diff --git a/src/main/java/com/guwan/backend/entity/UserRead.java b/src/main/java/com/guwan/backend/entity/UserRead.java
new file mode 100644
index 0000000..b850186
--- /dev/null
+++ b/src/main/java/com/guwan/backend/entity/UserRead.java
@@ -0,0 +1,33 @@
+package com.guwan.backend.entity;
+
+import lombok.Data;
+
+import java.time.LocalDateTime;
+
+@Data
+public class UserRead {
+    /**
+     * 用户id
+     */
+    private Long userId;
+    /**
+     * 图书id
+     */
+    private Long bookId;
+    /**
+     * 用户上次阅读节位置
+     */
+    private Integer sectionId;
+
+    private Long thisReadingTime;
+
+    /**
+     * 该书累计阅读时间
+     */
+    private Long cumulativeReadingTime;
+    /**
+     * 上次阅读时间
+     */
+    private LocalDateTime lastReadTime;
+
+}
diff --git a/src/main/java/com/guwan/backend/mybatis/query/LambdaQueryWrapperX.java b/src/main/java/com/guwan/backend/mybatis/query/LambdaQueryWrapperX.java
new file mode 100644
index 0000000..22b4f6b
--- /dev/null
+++ b/src/main/java/com/guwan/backend/mybatis/query/LambdaQueryWrapperX.java
@@ -0,0 +1,135 @@
+package com.guwan.backend.mybatis.query;
+
+import cn.hutool.core.util.ArrayUtil;
+import cn.hutool.core.util.ObjectUtil;
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.baomidou.mybatisplus.core.toolkit.support.SFunction;
+import org.apache.commons.lang3.ArrayUtils;
+import org.springframework.util.StringUtils;
+
+import java.util.Collection;
+
+/**
+ * 拓展 MyBatis Plus QueryWrapper 类，主要增加如下功能：
+ * <p>
+ * 1. 拼接条件的方法，增加 xxxIfPresent 方法，用于判断值不存在的时候，不要拼接到条件中。
+ *
+ * @param <T> 数据类型
+ */
+public class LambdaQueryWrapperX<T> extends LambdaQueryWrapper<T> {
+
+    public LambdaQueryWrapperX<T> likeIfPresent(SFunction<T, ?> column, String val) {
+        if (StringUtils.hasText(val)) {
+            return (LambdaQueryWrapperX<T>) super.like(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> inIfPresent(SFunction<T, ?> column, Collection<?> values) {
+        if (ObjectUtil.isAllNotEmpty(values) && !ArrayUtil.isEmpty(values)) {
+            return (LambdaQueryWrapperX<T>) super.in(column, values);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> inIfPresent(SFunction<T, ?> column, Object... values) {
+        if (ObjectUtil.isAllNotEmpty(values) && !ArrayUtil.isEmpty(values)) {
+            return (LambdaQueryWrapperX<T>) super.in(column, values);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> eqIfPresent(SFunction<T, ?> column, Object val) {
+        if (ObjectUtil.isNotEmpty(val)) {
+            return (LambdaQueryWrapperX<T>) super.eq(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> neIfPresent(SFunction<T, ?> column, Object val) {
+        if (ObjectUtil.isNotEmpty(val)) {
+            return (LambdaQueryWrapperX<T>) super.ne(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> gtIfPresent(SFunction<T, ?> column, Object val) {
+        if (val != null) {
+            return (LambdaQueryWrapperX<T>) super.gt(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> geIfPresent(SFunction<T, ?> column, Object val) {
+        if (val != null) {
+            return (LambdaQueryWrapperX<T>) super.ge(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> ltIfPresent(SFunction<T, ?> column, Object val) {
+        if (val != null) {
+            return (LambdaQueryWrapperX<T>) super.lt(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> leIfPresent(SFunction<T, ?> column, Object val) {
+        if (val != null) {
+            return (LambdaQueryWrapperX<T>) super.le(column, val);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> betweenIfPresent(SFunction<T, ?> column, Object val1, Object val2) {
+        if (val1 != null && val2 != null) {
+            return (LambdaQueryWrapperX<T>) super.between(column, val1, val2);
+        }
+        if (val1 != null) {
+            return (LambdaQueryWrapperX<T>) ge(column, val1);
+        }
+        if (val2 != null) {
+            return (LambdaQueryWrapperX<T>) le(column, val2);
+        }
+        return this;
+    }
+
+    public LambdaQueryWrapperX<T> betweenIfPresent(SFunction<T, ?> column, Object[] values) {
+        Object val1 = ArrayUtils.get(values, 0);
+        Object val2 = ArrayUtils.get(values, 1);
+        return betweenIfPresent(column, val1, val2);
+    }
+
+    // ========== 重写父类方法，方便链式调用 ==========
+
+    @Override
+    public LambdaQueryWrapperX<T> eq(boolean condition, SFunction<T, ?> column, Object val) {
+        super.eq(condition, column, val);
+        return this;
+    }
+
+    @Override
+    public LambdaQueryWrapperX<T> eq(SFunction<T, ?> column, Object val) {
+        super.eq(column, val);
+        return this;
+    }
+
+    @Override
+    public LambdaQueryWrapperX<T> orderByDesc(SFunction<T, ?> column) {
+        super.orderByDesc(true, column);
+        return this;
+    }
+
+    @Override
+    public LambdaQueryWrapperX<T> last(String lastSql) {
+        super.last(lastSql);
+        return this;
+    }
+
+    @Override
+    public LambdaQueryWrapperX<T> in(SFunction<T, ?> column, Collection<?> coll) {
+        super.in(column, coll);
+        return this;
+    }
+
+}
diff --git a/src/main/java/com/guwan/backend/service/impl/UserServiceImpl.java b/src/main/java/com/guwan/backend/service/impl/UserServiceImpl.java
index cb015a7..ddb1a44 100644
--- a/src/main/java/com/guwan/backend/service/impl/UserServiceImpl.java
+++ b/src/main/java/com/guwan/backend/service/impl/UserServiceImpl.java
@@ -7,6 +7,7 @@ import com.guwan.backend.dto.user.RegisterDTO;
 import com.guwan.backend.dto.user.UserDTO;
 import com.guwan.backend.entity.User;
 import com.guwan.backend.mapper.UserMapper;
+import com.guwan.backend.mybatis.query.LambdaQueryWrapperX;
 import com.guwan.backend.service.EmailService;
 import com.guwan.backend.service.UserService;
 import com.guwan.backend.util.JwtUtil;
@@ -92,7 +93,7 @@ public class UserServiceImpl implements UserService {
         System.out.println("request = " + request);
 
         if (request.getActiveTab().equals("account")) {
-            user = userMapper.selectOne(new LambdaQueryWrapper<User>().eq(User::getUsername, request.getUsername()));
+            user = userMapper.selectOne(new LambdaQueryWrapperX<User>().eqIfPresent(User::getUsername, request.getUsername()));
             if (user == null || !passwordEncoder.matches(request.getPassword(), user.getPassword())) {
                 throw new IllegalArgumentException("用户名或密码错误");
             }