add

backend/src/main/java/com/nursinghome/service/UserService.java

@@ -0,0 +1,56 @@
+package com.nursinghome.service;
+
+import com.nursinghome.common.ApiException;
+import com.nursinghome.entity.User;
+import com.nursinghome.mapper.UserMapper;
+import com.nursinghome.util.PasswordUtil;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class UserService {
+    private final UserMapper userMapper;
+
+    public UserService(UserMapper userMapper) {
+        this.userMapper = userMapper;
+    }
+
+    public User findByUsername(String username) {
+        return userMapper.findByUsername(username);
+    }
+
+    public User findById(Long id) {
+        return userMapper.findById(id);
+    }
+
+    public List<User> listByRole(String role) {
+        return userMapper.listByRole(role);
+    }
+
+    public User createUser(User user, boolean hashPassword) {
+        if (userMapper.findByUsername(user.getUsername()) != null) {
+            throw new ApiException("username already exists");
+        }
+        if (hashPassword) {
+            user.setPassword(PasswordUtil.hash(user.getPassword()));
+        }
+        if (user.getStatus() == null) {
+            user.setStatus(1);
+        }
+        userMapper.insert(user);
+        return user;
+    }
+
+    public void updateUser(User user) {
+        userMapper.update(user);
+    }
+
+    public void updateStatus(Long id, Integer status) {
+        userMapper.updateStatus(id, status);
+    }
+
+    public void updatePassword(Long id, String password) {
+        userMapper.updatePassword(id, password);
+    }
+}