BAEL-7540

spring-5-webflux-2/src/main/java/com/baeldung/webflux/exceptionhandeling/controller/UserController.java

@@ -0,0 +1,35 @@
+package com.baeldung.webflux.exceptionhandeling.controller;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.webflux.exceptionhandeling.ex.NotFoundException;
+import com.baeldung.webflux.exceptionhandeling.repository.UserRepository;
+import com.baeldung.webflux.zipwhen.model.User;
+
+import reactor.core.publisher.Mono;
+
+@RestController
+public class UserController {
+
+    private final UserRepository userRepository;
+
+    @Autowired
+    public UserController(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    @GetMapping("/user/{id}")
+    public Mono<User> getUserByIdThrowingException(@PathVariable String id) {
+        return userRepository.findById(id)
+          .switchIfEmpty(Mono.error(new NotFoundException("User not found")));
+    }
+
+    @GetMapping("/user/{id}")
+    public Mono<User> getUserByIdUsingMonoError(@PathVariable String id) {
+        return userRepository.findById(id)
+          .switchIfEmpty(Mono.error(() -> new NotFoundException("User not found")));
+    }
+}

spring-5-webflux-2/src/main/java/com/baeldung/webflux/exceptionhandeling/ex/NotFoundException.java

@@ -0,0 +1,12 @@
+package com.baeldung.webflux.exceptionhandeling.ex;
+
+public class NotFoundException extends RuntimeException {
+
+    public NotFoundException(String message) {
+        super(message);
+    }
+
+    public NotFoundException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

spring-5-webflux-2/src/main/java/com/baeldung/webflux/exceptionhandeling/model/User.java

@@ -0,0 +1,29 @@
+package com.baeldung.webflux.exceptionhandeling.model;
+
+public class User {
+    private String id;
+    private String username;
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public User(String userId, String userName) {
+        this.id=userId;
+        this.username=userName;
+
+    }
+}
+

spring-5-webflux-2/src/main/java/com/baeldung/webflux/exceptionhandeling/repository/UserRepository.java

@@ -0,0 +1,24 @@
+package com.baeldung.webflux.exceptionhandeling.repository;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.springframework.stereotype.Repository;
+
+import com.baeldung.webflux.zipwhen.model.User;
+
+import reactor.core.publisher.Mono;
+
+@Repository
+public class UserRepository {
+    private final Map<String, User> userDatabase = new ConcurrentHashMap<>();
+
+    public UserRepository() {
+        userDatabase.put("1", new User("1", "John Doe"));
+        userDatabase.put("2", new User("2", "Jane Smith"));
+    }
+
+    public Mono<User> findById(String id) {
+        return Mono.justOrEmpty(userDatabase.get(id));
+    }
+}