diff --git a/pattern-command/src/main/java/org/panda/App.java b/pattern-command/src/main/java/org/panda/App.java
deleted file mode 100644
index 5e4b9bf..0000000
--- a/pattern-command/src/main/java/org/panda/App.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package org.panda;
-
-/**
- * Hello world!
- *
- */
-public class App 
-{
-    public static void main( String[] args )
-    {
-        System.out.println( "Hello World!" );
-    }
-}
diff --git a/pattern-command/src/main/java/org/panda/command/DrawCanvas.java b/pattern-command/src/main/java/org/panda/command/DrawCanvas.java
index fe0871f..bd42c02 100644
--- a/pattern-command/src/main/java/org/panda/command/DrawCanvas.java
+++ b/pattern-command/src/main/java/org/panda/command/DrawCanvas.java
@@ -2,21 +2,34 @@ package org.panda.command;
 
 import java.awt.*;
 
+/**
+ * 绘制类
+ * @author qi
+ */
 public class DrawCanvas extends Canvas implements Drawable {
 
-    //颜色
+    /**
+     * 颜色
+     */
     private Color color = Color.red;
-    //要绘制的圆点半径
+    /**
+     * 要绘制的圆点半径
+     */
     private int radius = 6;
-    //命令的历史记录
+    /**
+     *命令的历史记录
+     */
     private MacroCommand history;
-    //构造函数
+    /**
+     * 构造函数
+     */
     public DrawCanvas(int width,int height,MacroCommand history) {
         setSize(width,height);
         setBackground(Color.white);
         this.history = history;
     }
 
+    @Override
     public void paint(Graphics graphics){
         history.execute();
     }