diff --git a/src/main/resources/mapper/CommentMapper.xml b/src/main/resources/mapper/CommentMapper.xml
new file mode 100644
index 0000000..81e4581
--- /dev/null
+++ b/src/main/resources/mapper/CommentMapper.xml
@@ -0,0 +1,54 @@
+<?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.CommentMapper">
+
+    <!-- 创建评论 -->
+    <insert id="save" parameterType="com.pt5.pthouduan.entity.Comment">
+        INSERT INTO comment (commentid, userid, postid, post_commentcontent, commenttime)
+        VALUES (#{commentid}, #{userid}, #{postid}, #{postCommentcontent}, #{commenttime})
+    </insert>
+
+    <!-- 删除评论 -->
+    <delete id="deleteByCommentid" parameterType="int">
+        DELETE FROM comment WHERE commentid = #{commentid}
+    </delete>
+
+    <!-- 更新评论 -->
+    <update id="updateComment" parameterType="com.pt5.pthouduan.entity.Comment">
+        UPDATE comment
+        SET userid = #{userid},
+            postid = #{postid},
+            post_commentcontent = #{postCommentcontent},
+            commenttime = #{commenttime}
+        WHERE commentid = #{commentid}
+    </update>
+
+    <!-- 按帖子ID查询所有评论 -->
+    <select id="selectByPostid" parameterType="int" resultType="com.pt5.pthouduan.entity.Comment">
+        SELECT * FROM comment
+        WHERE postid = #{postid}
+        ORDER BY commenttime ASC
+    </select>
+
+    <!-- 点赞 +1 -->
+    <update id="incrementLikes" parameterType="int">
+        UPDATE comment
+        SET likes = likes + 1
+        WHERE commentid = #{commentid}
+    </update>
+
+    <!-- 取消点赞 -1（最小为0） -->
+    <update id="decrementLikes" parameterType="int">
+        UPDATE comment
+        SET likes = CASE
+                        WHEN likes > 0 THEN likes - 1
+                        ELSE 0
+            END
+        WHERE commentid = #{commentid}
+    </update>
+
+
+</mapper>