How can I get the json file from ResponseEntity? - json

Question

I have my web service consuming another web service. in my web service I modify some fields of the json. then in postman it is consumed ok.
Now I need to convert the ResponseEntity to a .json file to save it to a folder on my computer, but the attempt has failed.
Any ideas?
my controller current:
#Controller
public class SiviccController {
private final Logger log = LoggerFactory.getLogger(SiviccController.class);
private String url = "http://localhost:9090/url_1";
#GetMapping("/url_2")
#ResponseBody
public Body sivicc() {
RestTemplate restTemplate = new RestTemplate(Factory.timeoutHttp());
try {
return restTemplate.getForObject(url, Body.class);
} catch (Exception e) {
Body body = new Body();
body.setIserror(true);
log.info(e.getMessage());
return body;
}
}
}
Matheus Cirillo works perfectly with the following code:
#Controller
public class SiviccController {
private final Logger log = LoggerFactory.getLogger(SiviccController.class);
private String url = "http://localhost:9090/url_1";
#GetMapping("/url_2")
#ResponseBody
public Body sivicc() {
RestTemplate restTemplate = new RestTemplate(Factory.timeoutHttp());
try {
String response = restTemplate.getForObject(url, String.class);
BufferedWriter writer = new BufferedWriter(new FileWriter("my-file.json", true));
writer.append(response);
writer.close();
return restTemplate.getForObject(url, Body.class);
} catch (Exception e) {
Body body = new Body();
body.setIserror(true);
log.info(e.getMessage());
return body;
}
}
}
However, the web service that you were consuming before now generates a token. That's why I change getForObject to exchange and I consume it well, but I apply the same logic to save the json in a folder on my computer, but it generates a failure in two lines:
#Controller
public class SiviccController {
private final Logger log = LoggerFactory.getLogger(SiviccController.class);
private String url = "http://localhost:9090/url_1";
#GetMapping("/url_2")
#ResponseBody
public Body sivicc() {
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
headers.set("Authorization", "bearer 8P7oM_ZDhB3TYolVkB1MLtM734DrrUSMVEFuiy3u");
HttpEntity request = new HttpEntity(headers);
headers.add("User-Agent", "Spring's RestTemplate" );
ResponseEntity<String> response = restTemplate.exchange(
url,
HttpMethod.GET,
request,
//Body.class,
String.class,
1
);
try {
BufferedWriter writer = new BufferedWriter(new FileWriter("my-file.json", true));
writer.append(response);//Error: The method append(CharSequence) in the type Writer is not applicable for the arguments (ResponseEntity<String>)
writer.close();
return response.getBody();//Error: Type mismatch: cannot convert from String to Body
} catch (Exception e) {
Body body = new Body();
body.setIserror(true);
log.info(e.getMessage());
return body;
}
}
}

Answer 1

Change the Response type from getForObject to String.class, then, use the BufferedWriter to write the file.
RestTemplate rest = new RestTemplate();
String response = rest.getForObject("http://example.com/", String.class);
BufferedWriter writer = new BufferedWriter(new FileWriter("my-file.json", true));
writer.append(response);
writer.close();
Edit
The RestTemplate#exchange returns a ResponseEntity<T>, not a String.
In your case, it will return a ResponseEntity<String>.
That's why you're unable to write the object. To do so, you need to get the body from the ResponseEntity object. Use the method ResponseEntity#getBody
Something like this:
ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.GET, request, String.class, 1);
BufferedWriter writer = new BufferedWriter(new FileWriter("my-file.json", true));
// here you are getting the String with the response.getBody() method,
// so buffered writer can write the file
writer.append(response.getBody());
writer.close();

Answer 2

Resolved:
add to pom.xml:
<dependencies>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.8</version>
</dependency>
</dependencies>
Use the Jackson API ObjectMapper class to convert Java Object to a JSON string
Use the BufferedWriter to write the file. #Matheus Cirillo
ObjectMapper mapper = new ObjectMapper();
try {
json = mapper.writeValueAsString(response.getBody());
System.out.println("ResultingJSONstring = " + json);
BufferedWriter writer = new BufferedWriter(new FileWriter("my-file.json", true));
writer.append(json);
writer.close();
} catch (JsonProcessingException e) {
e.printStackTrace();
}
thanks for your help =)