Hack to upload a file from Java backend to a remote server over HTTP using Rest API.

Question

My file resides on some location on my machine say C://users//abc.txt and i want to write a java program to transfer this file using REST API over HTTP. I used MockHttpServelet Request to create the request, but somehow i am unable to transfer the file

Answer 1

Use HttpClient:

String url = "http://localhost:8080/upload"; // Replace with your target 'REST API' url
String filePath = "C://users//abc.txt";

CloseableHttpClient httpClient = HttpClients.createDefault();
try {
    HttpPost httpPost = new HttpPost(url);
    FileEntity entity = new FileEntity(new File(filePath), ContentType.TEXT_PLAIN);
    httpPost.setEntity(entity);

    HttpResponse httpResponse = httpClient.execute(httpPost);
    System.out.println(httpResponse.getStatusLine().getStatusCode()); // Check HTTP code
} finally {
    httpClient.close();
}

With Authentication:

String url = "http://localhost:8080/upload"; // Replace with your target 'REST API' url
String filePath = "C://users//abc.txt";
String username = "username"; // Replace with your username
String password = "password"; // Replace with your password

RequestConfig requestConfig =
  RequestConfig.custom().
    setAuthenticationEnable(true).
    build();

CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
credentialsProvider.setCredentials(
  AuthScope.ANY,
  new UsernamePasswordCredential(username, password));

CloseableHttpClient httpClient =
  HttpClients.custom().
    setDefaultRequestConfig(requestConfig).
    setDefaultCredentialsProvider(credentialsProvider).
    build();
try {
    HttpPost httpPost = new HttpPost(url);
    FileEntity entity = new FileEntity(new File(filePath), ContentType.TEXT_PLAIN);
    httpPost.setEntity(entity);

    HttpResponse httpResponse = httpClient.execute(httpPost);
    System.out.println(httpResponse.getStatusLine().getStatusCode()); // Check HTTP code
} finally {
    httpClient.close();
}