Implement authenticated function

src/main/java/com/example/springdemo/controller/AuthController.java

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+package com.example.springdemo.controller;
+
+import com.example.springdemo.security.dto.JwtAuthResponse;
+import com.example.springdemo.security.dto.LoginDto;
+import com.example.springdemo.service.AuthService;
+import jakarta.annotation.Resource;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/auth")
+public class AuthController {
+    @Resource
+    private AuthService authService;
+
+    // Login REST API
+    @PostMapping("/login")
+    public ResponseEntity<JwtAuthResponse> authenticate(@RequestBody LoginDto loginDto) {
+        String token = authService.login(loginDto);
+
+        JwtAuthResponse jwtAuthResponse = new JwtAuthResponse(token);
+
+        return ResponseEntity.ok(jwtAuthResponse);
+    }
+}

src/main/java/com/example/springdemo/service/AuthService.java

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+package com.example.springdemo.service;
+
+import com.example.springdemo.security.dto.LoginDto;
+
+public interface AuthService {
+    String login(LoginDto loginDto);
+}

src/main/java/com/example/springdemo/serviceImpl/AuthServiceImpl.java

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+package com.example.springdemo.serviceImpl;
+
+import com.example.springdemo.security.dto.LoginDto;
+import com.example.springdemo.security.utils.JwtTokenProvider;
+import com.example.springdemo.service.AuthService;
+import jakarta.annotation.Resource;
+import org.jetbrains.annotations.NotNull;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.stereotype.Service;
+
+@Service
+public class AuthServiceImpl implements AuthService {
+    @Resource
+    private AuthenticationManager authenticationManager;
+    @Resource
+    private JwtTokenProvider jwtTokenProvider;
+
+    @Override
+    public String login(@NotNull LoginDto loginDto) {
+        Authentication authentication = authenticationManager.authenticate(
+                new UsernamePasswordAuthenticationToken(loginDto.getUsername(), loginDto.getPassword())
+        );
+        SecurityContextHolder.getContext().setAuthentication(authentication);
+        return jwtTokenProvider.generateToken(authentication);
+    }
+}