See this page for an example of a REST application: JAX-RS: Sample Application (Jersey, Spring, Tomcat)

<dependency> <groupId>javax.ws.rs</groupId> <artifactId>javax.ws.rs-api</artifactId> <version>2.1.1</version> </dependency>

• Java example:
  
  import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import java.util.List; import java.util.Map; import javax.ws.rs.HttpMethod; import javax.ws.rs.core.MediaType; public class Test { public static void main(String[] args) throws IOException { final String urlString = "http://localhost:8080/mtitek-rest-sample-1.0.0-SNAPSHOT/rest/myEntity/getMyEntity1?qpvalue1=val11&qpvalue2=val21&qpvalue3=val31"; final int connectTimeout = 1000; HttpURLConnection connection = null; try { final URL url = new URL(urlString); connection = (HttpURLConnection) url.openConnection(); connection.setConnectTimeout(connectTimeout); connection.setRequestMethod(HttpMethod.GET); connection.setRequestProperty("Accept", MediaType.APPLICATION_XML); // response code System.out.println(connection.getResponseCode()); // response headers final Map<String, List<String>> headerFields = connection.getHeaderFields(); for (Map.Entry<String, List<String>> entry : headerFields.entrySet()) { System.out.println("Header [Key: " + entry.getKey() + " - Value: " + entry.getValue() + "]"); } // response body if (connection.getInputStream() != null) { final InputStream inputStream = connection.getInputStream(); final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); try { final StringBuilder response = new StringBuilder(); String line; while ((line = bufferedReader.readLine()) != null) { response.append(line); } System.out.println(response.toString()); } finally { if (bufferedReader != null) { bufferedReader.close(); } } } } catch (Exception e) { e.printStackTrace(); } finally { if (connection != null) { connection.disconnect(); } } } }
  
• Sample JAX-RS GET resource:
  
  @GET @Path("/getMyEntity1") public Response getMyEntity1(@QueryParam(value = "qpvalue1") final String value1, @QueryParam(value = "qpvalue2") final String value2, @QueryParam(value = "qpvalue3") final String value3) { MyEntity myEntity = new MyEntity(); //... return Response.ok(myEntity).build(); }
  
• Request/Response:
  
  200 Header [Key: null - Value: [HTTP/1.1 200]] Header [Key: Content-Length - Value: [688]] Header [Key: Date - Value: [Mon, 21 Oct 2018 00:45:54 GMT]] Header [Key: Content-Type - Value: [application/xml]] <?xml version="1.0" encoding="UTF-8" standalone="yes"?><myEntity ...
  

• Java example:
  
  import java.io.BufferedReader; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.List; import java.util.Map; import javax.ws.rs.HttpMethod; import javax.ws.rs.core.MediaType; public class Test { public static void main(String[] args) throws IOException { final String urlString = "http://localhost:8080/mtitek-rest-sample-1.0.0-SNAPSHOT/rest/myEntity/postMyEntity1?qpvalue1=val11&qpvalue2=val21&qpvalue3=val31"; final int connectTimeout = 1000; HttpURLConnection connection = null; try { final URL url = new URL(urlString); connection = (HttpURLConnection) url.openConnection(); connection.setConnectTimeout(connectTimeout); connection.setRequestMethod(HttpMethod.POST); connection.setRequestProperty("Content-Type", MediaType.APPLICATION_FORM_URLENCODED); connection.setRequestProperty("Accept", MediaType.APPLICATION_XML); connection.setUseCaches(false); connection.setDoOutput(true); final OutputStream outputStream = connection.getOutputStream(); final DataOutputStream dataOutputStream = new DataOutputStream(outputStream); dataOutputStream.close(); // response code System.out.println(connection.getResponseCode()); // response headers final Map<String, List<String>> headerFields = connection.getHeaderFields(); for (Map.Entry<String, List<String>> entry : headerFields.entrySet()) { System.out.println("Header [Key: " + entry.getKey() + " - Value: " + entry.getValue() + "]"); } // response body if (connection.getInputStream() != null) { final InputStream inputStream = connection.getInputStream(); final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); try { StringBuilder response = new StringBuilder(); String line; while ((line = bufferedReader.readLine()) != null) { response.append(line); } System.out.println(response.toString()); } finally { if (bufferedReader != null) { bufferedReader.close(); } } } } catch (Exception e) { e.printStackTrace(); } finally { if (connection != null) { connection.disconnect(); } } } }
  
• Sample JAX-RS POST resource:
  
  @POST @Path("/postMyEntity1") public Response postMyEntity1(@QueryParam(value = "qpvalue1") final String value1, @QueryParam(value = "qpvalue2") final String value2, @QueryParam(value = "qpvalue3") final String value3) { MyEntity myEntity = new MyEntity(); //... return Response.ok(myEntity).build(); }
  
• Request/Response:
  
  200 Header [Key: null - Value: [HTTP/1.1 200]] Header [Key: Content-Length - Value: [996]] Header [Key: Date - Value: [Mon, 21 Oct 2018 00:48:39 GMT]] Header [Key: Content-Type - Value: [application/xml]] <?xml version="1.0" encoding="UTF-8" standalone="yes"?><myEntity ...
  

• Java example:
  
  import java.io.BufferedReader; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.List; import java.util.Map; import javax.ws.rs.HttpMethod; import javax.ws.rs.core.MediaType; public class Test { public static void main(String[] args) throws IOException { final String urlString = "http://localhost:8080/mtitek-rest-sample-1.0.0-SNAPSHOT/rest/myEntity/postMyEntity2"; final String formParameters = "qpvalue1=val11&qpvalue2=val21&qpvalue3=val31"; final int connectTimeout = 1000; HttpURLConnection connection = null; try { final URL url = new URL(urlString); connection = (HttpURLConnection) url.openConnection(); connection.setConnectTimeout(connectTimeout); connection.setRequestMethod(HttpMethod.POST); connection.setRequestProperty("Content-Type", MediaType.APPLICATION_FORM_URLENCODED); connection.setRequestProperty("Accept", MediaType.APPLICATION_XML); connection.setUseCaches(false); connection.setDoOutput(true); final OutputStream outputStream = connection.getOutputStream(); final DataOutputStream dataOutputStream = new DataOutputStream(outputStream); dataOutputStream.writeBytes(formParameters); dataOutputStream.close(); // response code System.out.println(connection.getResponseCode()); // response headers final Map<String, List<String>> headerFields = connection.getHeaderFields(); for (Map.Entry<String, List<String>> entry : headerFields.entrySet()) { System.out.println("Header [Key: " + entry.getKey() + " - Value: " + entry.getValue() + "]"); } // response body if (connection.getInputStream() != null) { final InputStream inputStream = connection.getInputStream(); final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); try { StringBuilder response = new StringBuilder(); String line; while ((line = bufferedReader.readLine()) != null) { response.append(line); } System.out.println(response.toString()); } finally { if (bufferedReader != null) { bufferedReader.close(); } } } } catch (Exception e) { e.printStackTrace(); } finally { if (connection != null) { connection.disconnect(); } } } }
  
• Sample JAX-RS POST resource:
  
  @POST @Path("/postMyEntity2") @Consumes({ MediaType.APPLICATION_FORM_URLENCODED }) public Response postMyEntity2(@FormParam(value = "qpvalue1") final String value1, @FormParam(value = "qpvalue2") final String value2, @FormParam(value = "qpvalue3") final String value3) { MyEntity myEntity = new MyEntity(); //... return Response.ok(myEntity).build(); }
  
• Request/Response:
  
  200 Header [Key: null - Value: [HTTP/1.1 200]] Header [Key: Content-Length - Value: [934]] Header [Key: Date - Value: [Mon, 21 Oct 2018 00:49:58 GMT]] Header [Key: Content-Type - Value: [application/xml]] <?xml version="1.0" encoding="UTF-8" standalone="yes"?><myEntity ...