simplify quick-start

Author: DanielLiu1123

examples/quick-start/src/main/java/com/example/server/QuickStartApp.java

@@ -1,11 +1,21 @@
 package com.example.server;
 
+import com.example.api.UserApi;
+import com.example.api.UserApiBase;
+import java.util.List;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.web.bind.annotation.RestController;
 
 @SpringBootApplication
-public class QuickStartApp {
+@RestController
+public class QuickStartApp extends UserApiBase {
     public static void main(String[] args) {
         SpringApplication.run(QuickStartApp.class, args);
     }
+
+    @Override
+    public UserApi.UserDTO getById(String id) {
+        return new UserApi.UserDTO(id, "Freeman", List.of("Coding", "Reading"));
+    }
 }

examples/quick-start/src/main/java/com/example/server/controller/UserController.java

@@ -4,7 +4,7 @@
 import static org.assertj.core.api.Assertions.assertThatCode;
 
 import com.example.api.UserApi;
-import com.example.server.controller.UserController;
+import com.example.api.UserApiBase;
 import jakarta.validation.ConstraintViolationException;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -19,7 +19,7 @@ class QuickStartAppTest {
 
     @Test
     void testGetUser_whenArgIsValid() {
-        assertThat(userApi).isNotInstanceOf(UserController.class);
+        assertThat(userApi).isNotInstanceOf(UserApiBase.class);
 
         UserApi.UserDTO user = userApi.getById("1");
         assertThat(user.id()).isEqualTo("1");