diff --git a/src/main/resources/mapper/PostMapper.xml b/src/main/resources/mapper/PostMapper.xml
new file mode 100644
index 0000000..e676fcc
--- /dev/null
+++ b/src/main/resources/mapper/PostMapper.xml
@@ -0,0 +1,103 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
+        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+
+<mapper namespace="com.pt5.pthouduan.mapper.PostMapper">
+
+    <!-- 插入帖子 -->
+    <insert id="save" parameterType="com.pt5.pthouduan.entity.Post"
+            useGeneratedKeys="true" keyProperty="postid" keyColumn="postid">
+        INSERT INTO post (
+            userid,
+            photo,
+            rannge,
+            is_pinned,
+            post_title,
+            post_content,
+            postCreatedTime,
+            updated_time,
+            tags,
+            likes
+        ) VALUES (
+                     #{userid},
+                     #{photo},
+                     #{rannge},
+                     #{is_pinned},
+                     #{post_title},
+                     #{post_content},
+                     #{postCreatedTime},
+                     #{updated_time},
+                     #{tags},
+                     COALESCE(#{likes}, 0)
+                 )
+    </insert>
+
+    <!-- 删除帖子 -->
+    <delete id="deleteByPostid" parameterType="int">
+        DELETE FROM post WHERE postid = #{postid}
+    </delete>
+
+    <!-- 更新帖子 -->
+    <update id="updatePost" parameterType="com.pt5.pthouduan.entity.Post">
+        UPDATE post
+        SET
+            userid = #{userid},
+            photo = #{photo},
+            rannge = #{rannge},
+            updated_time = #{updated_time},
+            is_pinned = #{is_pinned},
+            post_title = #{post_title},
+            post_content = #{post_content},
+            postCreatedTime = #{postCreatedTime},
+            tags = #{tags},
+            likes = COALESCE(#{likes}, 0)
+        WHERE postid = #{postid}
+    </update>
+
+    <!-- 模糊搜索帖子 -->
+    <select id="searchByKeyword" resultType="com.pt5.pthouduan.entity.Post">
+        SELECT * FROM post
+        WHERE post_title LIKE CONCAT('%', #{keyword}, '%')
+           OR tags LIKE CONCAT('%', #{keyword}, '%')
+    </select>
+
+    <!-- 点赞 +1 -->
+    <update id="incrementLikes" parameterType="int">
+        UPDATE post
+        SET likes = likes + 1
+        WHERE postid = #{postid}
+    </update>
+
+    <!-- 取消点赞 -->
+    <update id="decrementLikes" parameterType="int">
+        UPDATE post
+        SET likes = CASE WHEN likes > 0 THEN likes - 1 ELSE 0 END
+        WHERE postid = #{postid}
+    </update>
+
+    <!-- 更新置顶状态 -->
+    <update id="updatePinnedStatus" parameterType="map">
+        UPDATE post
+        SET is_pinned = #{pinned}
+        WHERE postid = #{postid}
+    </update>
+
+    <!-- 根据用户 ID 查询其所有帖子 -->
+    <select id="findByUserid" resultType="com.pt5.pthouduan.entity.Post">
+        SELECT * FROM post
+        WHERE userid = #{userid}
+    </select>
+
+    <!-- 查询所有置顶帖子 -->
+    <select id="findPinnedPosts" resultType="com.pt5.pthouduan.entity.Post">
+        SELECT * FROM post
+        WHERE is_pinned = TRUE
+    </select>
+
+    <!-- 查询所有帖子，按置顶优先、创建时间倒序 -->
+    <select id="selectAllSorted" resultType="com.pt5.pthouduan.entity.Post">
+        SELECT * FROM post
+        ORDER BY is_pinned DESC, postCreatedTime DESC
+    </select>
+
+</mapper>