(data));
fd.append("file", file);
$http({
method: 'POST',
url: 'EmployeeService/employee/upload',
headers: {'Content-Type': undefined},
data: fd,
transformRequest: angular.identity
})
.success(function(data, status) {
alert("success");
});
}
And on server (Spring):
#ResponseBody
#RequestMapping(value = "/upload", method = RequestMethod.POST)
public String postFile(#RequestParam(value="file", required=false) MultipartFile file,
#RequestParam(value="data") Object data) throws Exception {
System.out.println("data = " + data);
return "OK!";
}
But data is String: "{"f_name":"test1","s_name":"test2"}". A have DTO-class:
public class EmployeeDTO(){
private String f_name;
private String s_name;
//setters and getters
}
And on server I want to get:
#ResponseBody
#RequestMapping(value = "/upload", method = RequestMethod.POST)
public String postFile(#RequestParam(value="file", required=false) MultipartFile file,
#RequestParam(value="data") EmployeeDTO employeeDTO) throws Exception {
//etc.
}
How to send data from client (file and data) and on server get file and EmployeeDTO object?

Answer 1

while you can use annotation #RequestBody to get Object from json string.
for example:
#ResponseBody
#RequestMapping(value = "/test", method = RequestMethod.POST)
public String test(#RequestBody EmployeeDTO employeeDTO){
//TODO do something;
return "success";
}
or you can receive string and then use ObjectMapper to convert string to object
for example:
EmployeeDTO employeeDTO = new ObjectMapper().readValue("here is json string", EmployeeDTO.class);

Answer 2

You could register a Converter<String, EmployeeDTO> that would use Json ObjectMapper and you could write you controller method as you want (I assume you use Jackson2)
If you need that in only this method, it may be simpler to do it explicitely :
#Autowired
private MappingJackson2HttpMessageConverter jsonConverter;
#ResponseBody
#RequestMapping(value = "/upload", method = RequestMethod.POST)
public String postFile(#RequestParam(value="file", required=false) MultipartFile file,
#RequestParam(value="data") String data) throws Exception {
EmployeeDTO employeeDTO = jsonConverter.getObjectMapper().readValue(data,
EmployeeDTO.class);
return "OK!";
}
Alternatively, you could put the object directly in the FormData (angularJS side) and get it with #ModelAttribute spring side :
var fd = new FormData();
fd.append("file", file);
fd.append("f_name", 'test1');
fd.append("s_name", 'test2'};
and
#ResponseBody
#RequestMapping(value = "/upload", method = RequestMethod.POST)
public String postFile(#RequestParam(value="file", required=false) MultipartFile file,
#ModelAttribute EmployeeDTO employeeDTO) throws Exception {