From 7602a36fae19e2f33847e1d4a361a2e035dc5b8b Mon Sep 17 00:00:00 2001
From: anuragkumawat <anuragkumawat7@gmail.com>
Date: Sat, 30 Jul 2022 12:12:16 +0530
Subject: [PATCH]  JAVA-13614 Look into How to Read HTTP Headers in Spring REST
 Controllers article

---
 .../controller/ReadHeaderRestController.java    |  7 +++++--
 ...ReadHeaderRestControllerIntegrationTest.java | 17 ++++++++++++++++-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/spring-web-modules/spring-mvc-basics-3/src/main/java/com/baeldung/spring/headers/controller/ReadHeaderRestController.java b/spring-web-modules/spring-mvc-basics-3/src/main/java/com/baeldung/spring/headers/controller/ReadHeaderRestController.java
index 6a0f3b6a0d..ff4d0eea58 100644
--- a/spring-web-modules/spring-mvc-basics-3/src/main/java/com/baeldung/spring/headers/controller/ReadHeaderRestController.java
+++ b/spring-web-modules/spring-mvc-basics-3/src/main/java/com/baeldung/spring/headers/controller/ReadHeaderRestController.java
@@ -1,6 +1,8 @@
 package com.baeldung.spring.headers.controller;
 
 import java.net.InetSocketAddress;
+import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -24,9 +26,10 @@ public class ReadHeaderRestController {
     }
 
     @GetMapping("/greeting")
-    public ResponseEntity<String> greeting(@RequestHeader(value = "accept-language") String language) {
+    public ResponseEntity<String> greeting(@RequestHeader(value = HttpHeaders.ACCEPT_LANGUAGE) String language) {
         String greeting = "";
-        String firstLanguage = (language.length() > 1 ? language.substring(0, 2) : language);
+        List<Locale.LanguageRange> ranges = Locale.LanguageRange.parse(language);
+        String firstLanguage = ranges.get(0).getRange();
         switch (firstLanguage) {
         case "es":
             greeting = "Hola!";
diff --git a/spring-web-modules/spring-mvc-basics-3/src/test/java/com/baeldung/headers/controller/ReadHeaderRestControllerIntegrationTest.java b/spring-web-modules/spring-mvc-basics-3/src/test/java/com/baeldung/headers/controller/ReadHeaderRestControllerIntegrationTest.java
index 6f94004cc7..1641939b67 100644
--- a/spring-web-modules/spring-mvc-basics-3/src/test/java/com/baeldung/headers/controller/ReadHeaderRestControllerIntegrationTest.java
+++ b/spring-web-modules/spring-mvc-basics-3/src/test/java/com/baeldung/headers/controller/ReadHeaderRestControllerIntegrationTest.java
@@ -10,6 +10,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
 import org.springframework.test.context.junit.jupiter.SpringExtension;
 import org.springframework.test.context.junit.jupiter.web.SpringJUnitWebConfig;
 import org.springframework.test.web.servlet.MockMvc;
@@ -51,10 +52,24 @@ public class ReadHeaderRestControllerIntegrationTest {
 
     @Test
     public void whenGetRequestSentToGreeting_thenStatusOKAndGreetingReturned() throws Exception {
-        mockMvc.perform(get("/greeting").header("accept-language", "de"))
+        mockMvc.perform(get("/greeting").header(HttpHeaders.ACCEPT_LANGUAGE, "de"))
             .andExpect(status().isOk())
             .andExpect(content().string("Hallo!"));
     }
+    
+    @Test
+    public void whenPrioritizedListGetRequestSentToGreeting_thenStatusOKAndGreetingReturned() throws Exception {
+        mockMvc.perform(get("/greeting").header(HttpHeaders.ACCEPT_LANGUAGE, "fr,en,de"))
+            .andExpect(status().isOk())
+            .andExpect(content().string("Bonjour!"));
+    }
+    
+    @Test
+    public void whenWeightedListGetRequestSentToGreeting_thenStatusOKAndGreetingReturned() throws Exception {
+        mockMvc.perform(get("/greeting").header(HttpHeaders.ACCEPT_LANGUAGE, "Accept-Language: es; q=1.0, de; q=0.5"))
+            .andExpect(status().isOk())
+            .andExpect(content().string("Hola!"));
+    }
 
     @Test
     public void whenGetRequestSentToDouble_thenStatusOKAndCorrectResultReturned() throws Exception {