From e54a1aa0b8e6b1cfc83773b693eaa862dd9d4bc9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=AB=98=E9=93=81?= <szujobs@gmail.com>
Date: Tue, 3 Oct 2017 15:05:42 -0500
Subject: [PATCH] Updated Druid_SQL_AST (markdown)

---
 Druid_SQL_AST.md | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Druid_SQL_AST.md b/Druid_SQL_AST.md
index dc25c8d..0485e2b 100644
--- a/Druid_SQL_AST.md
+++ b/Druid_SQL_AST.md
@@ -179,5 +179,19 @@ String dbType = JdbcConstants.MYSQL;
 SQLExpr expr = SQLUtils.toSQLExpr("id=3", dbType);
 ```
 
-## 4. 如何遍历AST节点
+# 4. 怎样打印AST节点
+## 4.1通过SQLUtils工具类打印节点
+```java
+package com.alibaba.druid.sql;
+
+public class SQLUtils {
+    // 可以将SQLExpr/SQLStatement打印为String类型
+    static String toSQLString(SQLObject sqlObj, String dbType);
+
+    // 可以将一个&lt;SQLStatement&gt;打印为String类型
+    static String toSQLString(List<SQLStatement> statementList, String dbType);
+}
+```
+
+# 5. 如何自定义遍历AST节点
 所有的AST节点都支持Visitor模式，需要自定义遍历逻辑，可以实现相应的ASTVisitorAdapter派生类，比如 https://github.com/alibaba/druid/wiki/SQL_Parser_Demo_visitor
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