diff --git a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/AbstractBotCode.java b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/AbstractBotCode.java
index 4d34adb..0548f69 100644
--- a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/AbstractBotCode.java
+++ b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/AbstractBotCode.java
@@ -116,19 +116,4 @@ public abstract class AbstractBotCode implements BotCode {
         return Collections.unmodifiableSet(functionProperties.keySet());
     }
 
-    @Override
-    public int length() {
-        return contentToString().length();
-    }
-
-    @Override
-    public char charAt(int index) {
-        return contentToString().charAt(index);
-    }
-
-    @Override
-    public CharSequence subSequence(int start, int end) {
-        return contentToString().subSequence(start, end);
-    }
-
 }
diff --git a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/CharSequenceMessage.java b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/CharSequenceMessage.java
index 9114fd6..8c770b7 100644
--- a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/CharSequenceMessage.java
+++ b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/CharSequenceMessage.java
@@ -39,21 +39,6 @@ public final class CharSequenceMessage implements Message {
         return content.toString();
     }
 
-    @Override
-    public int length() {
-        return content.length();
-    }
-
-    @Override
-    public char charAt(int index) {
-        return content.charAt(index);
-    }
-
-    @Override
-    public CharSequence subSequence(int start, int end) {
-        return content.subSequence(start, end);
-    }
-
     @Override
     public String toString() {
         return "CharSequenceMessage{" +
diff --git a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/Message.java b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/Message.java
index 9493cb9..23737fc 100644
--- a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/Message.java
+++ b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/Message.java
@@ -29,4 +29,39 @@ public interface Message extends CharSequence {
      */
     String contentToString();
 
+    /**
+     * 返回该消息经过 {@link #contentToString()} 后的字符串长度.
+     * @return 返回 {@link #contentToString()} 返回字符串的长度.
+     * @see CharSequence#length()
+     */
+    @Override
+    default int length() {
+        return contentToString().length();
+    }
+
+    /**
+     * 从 {@link #contentToString()} 所返回的字符串中取出指定索引的字符.
+     * @param index 字符索引.
+     * @return 返回字符串指定索引对应的字符.
+     * @throws IndexOutOfBoundsException 如果索引参数为负数或不小于此字符串的长度.
+     * @see CharSequence#charAt(int)
+     */
+    @Override
+    default char charAt(int index) {
+        return contentToString().charAt(index);
+    }
+
+    /**
+     * 截取从 {@link #contentToString()} 中返回字符串内的一段字符序列.
+     * @param start 截取起始索引.
+     * @param end 截取终止索引.
+     * @return 返回新的字符序列对象.
+     * @throws IndexOutOfBoundsException 如果 beginIndex 或 endIndex 为负,
+     *                                   endIndex 大于 {@link #length()}, 或者 beginIndex 大于 endIndex 时抛出.
+     * @see CharSequence#subSequence(int, int)
+     */
+    @Override
+    default CharSequence subSequence(int start, int end) {
+        return contentToString().subSequence(start, end);
+    }
 }
diff --git a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/MessageChain.java b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/MessageChain.java
index fdbc076..c46f580 100644
--- a/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/MessageChain.java
+++ b/ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/MessageChain.java
@@ -85,19 +85,4 @@ public final class MessageChain implements Message {
         return builder.toString();
     }
 
-    @Override
-    public int length() {
-        return contentToString().length();
-    }
-
-    @Override
-    public char charAt(int index) {
-        return contentToString().charAt(index);
-    }
-
-    @Override
-    public CharSequence subSequence(int start, int end) {
-        return contentToString().subSequence(start, end);
-    }
-
 }