diff --git a/src/main/java/com/vibevault/config/SecurityConfig.java b/src/main/java/com/vibevault/config/SecurityConfig.java
index f179cf6..765009f 100644
--- a/src/main/java/com/vibevault/config/SecurityConfig.java
+++ b/src/main/java/com/vibevault/config/SecurityConfig.java
@@ -39,13 +39,31 @@ public class SecurityConfig {
 
     @Bean
     public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
-        // TODO: 配置安全规则
-        // 提示：
-        // - 使用 http.authorizeHttpRequests() 配置路径权限
-        // - 使用 http.csrf(csrf -> csrf.disable()) 禁用 CSRF
-        // - 使用 http.sessionManagement() 配置无状态会话
-        // - 使用 http.exceptionHandling() 配置 401 响应
-        // - 使用 http.addFilterBefore() 添加 JWT 过滤器
+        http
+                // 配置路径权限
+                .authorizeHttpRequests(authorizeRequests -> authorizeRequests
+                        // 公开接口无需认证
+                        .requestMatchers("/api/auth/**").permitAll()
+                        .requestMatchers(HttpMethod.GET, "/api/playlists").permitAll()
+                        .requestMatchers(HttpMethod.GET, "/api/playlists/{id}").permitAll()
+                        // 其他接口需要认证
+                        .anyRequest().authenticated()
+                )
+                // 禁用 CSRF
+                .csrf(csrf -> csrf.disable())
+                // 配置无状态会话
+                .sessionManagement(sessionManagement -> sessionManagement
+                        .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
+                )
+                // 配置 401 响应
+                .exceptionHandling(exceptionHandling -> exceptionHandling
+                        .authenticationEntryPoint((request, response, authException) -> {
+                            response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
+                            response.getWriter().write("Unauthorized: Missing or invalid token");
+                        })
+                )
+                // 添加 JWT 过滤器
+                .addFilterBefore(jwtAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);
         
         return http.build();
     }
diff --git a/src/main/java/com/vibevault/controller/AuthController.java b/src/main/java/com/vibevault/controller/AuthController.java
index 88066a1..1c6b9cd 100644
--- a/src/main/java/com/vibevault/controller/AuthController.java
+++ b/src/main/java/com/vibevault/controller/AuthController.java
@@ -36,9 +36,43 @@ public class AuthController {
         this.jwtService = jwtService;
     }
 
-    // TODO: 实现 POST /api/auth/register (状态码 201)
+    // POST /api/auth/register - 用户注册
+    @PostMapping("/register")
+    @ResponseStatus(HttpStatus.CREATED)
+    public RegisterResponse register(@RequestBody RegisterRequest request) {
+        // 检查用户名是否已存在
+        if (userRepository.existsByUsername(request.username())) {
+            throw new ResponseStatusException(HttpStatus.CONFLICT, "Username already exists");
+        }
 
-    // TODO: 实现 POST /api/auth/login
+        // 创建新用户，加密密码
+        User user = new User();
+        user.setUsername(request.username());
+        user.setPassword(passwordEncoder.encode(request.password()));
+
+        // 保存用户到数据库
+        userRepository.save(user);
+
+        return new RegisterResponse("User registered successfully", user.getUsername());
+    }
+
+    // POST /api/auth/login - 用户登录
+    @PostMapping("/login")
+    public LoginResponse login(@RequestBody LoginRequest request) {
+        // 检查用户名是否存在
+        User user = userRepository.findByUsername(request.username())
+                .orElseThrow(() -> new ResponseStatusException(HttpStatus.UNAUTHORIZED, "Invalid username or password"));
+
+        // 验证密码
+        if (!passwordEncoder.matches(request.password(), user.getPassword())) {
+            throw new ResponseStatusException(HttpStatus.UNAUTHORIZED, "Invalid username or password");
+        }
+
+        // 生成JWT token
+        String token = jwtService.generateToken(user.getUsername());
+
+        return new LoginResponse(token, user.getUsername());
+    }
 }
 
 /**
diff --git a/src/main/java/com/vibevault/controller/PlaylistController.java b/src/main/java/com/vibevault/controller/PlaylistController.java
index 20a5e9c..af63303 100644
--- a/src/main/java/com/vibevault/controller/PlaylistController.java
+++ b/src/main/java/com/vibevault/controller/PlaylistController.java
@@ -39,19 +39,61 @@ public class PlaylistController {
         this.playlistService = playlistService;
     }
 
-    // TODO: 实现 GET /api/playlists
+    // GET /api/playlists - 获取所有歌单（公开）
+    @GetMapping
+    public List<PlaylistDTO> getAllPlaylists() {
+        return playlistService.getAllPlaylists();
+    }
 
-    // TODO: 实现 GET /api/playlists/{id}
+    // GET /api/playlists/{id} - 获取指定歌单（公开）
+    @GetMapping("/{id}")
+    public PlaylistDTO getPlaylistById(@PathVariable Long id) {
+        return playlistService.getPlaylistById(id);
+    }
 
-    // TODO: 实现 POST /api/playlists (状态码 201)
+    // POST /api/playlists - 创建歌单（需认证）
+    @PostMapping
+    @ResponseStatus(HttpStatus.CREATED)
+    public PlaylistDTO createPlaylist(@RequestBody PlaylistCreateDTO playlistCreateDTO, Authentication authentication) {
+        String username = authentication.getName();
+        return playlistService.createPlaylist(playlistCreateDTO.getName(), username);
+    }
 
-    // TODO: 实现 POST /api/playlists/{id}/songs (状态码 201)
+    // POST /api/playlists/{id}/songs - 添加歌曲（需认证）
+    @PostMapping("/{id}/songs")
+    @ResponseStatus(HttpStatus.CREATED)
+    public PlaylistDTO addSongToPlaylist(@PathVariable Long id, @RequestBody SongCreateDTO songCreateDTO, Authentication authentication) {
+        String username = authentication.getName();
+        return playlistService.addSongToPlaylist(id, songCreateDTO, username);
+    }
 
-    // TODO: 实现 DELETE /api/playlists/{playlistId}/songs/{songId} (状态码 204)
+    // DELETE /api/playlists/{playlistId}/songs/{songId} - 移除歌曲（需认证）
+    @DeleteMapping("/{playlistId}/songs/{songId}")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    public void removeSongFromPlaylist(@PathVariable Long playlistId, @PathVariable Long songId, Authentication authentication) {
+        String username = authentication.getName();
+        playlistService.removeSongFromPlaylist(playlistId, songId, username);
+    }
 
-    // TODO: 实现 DELETE /api/playlists/{id} (状态码 204)
+    // DELETE /api/playlists/{id} - 删除歌单（需认证）
+    @DeleteMapping("/{id}")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    public void deletePlaylist(@PathVariable Long id, Authentication authentication) {
+        String username = authentication.getName();
+        playlistService.deletePlaylist(id, username);
+    }
 
-    // TODO [Advanced]: 实现 GET /api/playlists/search?keyword=xxx
+    // [Advanced] GET /api/playlists/search?keyword=xxx - 搜索歌单
+    @GetMapping("/search")
+    public List<PlaylistDTO> searchPlaylists(@RequestParam String keyword) {
+        return playlistService.searchPlaylists(keyword);
+    }
 
-    // TODO [Advanced]: 实现 POST /api/playlists/{id}/copy?newName=xxx (状态码 201)
+    // [Advanced] POST /api/playlists/{id}/copy?newName=xxx - 复制歌单
+    @PostMapping("/{id}/copy")
+    @ResponseStatus(HttpStatus.CREATED)
+    public PlaylistDTO copyPlaylist(@PathVariable Long id, @RequestParam String newName, Authentication authentication) {
+        String username = authentication.getName();
+        return playlistService.copyPlaylist(id, newName, username);
+    }
 }
diff --git a/src/main/java/com/vibevault/exception/UnauthorizedAccessException.java b/src/main/java/com/vibevault/exception/UnauthorizedAccessException.java
new file mode 100644
index 0000000..be2905f
--- /dev/null
+++ b/src/main/java/com/vibevault/exception/UnauthorizedAccessException.java
@@ -0,0 +1,12 @@
+package com.vibevault.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.FORBIDDEN)
+public class UnauthorizedAccessException extends RuntimeException {
+
+    public UnauthorizedAccessException(String message) {
+        super(message);
+    }
+}
diff --git a/src/main/java/com/vibevault/model/Playlist.java b/src/main/java/com/vibevault/model/Playlist.java
index 129868f..ed77191 100644
--- a/src/main/java/com/vibevault/model/Playlist.java
+++ b/src/main/java/com/vibevault/model/Playlist.java
@@ -16,14 +16,22 @@ import java.util.List;
  * - 一个歌单包含多首歌曲（一对多关系）
  * - 删除歌单时应级联删除其中的歌曲
  */
+@Entity
+@Table(name = "playlists")
 public class Playlist {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
+    @Column(nullable = false)
     private String name;
 
+    @ManyToOne
+    @JoinColumn(name = "owner_id", nullable = false)
     private User owner;
 
+    @OneToMany(mappedBy = "playlist", cascade = CascadeType.ALL, orphanRemoval = true)
     private List<Song> songs = new ArrayList<>();
 
     protected Playlist() {
@@ -59,7 +67,8 @@ public class Playlist {
      * 提示：需要维护双向关系
      */
     public void addSong(Song song) {
-        // TODO: 实现添加歌曲逻辑
+        songs.add(song);
+        song.setPlaylist(this);
     }
 
     /**
@@ -67,6 +76,7 @@ public class Playlist {
      * 提示：需要维护双向关系
      */
     public void removeSong(Song song) {
-        // TODO: 实现移除歌曲逻辑
+        songs.remove(song);
+        song.setPlaylist(null);
     }
 }
diff --git a/src/main/java/com/vibevault/model/Song.java b/src/main/java/com/vibevault/model/Song.java
index 953c654..956528a 100644
--- a/src/main/java/com/vibevault/model/Song.java
+++ b/src/main/java/com/vibevault/model/Song.java
@@ -10,16 +10,25 @@ import jakarta.persistence.*;
  * - id 作为自增主键
  * - 每首歌曲属于一个歌单（多对一关系）
  */
+@Entity
+@Table(name = "songs")
 public class Song {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
+    @Column(nullable = false)
     private String title;
 
+    @Column(nullable = false)
     private String artist;
 
+    @Column(nullable = false)
     private int durationInSeconds;
 
+    @ManyToOne
+    @JoinColumn(name = "playlist_id")
     private Playlist playlist;
 
     public Song() {
diff --git a/src/main/java/com/vibevault/model/User.java b/src/main/java/com/vibevault/model/User.java
index b4caa63..3b6072b 100644
--- a/src/main/java/com/vibevault/model/User.java
+++ b/src/main/java/com/vibevault/model/User.java
@@ -12,15 +12,22 @@ import jakarta.persistence.*;
  * - password 不能为空
  * - [Challenge] 支持用户角色（如 ROLE_USER, ROLE_ADMIN）
  */
+@Entity
+@Table(name = "users")
 public class User {
 
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
+    @Column(unique = true, nullable = false)
     private String username;
 
+    @Column(nullable = false)
     private String password;
 
     // [Challenge] 用户角色，默认为 ROLE_USER
+    @Column(nullable = false)
     private String role = "ROLE_USER";
 
     protected User() {
@@ -49,6 +56,14 @@ public class User {
         return password;
     }
 
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
     public String getRole() {
         return role;
     }
diff --git a/src/main/java/com/vibevault/repository/PlaylistRepository.java b/src/main/java/com/vibevault/repository/PlaylistRepository.java
index c57a35a..8268d7e 100644
--- a/src/main/java/com/vibevault/repository/PlaylistRepository.java
+++ b/src/main/java/com/vibevault/repository/PlaylistRepository.java
@@ -18,5 +18,9 @@ import java.util.List;
  */
 @Repository
 public interface PlaylistRepository extends JpaRepository<Playlist, Long> {
-    // TODO [Advanced]: 添加高级查询方法
+    // 按所有者查询歌单
+    List<Playlist> findByOwner(User owner);
+    
+    // [Advanced]: 按名称模糊搜索歌单
+    List<Playlist> findByNameContainingIgnoreCase(String keyword);
 }
diff --git a/src/main/java/com/vibevault/repository/UserRepository.java b/src/main/java/com/vibevault/repository/UserRepository.java
index 0b76601..7a47bc5 100644
--- a/src/main/java/com/vibevault/repository/UserRepository.java
+++ b/src/main/java/com/vibevault/repository/UserRepository.java
@@ -15,5 +15,9 @@ import java.util.Optional;
  */
 @Repository
 public interface UserRepository extends JpaRepository<User, Long> {
-    // TODO: 添加必要的查询方法
+    // 根据用户名查找用户
+    Optional<User> findByUsername(String username);
+    
+    // 检查用户名是否已存在
+    boolean existsByUsername(String username);
 }
diff --git a/src/main/java/com/vibevault/security/JwtAuthenticationFilter.java b/src/main/java/com/vibevault/security/JwtAuthenticationFilter.java
index be2a0bb..1adb9a8 100644
--- a/src/main/java/com/vibevault/security/JwtAuthenticationFilter.java
+++ b/src/main/java/com/vibevault/security/JwtAuthenticationFilter.java
@@ -45,17 +45,41 @@ public class JwtAuthenticationFilter extends OncePerRequestFilter {
             @NonNull FilterChain filterChain
     ) throws ServletException, IOException {
         
-        // TODO: 实现 JWT 认证逻辑
         // 1. 从请求头获取 Authorization
+        final String authHeader = request.getHeader("Authorization");
+        final String jwt;
+        final String username;
+        
         // 2. 检查是否以 "Bearer " 开头
+        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
+            filterChain.doFilter(request, response);
+            return;
+        }
+        
         // 3. 提取 token 并验证
+        jwt = authHeader.substring(7);
+        username = jwtService.extractUsername(jwt);
+        
         // 4. 如果有效，创建 Authentication 并设置到 SecurityContextHolder
-        // 
-        // 提示：
-        // - 使用 request.getHeader("Authorization") 获取头
-        // - 使用 jwtService.extractUsername() 和 jwtService.isTokenValid()
-        // - 使用 UsernamePasswordAuthenticationToken 创建认证对象
-        // - 使用 SecurityContextHolder.getContext().setAuthentication() 设置
+        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
+            User user = userRepository.findByUsername(username)
+                    .orElse(null);
+            
+            if (user != null && jwtService.isTokenValid(jwt, user)) {
+                // 设置用户角色（当前只有默认角色）
+                List<SimpleGrantedAuthority> authorities = Collections.singletonList(
+                        new SimpleGrantedAuthority("ROLE_USER")
+                );
+                
+                UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(
+                        user, null, authorities
+                );
+                authToken.setDetails(
+                        new WebAuthenticationDetailsSource().buildDetails(request)
+                );
+                SecurityContextHolder.getContext().setAuthentication(authToken);
+            }
+        }
         
         filterChain.doFilter(request, response);
     }
diff --git a/src/main/java/com/vibevault/security/JwtService.java b/src/main/java/com/vibevault/security/JwtService.java
index f94e85a..a87fef7 100644
--- a/src/main/java/com/vibevault/security/JwtService.java
+++ b/src/main/java/com/vibevault/security/JwtService.java
@@ -30,26 +30,54 @@ public class JwtService {
      * 为用户生成 JWT token
      */
     public String generateToken(String username) {
-        // TODO: 实现 token 生成
-        // 提示：使用 Jwts.builder()
-        throw new UnsupportedOperationException("待实现");
+        Date now = new Date();
+        Date expirationDate = new Date(now.getTime() + expiration);
+
+        return Jwts.builder()
+                .subject(username)
+                .issuedAt(now)
+                .expiration(expirationDate)
+                .signWith(getSigningKey())
+                .compact();
     }
 
     /**
      * 从 token 中提取用户名
      */
     public String extractUsername(String token) {
-        // TODO: 实现用户名提取
-        // 提示：使用 Jwts.parser()
-        throw new UnsupportedOperationException("待实现");
+        return Jwts.parser()
+                .verifyWith(getSigningKey())
+                .build()
+                .parseSignedClaims(token)
+                .getPayload()
+                .getSubject();
     }
 
     /**
      * 验证 token 是否有效
      */
     public boolean isTokenValid(String token, String username) {
-        // TODO: 实现 token 验证
-        throw new UnsupportedOperationException("待实现");
+        try {
+            String extractedUsername = extractUsername(token);
+            Date expirationDate = Jwts.parser()
+                    .verifyWith(getSigningKey())
+                    .build()
+                    .parseSignedClaims(token)
+                    .getPayload()
+                    .getExpiration();
+            Date now = new Date();
+
+            return username.equals(extractedUsername) && expirationDate.after(now);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+    
+    /**
+     * 验证 token 是否对特定用户有效
+     */
+    public boolean isTokenValid(String token, com.vibevault.model.User user) {
+        return isTokenValid(token, user.getUsername());
     }
 
     /**
diff --git a/src/main/java/com/vibevault/service/impl/PlaylistServiceImpl.java b/src/main/java/com/vibevault/service/impl/PlaylistServiceImpl.java
new file mode 100644
index 0000000..6ef5b47
--- /dev/null
+++ b/src/main/java/com/vibevault/service/impl/PlaylistServiceImpl.java
@@ -0,0 +1,153 @@
+package com.vibevault.service.impl;
+
+import com.vibevault.dto.PlaylistDTO;
+import com.vibevault.dto.SongCreateDTO;
+import com.vibevault.exception.ResourceNotFoundException;
+import com.vibevault.exception.UnauthorizedAccessException;
+import com.vibevault.model.Playlist;
+import com.vibevault.model.Song;
+import com.vibevault.model.User;
+import com.vibevault.repository.PlaylistRepository;
+import com.vibevault.repository.UserRepository;
+import com.vibevault.service.PlaylistService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Service
+public class PlaylistServiceImpl implements PlaylistService {
+
+    private final PlaylistRepository playlistRepository;
+    private final UserRepository userRepository;
+
+    @Autowired
+    public PlaylistServiceImpl(PlaylistRepository playlistRepository, UserRepository userRepository) {
+        this.playlistRepository = playlistRepository;
+        this.userRepository = userRepository;
+    }
+
+    @Override
+    public List<PlaylistDTO> getAllPlaylists() {
+        return playlistRepository.findAll().stream()
+                .map(this::convertToDTO)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public PlaylistDTO getPlaylistById(Long id) {
+        Playlist playlist = playlistRepository.findById(id)
+                .orElseThrow(() -> new ResourceNotFoundException("Playlist not found with id: " + id));
+        return convertToDTO(playlist);
+    }
+
+    @Override
+    @Transactional
+    public PlaylistDTO createPlaylist(String name, String ownerUsername) {
+        User owner = userRepository.findByUsername(ownerUsername)
+                .orElseThrow(() -> new ResourceNotFoundException("User not found with username: " + ownerUsername));
+
+        Playlist playlist = new Playlist();
+        playlist.setName(name);
+        playlist.setOwner(owner);
+
+        Playlist savedPlaylist = playlistRepository.save(playlist);
+        return convertToDTO(savedPlaylist);
+    }
+
+    @Override
+    @Transactional
+    public PlaylistDTO addSongToPlaylist(Long playlistId, SongCreateDTO songDTO, String username) {
+        Playlist playlist = getPlaylistWithOwnershipCheck(playlistId, username);
+
+        Song song = new Song();
+        song.setTitle(songDTO.getTitle());
+        song.setArtist(songDTO.getArtist());
+        song.setDurationInSeconds(songDTO.getDurationInSeconds());
+
+        playlist.addSong(song);
+        Playlist savedPlaylist = playlistRepository.save(playlist);
+        return convertToDTO(savedPlaylist);
+    }
+
+    @Override
+    @Transactional
+    public void removeSongFromPlaylist(Long playlistId, Long songId, String username) {
+        Playlist playlist = getPlaylistWithOwnershipCheck(playlistId, username);
+
+        Song song = playlist.getSongs().stream()
+                .filter(s -> s.getId().equals(songId))
+                .findFirst()
+                .orElseThrow(() -> new ResourceNotFoundException("Song not found in playlist with id: " + songId));
+
+        playlist.removeSong(song);
+        playlistRepository.save(playlist);
+    }
+
+    @Override
+    @Transactional
+    public void deletePlaylist(Long playlistId, String username) {
+        Playlist playlist = getPlaylistWithOwnershipCheck(playlistId, username);
+        playlistRepository.delete(playlist);
+    }
+
+    // ========== Advanced 方法（选做）==========
+
+    @Override
+    public List<PlaylistDTO> searchPlaylists(String keyword) {
+        return playlistRepository.findByNameContainingIgnoreCase(keyword).stream()
+                .map(this::convertToDTO)
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    @Transactional
+    public PlaylistDTO copyPlaylist(Long playlistId, String newName, String username) {
+        Playlist originalPlaylist = playlistRepository.findById(playlistId)
+                .orElseThrow(() -> new ResourceNotFoundException("Playlist not found with id: " + playlistId));
+
+        User newOwner = userRepository.findByUsername(username)
+                .orElseThrow(() -> new ResourceNotFoundException("User not found with username: " + username));
+
+        Playlist copiedPlaylist = new Playlist();
+        copiedPlaylist.setName(newName);
+        copiedPlaylist.setOwner(newOwner);
+
+        // 复制歌曲
+        for (Song originalSong : originalPlaylist.getSongs()) {
+            Song copiedSong = new Song();
+            copiedSong.setTitle(originalSong.getTitle());
+            copiedSong.setArtist(originalSong.getArtist());
+            copiedSong.setDurationInSeconds(originalSong.getDurationInSeconds());
+            copiedPlaylist.addSong(copiedSong);
+        }
+
+        Playlist savedPlaylist = playlistRepository.save(copiedPlaylist);
+        return convertToDTO(savedPlaylist);
+    }
+
+    // 辅助方法：检查歌单所有权
+    private Playlist getPlaylistWithOwnershipCheck(Long playlistId, String username) {
+        Playlist playlist = playlistRepository.findById(playlistId)
+                .orElseThrow(() -> new ResourceNotFoundException("Playlist not found with id: " + playlistId));
+
+        // 检查是否为歌单所有者
+        if (!playlist.getOwner().getUsername().equals(username)) {
+            throw new UnauthorizedAccessException("You don't have permission to modify this playlist");
+        }
+
+        return playlist;
+    }
+
+    // 辅助方法：将 Playlist 转换为 PlaylistDTO
+    private PlaylistDTO convertToDTO(Playlist playlist) {
+        PlaylistDTO dto = new PlaylistDTO();
+        dto.setId(playlist.getId());
+        dto.setName(playlist.getName());
+        dto.setOwnerUsername(playlist.getOwner().getUsername());
+        dto.setSongCount(playlist.getSongs().size());
+        return dto;
+    }
+}