diff --git a/src/main/java/com/study/design/MockDb.java b/src/main/java/com/study/design/items/MockDb.java
similarity index 88%
rename from src/main/java/com/study/design/MockDb.java
rename to src/main/java/com/study/design/items/MockDb.java
index 3c87461d3315968446d4e788ed9fbde3e81b2ae0..237d6767777216dfeab04a2450d603f783a7e92e 100644
--- a/src/main/java/com/study/design/MockDb.java
+++ b/src/main/java/com/study/design/items/MockDb.java
@@ -1,10 +1,18 @@
-package com.study.design;
+package com.study.design.items;
 
 import com.study.design.items.node.ProductItem;
 
 import java.util.ArrayList;
 import java.util.List;
 
+
+/**
+ * 多级目录mock数据
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:46
+ */
 public class MockDb {
     public static ProductItem ProductItem = new ProductItem();
 
diff --git a/src/main/java/com/study/design/items/node/AbstractProductItem.java b/src/main/java/com/study/design/items/node/AbstractProductItem.java
index 1c53b1389f291da651b6bcd32fde77c8f2052a53..9c8a82dbf6f7759cf8f739b76842d6fd10d994bc 100644
--- a/src/main/java/com/study/design/items/node/AbstractProductItem.java
+++ b/src/main/java/com/study/design/items/node/AbstractProductItem.java
@@ -1,6 +1,25 @@
 package com.study.design.items.node;
 
+
+/**
+ * 抽象节点
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:48
+ */
 public abstract class AbstractProductItem {
+    /**
+     * 删除子节点
+     *
+     * @param item
+     */
     public abstract void removeChild(AbstractProductItem item);
+
+    /**
+     * 新增子节点
+     *
+     * @param item
+     */
     public abstract void addChild(AbstractProductItem item);
 }
diff --git a/src/main/java/com/study/design/items/node/ProductItem.java b/src/main/java/com/study/design/items/node/ProductItem.java
index d03d17f41fba881f689e6231c472f5cc1eb37a9d..d5a3e464c7eb6ad65626c6cdc6b6d6773cd1cb1d 100644
--- a/src/main/java/com/study/design/items/node/ProductItem.java
+++ b/src/main/java/com/study/design/items/node/ProductItem.java
@@ -4,16 +4,36 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
-public class ProductItem extends AbstractProductItem{
+
+/**
+ * 数据节点
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:47
+ */
+public class ProductItem extends AbstractProductItem {
+    /**
+     * id
+     */
     private int id;
+    /**
+     * 父id
+     */
     private int pid;
+    /**
+     * 名称
+     */
     private String name;
+    /**
+     * 子节点集合
+     */
     private List<ProductItem> child = new ArrayList<>();
 
     @Override
     public void removeChild(AbstractProductItem item) {
         ProductItem removeItem = (ProductItem) item;
-        this.child = child.stream().filter(x->x.getId() != removeItem.getId()).collect(Collectors.toList());
+        this.child = child.stream().filter(x -> x.getId() != removeItem.getId()).collect(Collectors.toList());
     }
 
     @Override
diff --git a/src/main/java/com/study/design/items/visitor/AddItemVisitor.java b/src/main/java/com/study/design/items/visitor/AddItemVisitor.java
index 658348252793b0ea4cdfe39086928fae27dd98bd..a2eea51031afbd5f1cb34d314e2acfe082d23dca 100644
--- a/src/main/java/com/study/design/items/visitor/AddItemVisitor.java
+++ b/src/main/java/com/study/design/items/visitor/AddItemVisitor.java
@@ -1,19 +1,27 @@
 package com.study.design.items.visitor;
 
-import com.study.design.MockDb;
+import com.study.design.items.MockDb;
 import com.study.design.items.node.ProductItem;
 import org.springframework.stereotype.Component;
 
+
+/**
+ * 添加节点访问者
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:46
+ */
 @Component
-public class AddItemVisitor implements ItemVisitor<ProductItem>{
-    // 入参是 id 2, pid为 1
+public class AddItemVisitor implements ItemVisitor<ProductItem> {
+
     @Override
     public ProductItem visitor(ProductItem productItem) {
         ProductItem currentItem = MockDb.ProductItem; //  从缓存来的 to do
-        if(productItem.getId() == currentItem.getId()) {
+        if (productItem.getId() == currentItem.getId()) {
             throw new UnsupportedOperationException("根节点是唯一的。");
         }
-        if(productItem.getPid() == currentItem.getId()) {
+        if (productItem.getPid() == currentItem.getId()) {
             currentItem.addChild(productItem);
             return currentItem;
         }
@@ -22,8 +30,8 @@ public class AddItemVisitor implements ItemVisitor<ProductItem>{
     }
 
     private void addChild(ProductItem productItem, ProductItem currentItem) {
-        for(ProductItem item : currentItem.getChild()) {
-            if(item.getId() == productItem.getPid()) {
+        for (ProductItem item : currentItem.getChild()) {
+            if (item.getId() == productItem.getPid()) {
                 item.addChild(productItem);
                 break;
             } else {
diff --git a/src/main/java/com/study/design/items/visitor/DelItemVisitor.java b/src/main/java/com/study/design/items/visitor/DelItemVisitor.java
index 08dbb6abf8546b3ac333102dde3278fe10fd1ebf..2d41ae20b472adf907143661ce5d0bcce570660d 100644
--- a/src/main/java/com/study/design/items/visitor/DelItemVisitor.java
+++ b/src/main/java/com/study/design/items/visitor/DelItemVisitor.java
@@ -1,19 +1,27 @@
 package com.study.design.items.visitor;
 
-import com.study.design.MockDb;
+import com.study.design.items.MockDb;
 import com.study.design.items.node.ProductItem;
 import org.springframework.stereotype.Component;
 
+
+/**
+ * 删除节点访问者
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:46
+ */
 @Component
-public class DelItemVisitor implements ItemVisitor<ProductItem>{
-    // 入参是 id 2, pid为 1
+public class DelItemVisitor implements ItemVisitor<ProductItem> {
+
     @Override
     public ProductItem visitor(ProductItem productItem) {
         ProductItem currentItem = MockDb.ProductItem; //  从缓存来的 to do
-        if(productItem.getId() == currentItem.getId()) {
+        if (productItem.getId() == currentItem.getId()) {
             throw new UnsupportedOperationException("根节点不能删。");
         }
-        if(productItem.getPid() == currentItem.getId()) {
+        if (productItem.getPid() == currentItem.getId()) {
             currentItem.removeChild(productItem);
             return currentItem;
         }
@@ -22,8 +30,8 @@ public class DelItemVisitor implements ItemVisitor<ProductItem>{
     }
 
     private void delChild(ProductItem productItem, ProductItem currentItem) {
-        for(ProductItem item : currentItem.getChild()) {
-            if(item.getId() == productItem.getPid()) {
+        for (ProductItem item : currentItem.getChild()) {
+            if (item.getId() == productItem.getPid()) {
                 item.removeChild(productItem);
                 break;
             } else {
diff --git a/src/main/java/com/study/design/items/visitor/ItemVisitor.java b/src/main/java/com/study/design/items/visitor/ItemVisitor.java
index ef12cbd8ce771c0ae12abfec9832a15fca4fb5f0..c6a6dc5011b423519071624e9afdff556f09c397 100644
--- a/src/main/java/com/study/design/items/visitor/ItemVisitor.java
+++ b/src/main/java/com/study/design/items/visitor/ItemVisitor.java
@@ -2,6 +2,20 @@ package com.study.design.items.visitor;
 
 import com.study.design.items.node.ProductItem;
 
+
+/**
+ * 访问者接口
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:46
+ */
 public interface ItemVisitor<T> {
+    /**
+     * 访问行为
+     *
+     * @param productItem
+     * @return
+     */
     T visitor(ProductItem productItem);
 }
diff --git a/src/main/java/com/study/design/service/ItemService.java b/src/main/java/com/study/design/service/ItemService.java
index cf36d020983e40e161f3f7f35d5faab0e5e66271..90b02856c49b9a068c4d63c193c92fe617fc3948 100644
--- a/src/main/java/com/study/design/service/ItemService.java
+++ b/src/main/java/com/study/design/service/ItemService.java
@@ -1,17 +1,24 @@
 package com.study.design.service;
 
-import com.study.design.MockDb;
+import com.study.design.items.MockDb;
 import com.study.design.items.node.ProductItem;
 import com.study.design.items.visitor.AddItemVisitor;
 import com.study.design.items.visitor.DelItemVisitor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
+/**
+ * 树结构节点service
+ *
+ * @author : qinyingjie
+ * @version : 2.2.0
+ * @date : 2023/7/30 19:49
+ */
 @Service
 public class ItemService {
+
     @Autowired
     private DelItemVisitor delItemVisitor;
-
     @Autowired
     private AddItemVisitor addItemVisitor;