BAEL-5487-java-httpclient-custom-header (#12269)

Co-authored-by: tienvn4 <tienvn4@ghtk.co>

core-java-modules/core-java-httpclient/src/main/java/com/baeldung/httpclient/HttpClientHeader.java

@@ -0,0 +1,46 @@
+package com.baeldung.httpclient;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+
+public class HttpClientHeader {
+
+    public static HttpResponse<String> callWithCustomHeader(String url) throws URISyntaxException, IOException, InterruptedException {
+        HttpClient httpClient = HttpClient.newHttpClient();
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .header("X-Our-Header-1", "value1")
+            .header("X-Our-Header-1", "value2")
+            .header("X-Our-Header-2", "value2")
+            .uri(new URI(url)).build();
+
+        return httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+    }
+
+    public static HttpResponse<String> callWithCustomHeaderV2(String url) throws URISyntaxException, IOException, InterruptedException {
+        HttpClient httpClient = HttpClient.newHttpClient();
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .headers("X-Our-Header-1", "value1", "X-Our-Header-1", "value2")
+            .uri(new URI(url)).build();
+
+        return httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+    }
+
+    public static HttpResponse<String> callWithCustomHeaderV3(String url) throws URISyntaxException, IOException, InterruptedException {
+        HttpClient httpClient = HttpClient.newHttpClient();
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .setHeader("X-Our-Header-1", "value1")
+            .setHeader("X-Our-Header-1", "value2")
+            .uri(new URI(url)).build();
+
+        return httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+    }
+
+
+}