custom response handling

spring-mvc-java/src/main/java/com/baeldung/annotations/CustomResponseController.java

@@ -0,0 +1,53 @@
+package com.baeldung.annotations;
+
+import java.io.IOException;
+import java.time.Year;
+
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@Controller
+@RequestMapping("/customResponse")
+public class CustomResponseController {
+
+    @GetMapping("/hello")
+    public ResponseEntity<String> hello() {
+        return new ResponseEntity<>("Hello World!", HttpStatus.OK);
+    }
+
+    @GetMapping("/age")
+    public ResponseEntity<String> age(@RequestParam("yearOfBirth") int yearOfBirth) {
+        int currentYear = Year.now().getValue();
+
+        if (currentYear < yearOfBirth) {
+            return new ResponseEntity<>("Year of birth cannot be in the future", HttpStatus.BAD_REQUEST);
+        }
+
+        int age = currentYear - yearOfBirth;
+
+        return new ResponseEntity<>("Your age is " + age, HttpStatus.OK);
+    }
+    
+    @GetMapping("/customHeader")
+    public ResponseEntity<String> customHeader() {
+        HttpHeaders headers = new HttpHeaders();
+        headers.add("Custom-Header", "foo");
+        
+        return new ResponseEntity<>("Custom header set", headers, HttpStatus.OK);
+    }
+    
+    @GetMapping("/manual")
+    public void manual(HttpServletResponse response) throws IOException {
+        response.setHeader("Custom-Header", "foo");
+        response.setStatus(200);
+        response.getWriter().println("Hello World!");
+    }
+
+}