In this post under JAX-RS Client, I will show with example how to set headers when sending the REST request.

Below is the complete code for your reference

Main Class

1  package defaultPackage;
2  
3  import jakarta.ws.rs.client.Client;
4  import jakarta.ws.rs.client.ClientBuilder;
5  import jakarta.ws.rs.client.Invocation;
6  import jakarta.ws.rs.client.WebTarget;
7  import jakarta.ws.rs.core.Response;
8  
9  public class Example8 {
10     public static void main(String[] args) {
11         Client client = ClientBuilder.newClient();
12         WebTarget webTarget = client.target("https://jsonplaceholder.typicode.com/users/2");
13         Invocation.Builder builder = webTarget.request();
14         builder = builder.header("Content-Type", "application/json");
15         Invocation invocation = builder.buildGet();
16         Response response = invocation.invoke();
17         if(response.getStatus() == 200) {
18             System.out.println("Successful");
19             String result = response.readEntity(String.class);
20             System.out.println(result);
21         } else {
22             System.out.println("Failed");
23         }
24         client.close();
25     }
26 }

In the above code, at line 14, we are setting header “Content-Type” to “application/json” by calling “header” method on “Invocation.Builder” instance.

In this way we can set headers before sending REST requests to the server.