refactor && enhance mysql sql parser support

src/test/java/com/alibaba/druid/bvt/sql/cobar/LiteralHexadecimalTest.java

@@ -0,0 +1,51 @@
+/**
+ * (created at 2011-11-11)
+ */
+package com.alibaba.druid.bvt.sql.cobar;
+
+import junit.framework.Assert;
+import junit.framework.TestCase;
+
+import com.alibaba.druid.sql.ast.expr.SQLHexExpr;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlExprParser;
+
+/**
+ * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
+ */
+public class LiteralHexadecimalTest extends TestCase {
+    public void test_0() throws Exception {
+        String sql = "x'E982B1E7A195275C73'";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("邱硕'\\s", new String(hex.toBytes(), "utf-8"));
+    }
+
+    public void test_1() throws Exception {
+        String sql = "x'0D0A'";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("\r\n", new String(hex.toBytes(), "utf-8"));
+    }
+    
+    public void test_2() throws Exception {
+        String sql = "X'4D7953514C'";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("MySQL", new String(hex.toBytes(), "utf-8"));
+    }
+    
+    public void test_3() throws Exception {
+        String sql = "0x5061756c";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("Paul", new String(hex.toBytes(), "utf-8"));
+    }
+    
+    public void test_4() throws Exception {
+        String sql = "0x41";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("A", new String(hex.toBytes(), "utf-8"));
+    }
+    
+    public void test_5() throws Exception {
+        String sql = "0x636174";
+        SQLHexExpr hex = (SQLHexExpr) new MySqlExprParser(sql).expr();
+        Assert.assertEquals("cat", new String(hex.toBytes(), "utf-8"));
+    }
+}